The DOI matches its Crossref record; 41 of the 41 references it cites were found in a registry or an index; 18 of the 46 sources its claims cite were checked for support.
Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness.
Open accessAbstract
In the past 50 y, there has been a decline in average sleep duration and quality, with adverse consequences on general health. A representative survey of 1,508 American adults recently revealed that 90% of Americans used some type of electronics at least a few nights per week within 1 h before bedtime. Mounting evidence from countries around the world shows the negative impact of such technology use on sleep. This negative impact on sleep may be due to the short-wavelength-enriched light emitted by these electronic devices, given that artificial-light exposure has been shown experimentally to produce alerting effects, suppress melatonin, and phase-shift the biological clock. A few reports have shown that these devices suppress melatonin levels, but little is known about the effects on circadian phase or the following sleep episode, exposing a substantial gap in our knowledge of how this increasingly popular technology affects sleep. Here we compare the biological effects of reading an electronic book on a light-emitting device (LE-eBook) with reading a printed book in the hours before bedtime. Participants reading an LE-eBook took longer to fall asleep and had reduced evening sleepiness, reduced melatonin secretion, later timing of their circadian clock, and reduced next-morning alertness than when reading a printed book. These results demonstrate that evening exposure to an LE-eBook phase-delays the circadian clock, acutely suppresses melatonin, and has important implications for understanding the impact of such technologies on sleep, performance, health, and safety.
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Claims the paper makes
14 Own method · 13 Own result · 10 Own interpretation · 6 Partly supported · 5 Supported · 5 No full text of the sources · 2 Not checked yet · 1 Supported so far · 1 No basis given · accuracy not yet measured
Every source the paper cites for this claim was checked and supports it.
In the paper
“The spectral composition of the light emitted by the LE-eBook may explain why the magnitude of the melatonin-suppressing and phase-shifting response observed was greater than would be predicted for this moderately low level of light (3).”
What the sources say
- Supportedcites [3] Zeitzer JM, Dijk DJ, Kronauer R, Brown E, Czeisler C (2000) Sensitivity of the human circadian pacemaker to nocturnal light: Melatonin phase resetting and suppression. J Physiol 526(Pt 3):695 -702. source
The Results (page unavailable) provide illuminance-based dose-response models for both melatonin suppression and phase shifting, supporting the cited paper's use as a benchmark for an expected response at a low light level. The proposed explanation involving the LE-eBook’s spectral composition is the citing authors’ interpretation, not a finding attributed to this source. (LLM, conf=0.83)
hedgedconditional- Asserted: passes — The authors put it forward as true.
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- Based: passes — The paper gives a reason why it holds.
- Supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“the 4-h exposure interval used in this study is likely in the range of screen time exposure experienced by millions of Americans each evening.”
What the sources say
- Partly supportedcites [36] Gradisar M, et al. (2013) The sleep and technology use of Americans: Findings from the National Sleep Foundation ' s 2011 Sleep in America poll. J Clin Sleep Med 9(12): 1291 -1299. sourceExperimental — accuracy not yet measured
Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.
hedged- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Partly supported
Every source the paper cites for this claim was checked and supports it.
In the paper
“Induction of such misalignment of circadian phase is likely to lead to chronic sleep deficiency (1).”
What the sources say
- Supportedcites [1] Czeisler CA (2013) Perspective: Casting light on sleep deficiency. Nature 497(7450): S13. source
The Abstract explains that evening light shifts the circadian clock later, delaying bedtime while people continue to rise early, thereby squeezing sleep. It also links increasing light consumption with rising sleep deficiency. This supports the claim that induced circadian misalignment is likely to cause ongoing sleep deficiency. (LLM, conf=0.87)
hedgedconditional- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“In humans, exposure to short-wavelength monochromatic light in the evening has been shown to induce greater circadian and alerting responses than exposure to the same number of photons of longer-wavelength monochromatic light (17 -19, 28 -34), even though the shorter-wavelength light may have a much lower illuminance level when measured in photopic lux (35).”
What the sources say
- Partly supportedcites [17] Chellappa SL, et al. (2011) Non-visual effects of light on melatonin, alertness and cognitive performance: Can blue-enriched light keep us alert? PLoS ONE 6(1):e16429. sourceExperimental — accuracy not yet measured
The Introduction and Discussion report stronger circadian and alerting effects from shorter-wavelength light in humans. But the Methods (Lighting settings; no page given) describe a comparison of polychromatic lamps at approximately equal photopic illuminance, not monochromatic lights with equal photon counts and lower photopic lux for the shorter wavelength. The paper therefore supports the wavelength-dependent response, but not the specific comparison or illuminance claim attributed to it. (LLM, conf=0.86)
- Not checked — no full text of the sourcecites [18] Cajochen C, et al. (2011) Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance. J Appl Physiol (1985) 110(5):1432 -1438. source
- Not checked — no full text of the sourcecites [19] Cajochen C, et al. (2005) High sensitivity of human melatonin, alertness, thermoregulation, and heart rate to short wavelength light. J Clin Endocrinol Metab 90(3): 1311 -1316. source
- Not checked — no full text of the sourcecites [28] Wood B, Rea MS, Plitnick B, Figueiro MG (2013) Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression. Appl Ergon 44(2):237 -240. source
- Supportedcites [29] Brainard GC, et al. (2001) Action spectrum for melatonin regulation in humans: Evidence for a novel circadian photoreceptor. J Neurosci 21(16):6405 -6412. sourceExperimental — accuracy not yet measured
Citation (35) is attached to the photopic-lux qualification, not the earlier claim about alerting responses. The Discussion (page unavailable) explains that photopic vision is most sensitive near 555 nm, while 460 nm light suppresses melatonin more strongly than 555 nm light at equal photon density. This supports the point that a short-wavelength stimulus can have a stronger circadian-related effect despite a lower photopic illuminance reading. (LLM, conf=0.86)
- Partly supportedcites [30] Thapan K, Arendt J, Skene DJ (2001) An action spectrum for melatonin suppression: Evidence for a novel non-rod, non-cone photoreceptor system in humans. J Physiol 535(Pt 1):261 -267. sourceExperimental — accuracy not yet measured
Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.
- Not checked — no full text of the sourcecites [31] Lockley SW, Brainard GC, Czeisler CA (2003) High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light. J Clin Endocrinol Metab 88(9):4502 -4505. source
- Not checked — no full text of the sourcecites [32] Lockley SW, et al. (2006) Short-wavelength sensitivity for the direct effects of light on alertness, vigilance, and the waking electroencephalogram in humans. Sleep 29(2): 161 -168. source
- Not checked — no full text of the sourcecites [33] Münch M, et al. (2006) Wavelength-dependent effects of evening light exposure on sleep architecture and sleep EEG power density in men. Am J Physiol Regul Integr Comp Physiol 290(5):R1421 -R1428. source
- Not checked — no full text of the sourcecites [34] Santhi N, et al. (2012) The spectral composition of evening light and individual differences in the suppression of melatonin and delay of sleep in humans. J Pineal Res 53(1):47 -59. source
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Suppression of melatonin by exposure to evening light may be an underlying mechanism by which light acutely increases alertness, as seen in the present study and in previous reports (14 -19).”
What the sources say
- Not checked — no full text of the sourcecites [14] Perrin F, et al. (2004) Nonvisual responses to light exposure in the human brain during the circadian night. Curr Biol 14(20):1842 -1846. source
- Supportedcites [15] Figueiro MG, Bullough JD, Bierman A, Fay CR, Rea MS (2007) On light as an alerting stimulus at night. Acta Neurobiol Exp (Wars) 67(2):171 -178. source
The Introduction explicitly proposes that suppression of melatonin by light may play a role in increasing alertness at night. The Results (p. 175) report that measured alertness closely tracked predictions of melatonin suppression, while the Conclusion cautions that this does not prove causality. The claim’s “may” preserves that uncertainty. (LLM, conf=0.90)
- Partly supportedcites [16] Revell VL, Barrett DC, Schlangen LJ, Skene DJ (2010) Predicting human nocturnal nonvisual responses to monochromatic and polychromatic light with a melanopsin photosensitivity function. Chronobiol Int 27(9 -10):1762 -1777. sourceExperimental — accuracy not yet measured
The Abstract (p. 4) reports that subjective alertness increased during nocturnal light exposure and that the study measured melatonin suppression. It does not establish that melatonin suppression mediates the alerting effect; the Abstract (p. 4) and Discussion (p. 16) instead note differences between the two responses across light conditions. (LLM, conf=0.87)
- Supportedcites [17] Chellappa SL, et al. (2011) Non-visual effects of light on melatonin, alertness and cognitive performance: Can blue-enriched light keep us alert? PLoS ONE 6(1):e16429. source
The Results (Melatonin suppression; page unavailable) explicitly examine whether lower melatonin levels could underlie improved performance and report significant correlations under 6500K light. The Discussion (page unavailable) says evening light stimulated alertness and performance in correlation with concomitant melatonin suppression. These passages support the proposed mechanism as a possibility, not a demonstrated cause. (LLM, conf=0.88)
- Not checked — no full text of the sourcecites [18] Cajochen C, et al. (2011) Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance. J Appl Physiol (1985) 110(5):1432 -1438. source
- Not checked — no full text of the sourcecites [19] Cajochen C, et al. (2005) High sensitivity of human melatonin, alertness, thermoregulation, and heart rate to short wavelength light. J Clin Endocrinol Metab 90(3): 1311 -1316. source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The following morning, however, the results for self-reported sleepiness were reversed, with participants feeling sleepier the morning after reading an LE-eBook the prior evening ( P < 0.001; Fig. 3 D ).”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Participants also had significantly less rapid eye movement (REM) sleep following the LE-eBook condition (109.04 ± 26.25 min vs. 120.86 ± 25.32 min in the print-book condition; P = 0.03; Fig. 3 B and C ), reflecting a lower average rate of accumulation of REM sleep during sleep (Fig. 3 B ).”
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In the LE-eBook condition, participants averaged nearly 10 min longer to fall asleep than in the print-book condition (mean ± SD, 25.65 ± 18.78 min vs. 15.75 ± 13.09 min; P = 0.009; mixed model; Fig. 3 A ).”
plain- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Furthermore, not only did they awaken feeling sleepier, it took them hours longer to fully ' wake up ' and attain the same level of alertness than in the printed book condition.”
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Dim light melatonin onset was > 1.5 h later on the day following the LE-eBook condition (22:31 ± 0:42) than in the print-book condition (21:01 ± 0:49; P < 0.001; Fig. 2 C and D ).”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- It may state two separate claims as one. 21
- Probably not a substantial claim. 18
- The quote only partly states this claim. 3
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“In humans, exposure to light in the evening and early part of the night, even at low intensity, suppresses the release of the sleep-facilitating hormone melatonin (3 -5) and shifts the circadian clock to a later time (3, 6), both of which make it more difficult to fall asleep at night.”
What the sources say
- Supportedcites [3] Zeitzer JM, Dijk DJ, Kronauer R, Brown E, Czeisler C (2000) Sensitivity of the human circadian pacemaker to nocturnal light: Melatonin phase resetting and suppression. J Physiol 526(Pt 3):695 -702. source
The Abstract reports that early-biological-night light delayed the human circadian pacemaker and acutely suppressed plasma melatonin. It also reports substantial effects at approximately 100 lux. The statement about difficulty falling asleep is the citing authors’ inference, rather than a finding directly attributed to this source. (LLM, conf=0.92)
- Not checked — no full text of the sourcecites [4] McIntyre IM, Norman TR, Burrows GD, Armstrong SM (1989) Human melatonin suppression by light is intensity dependent. J Pineal Res 6(2):149 -156. source
- Not checked — no full text of the sourcecites [5] Brainard GC, et al. (1988) Dose-response relationship between light irradiance and the suppression of plasma melatonin in human volunteers. Brain Res 454(1-2):212 -218. source
- Partly supportedcites [6] Khalsa SBS, Jewett ME, Cajochen C, Czeisler CA (2003) A phase response curve to single bright light pulses in human subjects. J Physiol 549(Pt 3):945 -952. sourceExperimental — accuracy not yet measured
The Abstract and Results (pages not provided) report that bright-light exposure caused phase delays when timed before the core body temperature minimum; the Discussion also suggests small phase-shifting effects of dim light. The paper does not establish that low-intensity evening light suppresses melatonin release or makes it harder to fall asleep. (LLM, conf=0.88)
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Supported
Every source the paper cites for this claim was checked and supports it.
In the paper
“For this reason, it has recently been proposed that lux is an inappropriate measure for estimation of the impact of light on melatonin suppression, circadian-phase shifting, and other non -imageforming effects of retinal light exposure (35).”
What the sources say
- Supportedcites [35] Lucas RJ, et al. (2014) Measuring and using light in the melanopsin age. Trends Neurosci 37(1):1 -9. source
In “Light as a regulator of physiology and behavior” (page not supplied), the paper says photopic lux is inadequate for quantifying light intended to regulate non-visual physiology and behavior. The same section identifies circadian phase resetting and melatonin suppression as non-visual responses. (LLM, conf=0.94)
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Supported
Every source the paper cites for this claim was checked and supports it.
In the paper
“The use of light-emitting devices immediately before bedtime is a concern because light is the most potent environmental signal that impacts the human circadian clock and may therefore play a role in perpetuating sleep deficiency (1).”
What the sources say
- Supportedcites [1] Czeisler CA (2013) Perspective: Casting light on sleep deficiency. Nature 497(7450): S13. source
The paper says that light powerfully affects circadian rhythms and that exposure after sunset shifts the circadian clock later, delaying sleep (Abstract, passages 3–4). It also identifies screens and handheld devices as sources of LED light and says night-time exposure can disrupt circadian rhythms and sleep (Abstract, passage 1). (LLM, conf=0.90)
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Supported
Every source the paper cites for this claim was checked and supports it.
In the paper
“The circadian-timing system synchronizes numerous internal physiological and biochemical processes, including the daily rhythm of sleep propensity (2), to external environmental time cues.”
What the sources say
- Supportedcites [2] Dijk DJ, Czeisler CA (1995) Contribution of the circadian pacemaker and the sleep homeostat to sleep propensity, sleep structure, electroencephalographic slow waves, and sleep spindle activity in humans. J Neurosci 15(5 Pt 1):3526 -3538. source
The introduction describes light as the principal synchronizer of the human circadian pacemaker and identifies its role in regulating physiological rhythms and sleep timing. The Additional information section explicitly describes an endogenous circadian rhythm of sleep propensity under entrained conditions. (LLM, conf=0.90)
plaindirect- Asserted: passes — The authors put it forward as true.
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Probably not a substantial claim.
- Supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“The results of this study are of particular concern, given recent evidence linking chronic suppression of melatonin secretion by nocturnal light exposure with the increased risk of breast, colorectal, and advanced prostate cancer associated with night-shift work (for review, see ref. 10), which has now been classified as a probable carcinogen by the World Health Organization (11, 12).”
What the sources say
- Partly supportedcites [10] Costa G, Haus E, Stevens R (2010) Shift work and cancer - considerations on rationale, mechanisms, and epidemiology. Scand J Work Environ Health 36(2):163 -179. sourceExperimental — accuracy not yet measured
The “Shift work and cancer” section reports moderately increased breast-cancer risk after prolonged shift work, more limited observations for colorectal and prostate cancers, and IARC’s classification of shift work involving circadian disruption as probably carcinogenic (page unavailable). “Concluding remarks” links light-at-night melatonin suppression to breast cancer and possibly prostate cancer, but the copy does not establish that mechanism for colorectal cancer or specify advanced prostate cancer. The WHO-classification clause has separate citations in the citing sentence. (LLM, conf=0.86)
- Not checked — no full text of the sourcecites [11] Straif K, et al. (2007) Carcinogenicity of shift-work, painting, and fire-fighting. Lancet Oncol 8(12):1065 -1066. source
- Partly supportedcites [12] Erren TC (2010) Shift work, cancer and ' white-box ' epidemiology: Association and causation. Epidemiol Perspect Innov 7:11. sourceExperimental — accuracy not yet measured
The Discussion (pages not provided) describes nocturnal light as suppressing melatonin and reports increased breast-cancer risk in shift workers and findings compatible with increased prostate-cancer risk. It does not report a colorectal-cancer association or distinguish advanced prostate cancer, and it cautions that the observed risks may not reflect a real association with chronodisruption. The probable-carcinogen classification is attributed to other references in the citing sentence. (LLM, conf=0.86)
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
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- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Partly supported
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“The KSS is a 9-point Likert scale with all numbers having valid point values, but only the odd numbers have descriptions: 1 representing ' extremely alert, ' 3 representing ' alert, ' 5 representing ' neither alert nor sleepy, ' and 9 representing ' extremely sleepy ' (9, 41).”
What the sources say
- Not checked — no full text of the sourcecites [9] Åkerstedt T, Gillberg M (1990) Subjective and objective sleepiness in the active individual. Int J Neurosci 52(1 -2):29 -37. source
- Partly supportedcites [41] Gillberg M, Kecklund G, Åkerstedt T (1994) Relations between performance and subjective ratings of sleepiness during a night awake. Sleep 17(3):236 -241. sourceExperimental — accuracy not yet measured
The Methods (p. 2) describe the KSS as a nine-point scale from 1 (“very alert”) to 9 (“very sleepy, fighting sleep, an effort to keep awake”), with verbal descriptions at every second point. Our copy does not give the descriptions for points 3 and 5, so those specific labels in the citing sentence are not verified. (LLM, conf=0.84)
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“Other studies, however, have not found a relationship between alertness and melatonin levels during light exposure (20, 21) or have shown changes in alertness induced by light exposure during the day, when melatonin levels are at low or undetectable levels (22 -24).”
What the sources say
- Not checked — no full text of the sourcecites [20] Dollins AB, Lynch HJ, Wurtman RJ, Deng MH, Lieberman HR (1993) Effects of illumination on human nocturnal serum melatonin levels and performance. Physiol Behav 53(1):153 -160. source
- Not checked — no full text of the sourcecites [21] Chang AM, Scheer FA, Czeisler CA, Aeschbach D (2013) Direct effects of light on alertness, vigilance, and the waking electroencephalogram in humans depend on prior light history. Sleep 36(8):1239 -1246. source
- Not checked — no full text of the sourcecites [22] Phipps-Nelson J, Redman JR, Dijk DJ, Rajaratnam SM (2003) Daytime exposure to bright light, as compared to dim light, decreases sleepiness and improves psychomotor vigilance performance. Sleep 26(6):695 -700. source
- Supportedcites [23] Rüger M, Gordijn MC, Beersma DG, de Vries B, Daan S (2006) Time-of-day-dependent effects of bright light exposure on human psychophysiology: Comparison of daytime and nighttime exposure. AmJPhysiol Regul Integr Comp Physiol 290(5):R1413 -R1420. source
The Discussion (p. 7) reports that bright light reduced daytime sleepiness and had alerting effects even though almost no melatonin is secreted during the day. This supports the daytime-light portion of the citing sentence for which this paper is offered. (LLM, conf=0.93)
- Not checked — no full text of the sourcecites [24] Vandewalle G, et al. (2006) Daytime light exposure dynamically enhances brain responses. Curr Biol 16(16):1616 -1621. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The LE-e-book condition suppressed evening levels of melatonin by 55.12 ± 20.12%, whereas the print-book condition showed no suppression ( -18.77 ± 39.57%) as measured during the fifth night ( P < 0.001; Fig. 2 A and B ).”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Reading the LE-eBook was associated with decreased sleepiness in the evening. An hour before bedtime, study participants rated themselves as less sleepy ( P < 0.01; Fig. 3 D ), and their EEG showed less power within the delta/theta frequency range (1.0 -7.5 Hz; Fig. 3 D and E ) in the LE-eBook condition.”
plaincorrelational- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“As shown in Table S1, measurements from several other lightemitting devices are also enriched for short-wavelength light.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“There was no difference between conditions in TST, sleep efficiency, or the duration of non-REM sleep (stages 1 -3; Fig. 3 C ) in the sleep episode, which were scheduled for eight hours each.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Light from the LE-eBook is short-wavelength -enriched, with a peak at 452 nm in the blue light range, compared with broad-spectrum light (white light), with a peak at 612 nm.”
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Twelve young healthy adults completed the 14-d in-patient study protocol (six females and six males; mean age ± SD: 24.92 ± 2.87).”
plainn = 12- Asserted: passes — The authors put it forward as true.
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- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The peak irradiance for the LE-eBook eReader is ∼ 450 nm and for the reflected light is 612 nm.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“LE-eBook | 31.73 | 31.64 | 31.03 | 31.68 | 31.84 | 30.69”
- Also stated in: § Materials and Methods · p. 5 · plain
“Print book* | 0.91 | 0.45 | 0.65 | 0.68 | 0.81 | 0.92”
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
The quote only partly states this claim.
- Also stated in: § Materials and Methods · p. 5 · plain
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The decreased sleepiness before bedtime and longer sleep latency we observed in the LE-eBook condition is likely due to both an acute alerting effect of light and a delay of the circadian timing system.”
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Lastly, although the short-wavelength light from the LEeBook may have been responsible for the effects reported here, this study did not include a light-emitting device with longer wavelength for comparison, so our findings may be due to the difference in irradiance level rather than spectral composition.”
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The change in the timing of REM sleep likely represents a delay in the circadian rhythm of REM sleep propensity, which is temporally coincident with the sleep propensity rhythm (25).”
What the sources say
- Not checked — no full text of the sourcecites [25] Czeisler CA, Zimmerman JC, Ronda JM, Moore-Ede MC, Weitzman ED (1980) Timing of REM sleep is coupled to the circadian rhythm of body temperature in man. Sleep 2(3):329 -346. source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Therefore, the difference in morning sleepiness between the conditions is most likely due to differences in the prior sleep episode and/or the circadian-phase delay.”
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“All participants completed both reading conditions but were randomized to the order.”
plainn = 12- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Therefore, the greater suppression seen was not due to an effect of a delayed phase in the LE-eBook condition.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one. The quote only partly states this claim.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Moreover, in this study, the LE-eBook reader was held at a fixed distance (30 -45 cm) from the eye, further from the eye than many people might have chosen (therefore reducing retinal light exposure), particularly for users of smaller devices who may hold the smaller screens closer to the eyes.”
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Participants were instructed to refrain from use of medications, drugs, alcohol, nicotine, or caffeinated products for 3 wk before admission, which was verified by toxicological testing upon admission to the laboratory.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
In the paper
“The KDT allowed for waking EEG recording under standardized and reproducible conditions where artifacts from movement were minimized.”
What the sources say
- Not checked — no full text of the sourcecites [9] Åkerstedt T, Gillberg M (1990) Subjective and objective sleepiness in the active individual. Int J Neurosci 52(1 -2):29 -37. source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“We compared sleep and circadian measures between reading conditions using a mixed model analysis with factors Condition (LE-eBook or printed book), Order , and their Interaction ( Condition X Order ).”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Participants were randomized to the order of reading condition.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Mixed model was also used for comparing KSS score and EEG power with factors Condition , Order , Time (repeated measures in the first hour after awakening), and the Interaction ( Condition X Time ).”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“A technician was present for all reading sessions to coordinate and administer the reading session, ensure compliance of the participants, and collect and record the light measurements.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Participants were also required to maintain a fixed 8-h sleep schedule (10:00 PM to 6:00 AM), to complete a daily sleep/wake log, and to call in their bedtimes and wake times every day during this 3-wk interval. This sleep schedule was verified by wrist actigraphy (Actiwatch-L; Philips/Respironics) during the week before admission.”
plainn = 12- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The quote only partly states this claim.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Plasma melatonin samples were assayed (SolidPhase Inc., Portland, ME) using the BÜHLMANN Melatonin Radio-immunoassay (ALPCO Diagnostics, Salem, NH), which has a functional sensitivity of 0.9 pg/mL and an analytical sensitivity of 0.3 pg/mL, an intraassay precision of 7.9 -8.2%, and interassay precision of 11.7%.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Because of missing blood samples during the fifth night of one reading session, one study participant was excluded from analysis of melatonin suppression. Another participant was excluded from analysis of DLMO timing due to missing blood samples during one of the CPs. Therefore, melatonin suppression and phase were each determined in 11 participants.”
plainn = 11- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“The randomized, crossover protocol design consisted of two conditions: ( i ) reading an LE-eBook (iPad; Apple Inc., Cupertino, CA) in otherwise very dim room light for ∼ 4 h before bedtime for five consecutive evenings, and ( ii ) reading printed books in the same very dim room light for ∼ 4 h before bedtime for five consecutive evenings (Fig. 1).”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
The paper relies on this without support.
Little was known about the effects of light-emitting devices on circadian phase or the subsequent sleep episode.
“A few reports have shown that these devices suppress melatonin levels, but little is known about the effects on circadian phase or the following sleep episode, exposing a substantial gap in our knowledge of how this increasingly popular technology affects sleep.”
The paper relies on this without support.
For optimal sleep duration and quality, sleep timing must be aligned with the circadian clock.
“For optimal sleep duration and quality, the timing of the sleep episode must be appropriately aligned with the timing of the circadian clock.”
The paper relies on this without support.
Newer models of light-emitting devices are brighter than the one used in the study.
“However, a number of newer models of light-emitting devices are even brighter than those used in this study.”
The paper relies on this without support.
Many people hold light-emitting devices closer to the eyes than the 30-45 cm fixed distance used in the study.
“Moreover, in this study, the LE-eBook reader was held at a fixed distance (30 -45 cm) from the eye, further from the eye than many people might have chosen (therefore reducing retinal light exposure), particularly for users of smaller devices who may hold the smaller screens closer to the eyes.”
The paper relies on this without support.
Little was known about how evening light exposure affects alertness the following day.
“Light exposure in the biological evening/night also acutely increases alertness (7, 8), but not much is known about its impact on alertness the following day.”
The paper relies on this without support.
The effect size of eszopiclone on sleep latency in patients with primary insomnia is comparable to the effect of LE-eBook versus print book on sleep latency in young healthy adults.
“The 10-min-shorter sleep latency after the print-book condition compared with sleep latency after the LE-eBook condition is similar to the effect size of eszopiclone treatment on sleep latency in patients with primary insomnia (37).”
The paper relies on this without support.
The light exposure from the LE-eBook at maximum brightness in the study is representative of typical evening use of light-emitting electronic devices.
“This study demonstrates that use of a light-emitting electronic device in the hours before bedtime can have significant impact on sleep, alertness, and the circadian clock.”
“The LE-eBook was set to the maximum brightness setting.”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“We found that SOL partly mediated the associations between SNS use and depressive and anxiety symptoms, possibly explained by puberty-related circadian delay, psychological and physiological arousal from emotionally salient content before sleep, as well as melatonin suppression caused by screen light emission at bedtime [45–47].”
From Social networking site use, depressive and anxiety symptoms in adolescents: evidence from a longitudinal cohort study (SCAMP) (2026) · cites this paper as [47]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“Thus, short-wavelength light on the preceding evening reduced next-morning alertness because its alerting effects in the evening may have interfered with the subsequent sleep.”
From Preliminary Results: The Impact of Smartphone Use and Short-Wavelength Light during the Evening on Circadian Rhythm, Sleep and Alertness (2021) · cites this paper as [11]
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“In individuals reading e‐books before bed‐time, their circadian clock was delayed, assessed by delayed and reduced phase of rapid eye movement sleep. Melatonin blood concentration levels were suppressed and alertness on the next morning was reduced. Use of the light emitting e‐books immediately before bed time also increased alertness at that time.”
From The inner clock-Blue light sets the human rhythm (2019) · cites this paper as [73]
Experimental — accuracy not yet measuredThe cited source says what the claim attributes to it.
In the citing paper
“Light at night disturb sleep in humans (Esaki et al., 2019;Obayashi et al., 2014), possibly due to its inhibitory effect on melatonin secretion (Chang et al., 2015).”
From Sex-specific association of the lunar cycle with sleep (2022) · cites this paper as Chang et al., 2015
The cited source says what the claim attributes to it.
In the citing paper
“This finding is supported by other work that shows that not only is electronic media use near bedtime prevalent246 but also the light emitted by the devices247 as well as the mental engagement248 can interfere with sleep.”
From Sleep, Health, and Society (2017) · cites this paper as [247]
The cited source says what the claim attributes to it.
In the citing paper
“Second, lighting from the interaction with mobile phones or emailing late at night could disturb the biological circadian clock and increase alertness, both of which can influence sleep patterns [27,28].”
The cited source says what the claim attributes to it.
In the citing paper
“Chang and colleagues [26] for example found that reading a book from an e‑reader for four hours before sleep increased sleep onset latency, reduced evening sleepiness, melatonin secretion as well as next-morning alertness, and delayed the timing of the biological clock, which is also in line with other findings [72, 107].”
From Effects of light on human circadian rhythms, sleep and mood (2019) · cites this paper as [26]
The cited source says what the claim attributes to it.
In the citing paper
“Chang and colleagues [26] for example found that reading a book from an e‑reader for four hours before sleep increased sleep onset latency, reduced evening sleepiness, melatonin secretion as well as next-morning alertness, and delayed the timing of the biological clock, which is also in line with other findings [72, 107].”
From Effects of light on human circadian rhythms, sleep and mood (2019) · cites this paper as [26]
The cited source says what the claim attributes to it.
In the citing paper
“Chang and colleagues [26] for example found that reading a book from an e‑reader for four hours before sleep increased sleep onset latency, reduced evening sleepiness, melatonin secretion as well as next-morning alertness, and delayed the timing of the biological clock, which is also in line with other findings [72, 107].”
From Effects of light on human circadian rhythms, sleep and mood (2019) · cites this paper as [26]
The cited source says what the claim attributes to it.
In the citing paper
“Chang and colleagues [26] for example found that reading a book from an e‑reader for four hours before sleep increased sleep onset latency, reduced evening sleepiness, melatonin secretion as well as next-morning alertness, and delayed the timing of the biological clock, which is also in line with other findings [72, 107].”
From Effects of light on human circadian rhythms, sleep and mood (2019) · cites this paper as [26]
The cited source says what the claim attributes to it.
In the citing paper
“Chang and colleagues [26] for example found that reading a book from an e‑reader for four hours before sleep increased sleep onset latency, reduced evening sleepiness, melatonin secretion as well as next-morning alertness, and delayed the timing of the biological clock, which is also in line with other findings [72, 107].”
From Effects of light on human circadian rhythms, sleep and mood (2019) · cites this paper as [26]
The cited source says what the claim attributes to it.
In the citing paper
“Second, improper timing of exposure to the bright light of electronic devices can disrupt circadian rhythms, resulting in insomnia [24].”
From A serial mediation model of social media addiction and college students' academic engagement: the role of sleep quality and fatigue (2023) · cites this paper as [24]
The cited source says what the claim attributes to it.
In the citing paper
“Nevertheless, our findings for objective alertness 30 min after awakening are in line with these previous studies investigating subjective sleepiness.”
From Preliminary Results: The Impact of Smartphone Use and Short-Wavelength Light during the Evening on Circadian Rhythm, Sleep and Alertness (2021) · cites this paper as [11]
The cited source says what the claim attributes to it.
In the citing paper
“However, the finding that subjective sleepiness was higher during these first minutes after awakening when printed material was used for reading in the preceding evening was unexpected since previous research showed opposite results [9,11,42].”
From Preliminary Results: The Impact of Smartphone Use and Short-Wavelength Light during the Evening on Circadian Rhythm, Sleep and Alertness (2021) · cites this paper as [11]
The cited source says what the claim attributes to it.
In the citing paper
“Reading a light emitting e‐book before sleep, as compared with printed book, increased the time to fall asleep 73 in young adults (25 ± 3 years old).”
From The inner clock-Blue light sets the human rhythm (2019) · cites this paper as [73]
The cited source says what the claim attributes to it.
In the citing paper
“For example, the use of electronics during the night can unintentionally phase shift the circadian rhythm, leaving it decoupled from the natural environmental light–dark cycle45, with potentially dysregulated physiology and behavior.”
From Circadian rhythm disruption and mental health (2020) · cites this paper as [45]
In the citing paper
“plus screen light potentially delaying circadian rhythms and sleep [31]”
From Understanding Links Between Social Media Use, Sleep and Mental Health: Recent Progress and Current Challenges (2019) · cites this paper as [31]
In the citing paper
“Third, bright light emitted by SM devices may delay circadian rhythms.36”
From The association between social media use and sleep disturbance among young adults (2016) · cites this paper as [36]
In the citing paper
“For example, increasing light exposure in the natural environment shifts sleep timing earlier [91], while exposure to ambient light at night either from ereaders [92] or urban lighting [93] promotes “lateness.””
From Smoking, screen-based sedentary behavior, and diet associated with habitual sleep duration and chronotype: data from the UK Biobank (2016) · cites this paper as [92]
Citations
Cites
(2007) · Cited by 6,530
Subjective and objective sleepiness in the active individual
Åkerstedt, T., & Gillberg, M. (1990) · International Journal of Neuroscience · doi:10.3109/00207459008994241 · Cited by 3,088 · cited 6×
“Mixed model was also used for comparing KSS score and EEG power with factors Condition, Order, Time (repeated measures in the first hour after awakening), and the Interaction (Condition X Time).”
BackgroundMethodInfluentialAction Spectrum for Melatonin Regulation in Humans: Evidence for a Novel Circadian Photoreceptor
Brainard, G. C., Hanifin, J. P., Greeson, J. M., Byrne, B., Glickman, G., Gerner, E., & Rollag, M. D. (2001) · The Journal of Neuroscience · doi:10.1523/jneurosci.21-16-06405.2001 · Cited by 1,930
Dijk, D., & Czeisler, C. (1995) · The Journal of Neuroscience · doi:10.1523/jneurosci.15-05-03526.1995 · Cited by 1,356 · cited 4×
“The significant phase delay after the LE-eBook condition suggests that the evening light from the LE-eBook phase delayed the circadian clock, delaying the nadir of the circadian rhythm of sleep propensity (2) and thereby resulting in a robust, albeit indirect, effect on morning sleepiness.”
BackgroundInfluentialSelf-citationThapan, K., Arendt, J., & Skene, D. J. (2001) · The Journal of Physiology · doi:10.1111/j.1469-7793.2001.t01-1-00261.x · Cited by 1,320
Measuring and using light in the melanopsin age
Lucas, R. J., Peirson, S. N., Berson, D. M., Brown, T. M., Cooper, H. M., Czeisler, C. A., Figueiro, M. G., Gamlin, P. D., Lockley, S. W., O’Hagan, J. B., et al. (2014) · Trends in Neurosciences · doi:10.1016/j.tins.2013.10.004 · Cited by 1,278 · cited 3×
“In humans, exposure to short-wavelength monochromatic light in the evening has been shown to induce greater circadian and alerting responses than exposure to the same number of photons of longer-wavelength monochromatic light (17–19, 28–34), even though the shorter-wavelength light may have a much lower illuminance le…”
BackgroundMethodInfluentialSelf-citationZeitzer, J. M., Dijk, D., Kronauer, R. E., Brown, E. N., & Czeisler, C. A. (2000) · The Journal of Physiology · doi:10.1111/j.1469-7793.2000.00695.x · Cited by 1,175 · cited 2×
“In humans, exposure to light in the evening and early part of the night, even at low intensity, suppresses the release of the sleep-facilitating hormone melatonin (3–5) and shifts the circadian clock to a later time (3, 6), both of which make it more difficult to fall asleep at night.”
BackgroundSelf-citationCarcinogenicity of shift-work, painting, and fire-fighting
Straif, K., Baan, R., Grosse, Y., Secretan, B., Ghissassi, F. E., Bouvard, V., Altieri, A., Benbrahim-Tallaa, L., & Cogliano, V. (2007) · The Lancet Oncology · doi:10.1016/s1470-2045(07)70373-x · Cited by 1,082 · cited 1×
“10), which has now been classified as a probable carcinogen by the World Health Organization (11, 12).”
BackgroundA Phase Response Curve to Single Bright Light Pulses in Human Subjects
Khalsa, S. B. S., Jewett, M. E., Cajochen, C., & Czeisler, C. A. (2003) · The Journal of Physiology · doi:10.1113/jphysiol.2003.040477 · Cited by 1,040 · cited 2×
“In humans, exposure to light in the evening and early part of the night, even at low intensity, suppresses the release of the sleep-facilitating hormone melatonin (3–5) and shifts the circadian clock to a later time (3, 6), both of which make it more difficult to fall asleep at night.”
BackgroundSelf-citationCajochen, C., Münch, M., Kobialka, S., Kräuchi, K., Steiner, R., Oelhafen, P., Orgül, S., & Wirz-Justice, A. (2005) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2004-0957 · Cited by 939
Research works printed but not linked: 1
- ED Weitzman, CA Czeisler, JC Zimmerman, JM Ronda, The timing of REM sleep and its relation to spontaneous awakening during temporal isolation in man. Sleep Res 9, 280 (1980).
Cited by
Sorted by citations
Twenge, J. M., Cooper, A. B., Joiner, T. E., Duffy, M. E., & Binau, S. G. (2019) · Journal of Abnormal Psychology · doi:10.1037/abn0000410 · Cited by 1,469
Molecular mechanisms and physiological importance of circadian rhythms
Patke, A., Young, M. W., & Axelrod, S. (2020) · Nature Reviews Molecular Cell Biology · doi:10.1038/s41580-019-0179-2 · Cited by 1,388
Circadian rhythm disruption and mental health
Walker, W. H., Walton, J. C., DeVries, A. C., & Nelson, R. J. (2020) · Translational Psychiatry · doi:10.1038/s41398-020-0694-0 · Cited by 1,030
Neural Circuitry of Wakefulness and Sleep
Scammell, T. E., Arrigoni, E., & Lipton, J. O. (2017) · Neuron · doi:10.1016/j.neuron.2017.01.014 · Cited by 966
Touitou, Y., Reinberg, A., & Touitou, D. (2017) · Life Sciences · doi:10.1016/j.lfs.2017.02.008 · Cited by 738
“Even low intensity light, as emitted by recent technologies such as LEDs, computer screens or televisions, mobile phones, and tablets is capable of acting on the clock, thus leading to a phase delay and a slowing of melatonin secretion [21].”
Background
Metadata
- Authors
- Chang, A.-M., Aeschbach, D., Duffy, J. F., & Czeisler, C. A.
- Affiliations
- Brigham and Women's Hospital (US)
- Venue
- Proceedings of the National Academy of Sciences
- Publisher
- National Academy of Sciences
- Published
- 2014-12-22
- Volume
- 112
- Issue
- 4
- Pages
- 1232-1237
- ISSN
- 0027-8424 (ISSN-L)
- 1091-6490
- PMC
- PMC4313820
- OpenAlex
- W2103257619
- Cited by
- 1,430
- References
- 41
- Citations by year
- 2026: 182 · 2025: 170 · 2024: 139 · 2023: 127 · 2022: 119 · 2021: 116 · 2020: 113 · 2019: 127 · 2018: 121 · 2017: 88 · 2016: 67 · 2015: 58 · 2014: 1
- FWCI
- 34.71
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Proceedings of the National Academy of Sciences (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- elib (German Aerospace Center) (acceptedVersion)
- Funders
- HHS | NIH | National Heart, Lung, and Blood Institute (R01HL77453, K01HL115458)
- Topics
- Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and related disorders
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and Work-Related Fatigue
- Keywords
- sleep, circadian rhythm, melatonin suppression, circadian phase delay, alertness, evening light exposure, printed books, bedtime, sleep latency, sleepiness
- MeSH terms
- Adult, Circadian Rhythm, Female, Humans, Lighting, Male, Melatonin, Reading, Sleep, Sleep Wake Disorders
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-09-30, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).
A second model labelled each claim on 2026-09-30 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
Cited sources are checked with a language model’s help (gpt-6-sol).
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
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