Evening Light Intensity and Phase Delay of the Circadian Clock in Early Childhood
Open accessAbstract
Late sleep timing is prevalent in early childhood and a risk factor for poor behavioral and health outcomes. Sleep timing is influenced by the phase of the circadian clock, with later circadian timing linked to delayed sleep onset in young children. Light is the strongest zeitgeber of circadian timing and, in adults, evening light produces circadian phase delay in an intensity-dependent manner. The intensity-dependent circadian phase-shifting response to evening light in children, however, is currently unknown. In the present study, 33 healthy, good-sleeping children aged 3.0 to 4.9 years (M = 4.14 years, 39% male) completed a 10-day between-subjects protocol. Following 7 days of a stable sleep schedule, an in-home dim-light circadian assessment was performed. Children remained in dim-light across 3 days (55 h), with salivary melatonin collected in regular intervals throughout each evening. Phase-shifting effects of light exposure were determined via changes in the timing of the dim-light melatonin onset (DLMO) prior to (Day 8) and following (Day 10) a light exposure stimulus. On Day 9, children were exposed to a 1 h light stimulus in the hour before their habitual bedtime. Each child was randomly assigned to one intensity between 5 and 5000 lux (4.5-3276 melanopic EDI). Across light intensities, children showed significant circadian phase delays, with an average phase delay of 56.1 min (SD = 33.6 min), and large inter-individual variability. No relationship between light intensity and magnitude of the phase shift was observed. However, a greater percentage of melatonin suppression during the light exposure was associated with a greater phase delay ( r = −0.73, p < 0.01). These findings demonstrate that some young children may be highly sensitive to light exposure in the hour before bedtime and suggest that the home lighting environment and its impact on circadian timing should be considered a possible contributor to behavioral sleep difficulties.
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In a randomized experimental study, one hour of light exposure before bedtime delayed preschoolers' circadian phase by about 56 minutes on average.
“In a randomized experimental study, 1 hour of light exposure before bedtime resulted in preschoolers having average delayed circadian phase of about 56 minutes.207”
From Digital Ecosystems, Children, and Adolescents: Technical Report (2026) · cites this paper as [207]
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Cites
Zeitzer, 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 · see citing works
A 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 · see citing works
Behavioral treatment of bedtime problems and night wakings in infants and young children
(2006) · Sleep · doi:10.1093/sleep/29.10.1263 · Cited by 849 · see citing works
High Sensitivity of the Human Circadian Melatonin Rhythm to Resetting by Short Wavelength Light
Lockley, S. W., Brainard, G. C., & Czeisler, C. A. (2003) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2003-030570 · Cited by 782 · see citing works
Gregory, A., & O'Connor, T. (2002) · Journal of the American Academy of Child and Adolescent Psychiatry · doi:10.1097/00004583-200208000-00015 · Cited by 681 · see citing works
Dose-response relationships for resetting of human circadian clock by light
Boivin, D. B., Duffy, J. F., Kronauer, R. E., & Czeisler, C. A. (1996) · Nature · doi:10.1038/379540a0 · Cited by 559 · see citing works
Entrainment of the human circadian system by light
Duffy, J. F., & Wright, K. P. (2005) · Journal of Biological Rhythms · doi:10.1177/0748730405277983 · Cited by 515 · see citing works
Self-citationGregory, A. M., Caspi, A., Eley, T. C., Moffitt, T. E., O’Connor, T. G., & Poulton, R. (2005) · Journal of Abnormal Child Psychology · doi:10.1007/s10802-005-1824-0 · Cited by 479 · see citing works
Gooley, J. J., Rajaratnam, S. M. W., Brainard, G. C., Kronauer, R. E., Czeisler, C. A., & Lockley, S. W. (2010) · Science Translational Medicine · doi:10.1126/scitranslmed.3000741 · Cited by 447 · see citing works
Classification and Epidemiology of Childhood Sleep Disorders
Owens, J. A. (2008) · Primary Care Clinics in Office Practice · doi:10.1016/j.pop.2008.06.003 · Cited by 318 · see citing works
An Approach to Studying Circadian Rhythms of Adolescent Humans
Carskadon, M. A., Acebo, C., Richardson, G. S., Tate, B. A., & Seifer, R. (1997) · Journal of Biological Rhythms · doi:10.1177/074873049701200309 · Cited by 301 · see citing works
Human phase response curve to a 1 h pulse of bright white light
Hilaire, M. A. S., Gooley, J. J., Khalsa, S. B. S., Kronauer, R. E., Czeisler, C. A., & Lockley, S. W. (2012) · The Journal of Physiology · doi:10.1113/jphysiol.2012.227892 · Cited by 277 · see citing works
Sleep and Behavior Problems Among Preschoolers
Lavigne, J. V., Arend, R. A., Rosenbaum, D. L., Smith, A. W., Weissbluth, M., Binns, H. J., & Christoffel, K. K. (1999) · Journal of Developmental & Behavioral Pediatrics · doi:10.1097/00004703-199906000-00005 · Cited by 267 · see citing works
The human circadian system adapts to prior photic history
Chang, A., Scheer, F. A. J. L., & Czeisler, C. A. (2011) · The Journal of Physiology · doi:10.1113/jphysiol.2010.201194 · Cited by 263 · see citing works
Li, L., Zhang, S., Huang, Y., & Chen, K. (2017) · Journal of Paediatrics and Child Health · doi:10.1111/jpc.13434 · Cited by 224 · see citing works
Wright, K. P., Gronfier, C., Duffy, J. F., & Czeisler, C. A. (2005) · Journal of Biological Rhythms · doi:10.1177/0748730404274265 · Cited by 217 · see citing works
Self-citationGronfier, C., Wright, K. P., Kronauer, R. E., Jewett, M. E., & Czeisler, C. A. (2004) · American Journal of Physiology-Endocrinology and Metabolism · doi:10.1152/ajpendo.00385.2003 · Cited by 212 · see citing works
Self-citationInfluence of light at night on melatonin suppression in children
Higuchi, S., Nagafuchi, Y., Lee, S.-I., & Harada, T. (2014) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2014-1629 · Cited by 200 · see citing works
Posture influences melatonin concentrations in plasma and saliva in humans
Deacon, S., & Arendt, J. (1994) · Neuroscience Letters · doi:10.1016/0304-3940(94)91059-6 · Cited by 185 · see citing works
Sleep Patterns and Sleep Disruptions in Kindergarten Children
Tikotzky, L., & Sadeh, A. (2001) · Journal of Clinical Child & Adolescent Psychology · doi:10.1207/s15374424jccp3004_13 · Cited by 174 · see citing works
Jewett, M. E., Rimmer, D. W., Duffy, J. F., Klerman, E. B., Kronauer, R. E., & Czeisler, C. A. (1997) · American Journal of Physiology-Regulatory, Integrative and Comparative Physiology · doi:10.1152/ajpregu.1997.273.5.r1800 · Cited by 168 · see citing works
Etiologies of Associations Between Childhood Sleep and Behavioral Problems in a Large Twin Sample
Gregory, A. M., Eley, T. C., O’Connor, T. G., & Plomin, R. J. (2004) · Journal of the American Academy of Child & Adolescent Psychiatry · doi:10.1097/01.chi/0000122798.47863.a5 · Cited by 164 · see citing works
Individual differences in light sensitivity affect sleep and circadian rhythms
Chellappa, S. L. (2021) · Sleep · doi:10.1093/sleep/zsaa214 · Cited by 163 · see citing works
The dim light melatonin onset following fixed and free sleep schedules
Burgess, H. J., & Eastman, C. I. (2005) · Journal of Sleep Research · doi:10.1111/j.1365-2869.2005.00470.x · Cited by 156 · see citing works
Sleep and Obesity in Preschool Children
Jiang, F., Zhu, S., Yan, C., Jin, X., Bandla, H., & Shen, X. (2009) · The Journal of Pediatrics · doi:10.1016/j.jpeds.2008.12.043 · Cited by 140 · see citing works
Sleep deprivation and neurobehavioral functioning in children
Maski, K. P., & Kothare, S. V. (2013) · International Journal of Psychophysiology · doi:10.1016/j.ijpsycho.2013.06.019 · Cited by 129 · see citing works
Chronotype is associated with the timing of the circadian clock and sleep in toddlers
Simpkin, C. T., Jenni, O. G., Carskadon, M. A., Wright, K. P., Akacem, L. D., Garlo, K. G., & LeBourgeois, M. K. (2014) · Journal of Sleep Research · doi:10.1111/jsr.12142 · Cited by 96 · see citing works
Self-citationSleep and bedtime behavior in preschool-aged children.
Beltramini, A. U., & Hertzig, M. E. (1983) · PubMed · Cited by 92 · see citing works
Circadian Phase and Its Relationship to Nighttime Sleep in Toddlers
LeBourgeois, M. K., Carskadon, M. A., Akacem, L. D., Simpkin, C. T., Wright, K. P., Achermann, P., & Jenni, O. G. (2013) · Journal of Biological Rhythms · doi:10.1177/0748730413506543 · Cited by 88 · see citing works
Self-citationSleep problems and daytime tiredness in Finnish preschool‐aged children‐a community survey
Simola, P. E., Niskakangas, M., Liukkonen, K., Virkkula, P., Pitkäranta, A., Kirjavainen, T., & Aronen, E. T. (2010) · Child Care Health and Development · doi:10.1111/j.1365-2214.2010.01112.x · Cited by 81 · see citing works
Sleep and Bedtime Behavior in Preschool-Aged Children
Beltramini, A. U., & Hertzig, M. E. (1983) · PEDIATRICS · doi:10.1542/peds.71.2.153 · Cited by 75 · see citing works
Sensitivity of the circadian system to evening bright light in preschool-age children
Akacem, L. D., Wright, K. P., & LeBourgeois, M. K. (2018) · Physiological Reports · doi:10.14814/phy2.13617 · Cited by 70 · see citing works
Self-citationHuman Adolescent Phase Response Curves to Bright White Light
Crowley, S. J., & Eastman, C. I. (2017) · Journal of Biological Rhythms · doi:10.1177/0748730417713423 · Cited by 69 · see citing works
High sensitivity of melatonin suppression response to evening light in preschool‐aged children
Hartstein, L. E., Behn, C. D., Akacem, L. D., Stack, N., Wright, K. P., & LeBourgeois, M. K. (2022) · Journal of Pineal Research · doi:10.1111/jpi.12780 · Cited by 64 · see citing works
Self-citationFunctional decoupling of melatonin suppression and circadian phase resetting in humans
Rahman, S. A., St Hilaire, M. A., Gronfier, C., Chang, A., Santhi, N., Czeisler, C. A., Klerman, E. B., & Lockley, S. W. (2018) · The Journal of Physiology · doi:10.1113/jp275501 · Cited by 58 · see citing works
Akacem, L. D., Wright, K. P., & LeBourgeois, M. K. (2016) · Neurobiology of Sleep and Circadian Rhythms · doi:10.1016/j.nbscr.2016.11.002 · Cited by 45 · see citing works
Self-citationFree‐running circadian period in adolescents and adults
Crowley, S. J., & Eastman, C. I. (2018) · Journal of Sleep Research · doi:10.1111/jsr.12678 · Cited by 44 · see citing works
Eto, T., Ohashi, M., Nagata, K., Shin, N., Motomura, Y., & Higuchi, S. (2021) · Ophthalmic and Physiological Optics · doi:10.1111/opo.12809 · Cited by 41 · see citing works
LeBourgeois, M. K., Wright, K. P., LeBourgeois, H. B., & Jenni, O. G. (2013) · Mind Brain and Education · doi:10.1111/mbe.12032 · Cited by 34 · see citing works
Self-citationChapter 50 Daytime behavioral correlates of awakenings and bedtime resistance in preschool children
Bruni, O., Reto, F. L., Miano, S., & Ottaviano, S. (2000) · Supplements to Clinical neurophysiology · doi:10.1016/s1567-424x(09)70181-3 · Cited by 22 · see citing works
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Sleep Across the Lifespan: A Neurobehavioral Perspective
Simon, K. C. N. S., Cadle, C. E., Shuster, A. E., & Malerba, P. (2025) · Current Sleep Medicine Reports · doi:10.1007/s40675-025-00322-2 · Cited by 31 · see citing works
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Westwood, E., Smith, S. S., Mann, D., Pattinson, C. L., Allan, A. C., & Staton, S. (2023) · Journal of Environmental Psychology · doi:10.1016/j.jenvp.2023.102062 · Cited by 21 · see citing works
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Naveed, M., Chao, O. Y.-H., Hill, J. W., Yang, Y., Huston, J. P., & Cao, R. (2023) · Neuroscience & Biobehavioral Reviews · doi:10.1016/j.neubiorev.2023.105523 · Cited by 15 · see citing works
Abid, R., Ammar, A., Maaloul, R., Boudaya, M., Souissi, N., & Hammouda, O. (2024) · European Journal of Investigation in Health Psychology and Education · doi:10.3390/ejihpe14040055 · Cited by 14 · see citing works
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Li, Z., Fu, B., Wei, A., Wu, Y., Huang, M., Zhang, E., Cui, B., Wang, B. J., & Peng, H. (2023) · Life Sciences · doi:10.1016/j.lfs.2023.121765 · Cited by 12 · see citing works
Digital Ecosystems, Children, and Adolescents: Technical Report
Munzer, T., Milkovich, L. M., Madigan, S., Tomopoulos, S., Parga-Belinkie, J., Ajumobi, T., Cross, C., Gerwin, R., Council on Communications and Media, Radesky, J., et al. (2026) · Pediatrics · doi:10.1542/peds.2025-075321 · Cited by 14 · see citing works
Hansen, M., Simon, K. R., He, X., Steele, N. C., Thomas, M. L., Noble, K. G., & Merz, E. C. (2024) · Frontiers in Psychiatry · doi:10.3389/fpsyt.2024.1373546 · Cited by 11 · see citing works
Xu, Y.-X., Huang, Y., Ding, W.-Q., Zhou, Y., Shen, Y., Wan, Y., Su, P., Tao, F., & Sun, Y. (2024) · Environmental Research · doi:10.1016/j.envres.2024.118657 · Cited by 10 · see citing works
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Kracht, C. L., Bolamperti, G., Breeden, R., Crocker, M., Christifano, D. N., Gibler, R. C., Gyllenborg, G., Johnson, P. R. A., Lovell, J., Mathews, L., et al. (2026) · JAMA Network Open · doi:10.1001/jamanetworkopen.2025.51958 · Cited by 9 · see citing works
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- Authors
- Hartstein, L. E., Diniz Behn, C., Wright, K. P., Akacem, L. D., Stowe, S. R., & LeBourgeois, M. K.
- Affiliations
- University of Colorado Boulder (US)
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, Colorado
- National Center for Advancing Translational Sciences (US)
- Colorado School of Mines (US)
- Corresponding author
- LeBourgeois, Monique K.
- ORCID
- Venue
- Journal of Biological Rhythms
- Publisher
- SAGE Publications
- Published
- 2022-11-22
- Volume
- 38
- Issue
- 1
- Pages
- 77-86
- ISSN
- 0748-7304 (ISSN-L)
- 1552-4531
- PMC
- PMC11302507
- OpenAlex
- W4309714990
- Cited by
- 32
- References
- 40
- Citations by year
- 2026: 12 · 2025: 5 · 2024: 9 · 2023: 6
- FWCI
- 2.64
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Journal of Biological Rhythms (publishedVersion)
- PubMed (publishedVersion)
- PubMed Central (acceptedVersion)
- Funders
- National Heart, Lung, and Blood Institute (T32-HL149646)
- Eunice Kennedy Shriver National Institute of Child Health and Human Development (R01-HD087707)
- The University of Colorado Boulder Biological Sciences Initiative Scholars Program
- The University of Colorado Boulder Undergraduate Research Opportunities Program
- 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
- circadian clock, circadian phase delay, evening light exposure, light intensity, children, dim light melatonin onset, melatonin suppression, sleep timing, bedtime, zeitgebers
- MeSH terms
- Child, Preschool, Circadian Rhythm, Female, Humans, Male, Melatonin, Sleep, Sleep Disorders, Circadian Rhythm, Circadian Clocks
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