Effects of skin surface temperature on photoplethysmograph
Open accessAbstract
Photoplethysmograph (PPG) has been widely used to investigate various cardiovascular conditions. Previous studies demonstrated effects of temperature of the measurement environment; however, an integrated evaluation has not been established in environments with gradual air temperature variation. The purpose of this study is to investigate variations and relationships of blood pressure (BP), PPG and cardiovascular parameters such as heart rate (HR), stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR), by changing skin surface temperature (SST). Local mild cooling and heating was conducted on 16 healthy subjects. The results showed that local SST changes affected Finometer blood pressures (Finger BP), PPG components and TPR, but not the oscillometric blood pressure (Central BP), HR, SV and CO, and indicated that temperature must be maintained and monitored to reliably evaluate cardiovascular conditions in temperature‐varying environments.
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Written from the paper’s full text.
TL;DR
In 16 healthy subjects, local skin cooling/heating changed skin surface temperature and significantly affected Finometer finger blood pressure, PPG components, and total peripheral resistance, while oscillometric central BP, HR, SV, and CO were not consistently affected. The authors conclude that temperature must be maintained and monitored for reliable PPG-based cardiovascular evaluation.
Key findings
- Cooling: chamber air temperature decreased by 9.4±0.7°C; left SST decreased by 8.8±2.5°C and right SST by 1.6±1.4°C. Finometer SBP increased by 10±9.0 mmHg and DBP by 7±6.0 mmHg (p<0.01), while oscillometric SBP/DBP did not change significantly.
- Heating: chamber air temperature increased by 19.5±1.2°C; left SST increased by 6.3±2.6°C and right SST by 1.1±1.7°C. Finometer SBP increased by 6±7.8 mmHg and DBP by 5±6.2 mmHg (p<0.01); oscillometric SBP did not change significantly, and the text reports oscillometric DBP significantly increased although Table 2 shows a −5±7.1 mmHg difference.
- PPG DC foot and DC peak were significantly negatively correlated with SST (r ranges −0.634 to −0.980 and −0.594 to −0.980, p<0.01); PPG AC component was positively correlated with SST (r 0.108 to 0.941), significant in 12 of 16 subjects.
- TPR showed significant negative correlations with SST (r −0.443 to −0.904, p<0.01), while HR, SV, and CO correlations were significant in individuals but not fixed across all subjects.
Methods
- Pilot experimental study using local mild cooling and heating in a temperature-controlled chamber; each participant was tested under both heating and cooling conditions.
- Sixteen healthy participants (age 26±2.1 years; BMI 23±4.8 kg/m²; resting HR 73±8.8 beats/min), not undergoing drug treatment or experiencing Raynaud’s phenomenon; they refrained from smoking, alcohol, and extreme exercise for 12 h and caffeine for 4 h before the experiment.
- PPG was measured on both index fingers, Finometer on the left middle finger, oscillometric BP on the right upper arm, and SST by contact sensors on both fourth fingers plus infrared thermography; analyses used paired-samples tests and correlations in SPSS 12.0.
Limitations
- Stated by the paper: small number of subjects and no consideration of gender differences.
- Evident from the text: this is a pilot study with a short 20-min protocol, individual variability in SST and cardiovascular responses, and an apparent inconsistency in the heating oscillometric DBP result (text says increased; Table 2 shows a decrease).
Model-written summary. Check it against the paper before relying on it.
Integrity signals
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Cites
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Claims the paper makes
0 of 7 cited sources checked · 0 supported · 0 flagged
- Findingown data
Local skin surface temperature (SST) changes affected Finometer blood pressures (Finger BP), PPG components and total peripheral resistance (TPR).
“The results showed that local SST changes affected Finometer blood pressures (Finger BP), PPG components and TPR, but not the oscillometric blood pressure (Central BP), HR, SV and CO, and indicated that temperature must be maintained and monitored to reliably evaluate cardiovascular conditions in temperature-varying environments.”
- Also stated in: § 5. CONCLUSION · boosted
“Changes in cardiovascular characteristics and peripheral vessels by SST change were demonstrated.”
- Also stated in: § 4. DISCUSSION · plain
“The oscillometric BP was not affected but Finometer BP, which employed PPG estimation method, was affected by changes in SST because changes in blood flow and blood vessels were generated by the temperature adaptation mechanism.”
Quote in the paperSubstantial claim - Also stated in: § 5. CONCLUSION · boosted
- Findingown data
During the cooling period, left SST decreased by 8.8±2.5°C (p<0.01).
“With the chamber temperature decrease, the left SST (-8.8±2.5˚C,p<0.01) and the right SST (-1.6±1.4,p<0.01) were significantly decreased.”
Quote in the paperSubstantial claim - Findingnone given
SST thermogram changes were identical to SST sensor changes.
“SST thermogram changes were identical to SST sensor changes.”
Quote in the paperNot a substantial claim - Findingown data
During the heating period, Finometer DBP increased by 5±6.2 mmHg (p<0.01).
“Both Finometer systolic blood pressure (SBP) (6±7.8mmHg,p<0.01) and diastolic blood pressure (DBP) (5±6.2mmHg,p<0.01) significantly increased.”
Quote in the paperNot a substantial claim - Findingown data
During the cooling period, Finometer diastolic blood pressure (DBP) increased by 7±6.0 mmHg (p<0.01).
“Both Finometer systolic blood pressure (SBP) (10±9.0mmHg,p<0.01) and diastolic blood pressure (DBP) (7±6.0mmHg,p<0.01) significantly increased.”
Quote in the paperNot a substantial claim
- Findingown data
In the initial 10 min, similar BP values were obtained in both oscillometric and Finometer data.
“In the initial 10 min, similar values of BP were obtained in both the oscillometric and Finometer data; however, the values were significantly different when the chamber air temperature was changed.”
Quote in the paperSubstantial claim - Findingown data
During the heating period, Finometer SBP increased by 6±7.8 mmHg (p<0.01).
“Both Finometer systolic blood pressure (SBP) (6±7.8mmHg,p<0.01) and diastolic blood pressure (DBP) (5±6.2mmHg,p<0.01) significantly increased.”
Quote in the paperNot a substantial claim - Findingown data
During the heating period, right SST increased by 1.1±1.7°C (p<0.05).
“With the chamber temperature increase, the left SST (6.3±2.6˚C,p<0.01) and the right SST (1.1±1.7˚C,p<0.05) were significantly increased.”
Quote in the paperNot a substantial claim - Findingown data
HR, SV, and CO correlations with SST were not fixed (consistent) for all subjects.
“Correlations between HR and SST, between SV and SST, and between CO and SST were significant in individuals, but these were not fixed correlations for all subjects.”
Quote in the paperSubstantial claim - Findingreasoning
The overall data trend was not affected by individual vasoconstrictions and vasodilatations.
“The overall data trend was not affected by these results.”
Quote in the paperNot a substantial claim - Findingown data
DC peak had significant negative correlations with SST ranging from -0.594 to -0.980.
“Significant negative correlations (p<0.01) between DC components and SST were calculated in ranges between -0.634 and -0.980 for DC foot, and between -0.594 and -0.980 for DC peak.”
Quote in the paperSubstantial claim - Findingown data
The initial 10 min before the heating and cooling periods did not show any significant variation in all parameters.
“The initial 10 min before the heating and cooling periods did not show any significant variation in all parameters.”
Quote in the paperNot a substantial claim - Findingown data
DC foot had significant negative correlations with SST ranging from -0.634 to -0.980.
“Significant negative correlations (p<0.01) between DC components and SST were calculated in ranges between -0.634 and -0.980 for DC foot, and between -0.594 and -0.980 for DC peak.”
Quote in the paperSubstantial claim - Findingreasoning
When chamber air temperature was changed, oscillometric and Finometer BP values were significantly different.
“In the initial 10 min, similar values of BP were obtained in both the oscillometric and Finometer data; however, the values were significantly different when the chamber air temperature was changed.”
Quote in the paperSubstantial claim - Findingown data
During the cooling period, Finometer systolic blood pressure (SBP) increased by 10±9.0 mmHg (p<0.01).
“Both Finometer systolic blood pressure (SBP) (10±9.0mmHg,p<0.01) and diastolic blood pressure (DBP) (7±6.0mmHg,p<0.01) significantly increased.”
Quote in the paperNot a substantial claim - Findingown data
During the heating period, left SST increased by 6.3±2.6°C (p<0.01).
“With the chamber temperature increase, the left SST (6.3±2.6˚C,p<0.01) and the right SST (1.1±1.7˚C,p<0.05) were significantly increased.”
Quote in the paperNot a substantial claim - Findingown data
During the cooling period, right SST decreased by 1.6±1.4°C (p<0.01).
“With the chamber temperature decrease, the left SST (-8.8±2.5˚C,p<0.01) and the right SST (-1.6±1.4,p<0.01) were significantly decreased.”
Quote in the paperNot a substantial claim - Findingreasoning
TPR showed an increasing trend with SST.
“The overall changes in HR, SV, and CO did not show significant correlations with SST, while TPR showed an increasing trend.”
Quote in the paperSubstantial claim - Findingreasoning
In the left hand temperature range between 22°C and 40°C, PPG AC component generally increased.
“In the temperature range between 22˚C and 40˚C of the left hand, PPG DC components were significantly decreased but PPG AC component was generally increased.”
Quote in the paperSubstantial claim - Findingown data
HR, SV, and CO correlations with SST were significant in some individuals.
“Correlations between HR and SST, between SV and SST, and between CO and SST were significant in individuals, but these were not fixed correlations for all subjects.”
Quote in the paperSubstantial claim - Findingown data
During the heating period, oscillometric SBP did not show significant changes.
“Oscillometric DBP also was significantly increased, but Osillometeric SBP did not show significant changes”
Quote in the paperNot a substantial claim - Findingown data
During the heating period, oscillometric DBP significantly increased.
“Oscillometric DBP also was significantly increased, but Osillometeric SBP did not show significant changes”
Quote in the paperNot a substantial claim - Findingown data
During the cooling period, oscillometric SBP and DBP did not show significant changes.
“However, oscillometric SBP and DBP did not show significant changes.”
Quote in the paperNot a substantial claim - Findingnone given
SST of the left hand directly exposed to temperature change in the chamber had faster changes than the right hand outside the chamber.
“SST of the left hand that was directly exposed to temperature change in the chamber had faster changes than the right hand outside the chamber.”
Quote in the paperNot a substantial claim - Findingown data
In the left hand temperature range between 22°C and 40°C, PPG DC components significantly decreased.
“In the temperature range between 22˚C and 40˚C of the left hand, PPG DC components were significantly decreased but PPG AC component was generally increased.”
Quote in the paperSubstantial claim - Interpretationreasoning
Changes in blood flow and blood vessels were generated by the temperature adaptation mechanism, causing Finometer BP changes.
“The oscillometric BP was not affected but Finometer BP, which employed PPG estimation method, was affected by changes in SST because changes in blood flow and blood vessels were generated by the temperature adaptation mechanism.”
Quote in the paperSubstantial claim - Interpretationcitation
Reduction ratios in each individual were not identical due to individual physiological differences.
“However, reduction ratios in each individual were not identical due to individual physiological differences [16].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [16] source
Not checked in the free run.
- Interpretationreasoning
SST gradually changed after a sudden initial change because of the physiological thermo-natural process of the limbs.
“SST gradually changed after a sudden initial change because of the physiological thermo-natural process of the limbs.”
Quote in the paperNot a substantial claim - Interpretationreasoning
Individual vasoconstrictions and vasodilatations were caused by the natural process of individual body temperature control.
“Although some individual vasoconstrictions and vasodilatations appeared, they were caused by the natural process of individual body temperature control.”
Quote in the paperNot a substantial claim - Interpretationown data
This supports the phenomenon of stronger protection against cold than heat.
“This supports the phenomenon of stronger protection against cold than heat [18].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [18] source
Not checked in the free run.
- May combine two claims. 9
- Classified as probably not a substantial claim. 3
- The quote only partly states this claim. 2
May combine two claims.
Findingown dataLocal SST changes did not affect oscillometric blood pressure (Central BP), heart rate (HR), stroke volume (SV) and cardiac output (CO).
“The results showed that local SST changes affected Finometer blood pressures (Finger BP), PPG components and TPR, but not the oscillometric blood pressure (Central BP), HR, SV and CO, and indicated that temperature must be maintained and monitored to reliably evaluate cardiovascular conditions in temperature-varying environments.”
- Also stated in: § 4. DISCUSSION · plain
“The oscillometric BP was not affected but Finometer BP, which employed PPG estimation method, was affected by changes in SST because changes in blood flow and blood vessels were generated by the temperature adaptation mechanism.”
- Also stated in: § 3.1. BPs and Temperatures · plain
“However, oscillometric SBP and DBP did not show significant changes.”
Quote in the paperSubstantial claim- Also stated in: § 4. DISCUSSION · plain
Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based).
Findingown dataDuring the cooling period, the chamber air temperature decreased by 9.4±0.7°C (p<0.01).
“During the cooling period, the chamber air temperature was decreased to -9.4±0.7˚C,p < 0.01).”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown dataOverall changes in HR, SV, and CO did not show significant correlations with SST.
“The overall changes in HR, SV, and CO did not show significant correlations with SST, while TPR showed an increasing trend.”
Quote in the paperSubstantial claimProbably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based). The quote only partly states this claim.
Findingown dataDuring the heating period, the chamber air temperature increased by 19.5±1.2°C (p<0.01).
“During the heating period, the chamber air temperature was increased to 19.5±1.2˚C(p<0.01).”
Quote in the paperNot a substantial claimThe quote only partly states this claim.
Findingown dataTPR had significant negative correlations with SST ranging from -0.443 to -0.904.
“Significant negative correlations (p<0.01) were calculated in the range between - 0.443 and -0.904.”
Quote in the paperSubstantial claimMay combine two claims.
PremisecitationA previous study demonstrated that the data of noncooled right hand did not significantly change, but could demonstrate a similar decreasing trend.
“A previous study [17] demonstrated that the data of noncooled right hand did not significantly change, but could demonstrate a similar decreasing trend.”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [17]
Not checked in the free run.
May combine two claims.
PremisecitationFour Finometer cardiovascular parameters show only changes in the entire body but not local changes.
“Four Finometer cardiovascular parameters show only changes in the entire body but not local changes [19].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [19]
Not checked in the free run.
May combine two claims.
InterpretationcitationThis result demonstrated that local contraction of blood vessels due to local changes in SST caused changes in the total cardiovascular resistance because the hands have functional importance and excellent control of heat loss.
“This result demonstrated that local contraction of blood vessels due to local changes in SST caused changes in the total cardiovascular resistance because the hands have functional importance and excellent control of heat loss [16,18].”
Quote in the paperSubstantial claim0 of 2 sources checked- cites [16]
Not checked in the free run.
- cites [18]
Not checked in the free run.
May combine two claims.
InterpretationreasoningThe results of the present experiments demonstrated good agreement with the above phenomenon for the cooling process, but weak agreement for the heating process.
“The results of the present experiments demonstrated good agreement with the above phenomenon for the cooling process, but weak agreement for the heating process.”
Quote in the paperSubstantial claim- Rests on an assumption: Cooling of the blood vessel walls causes the loss of contractive capacity, while heating increases its capacity.
May combine two claims.
InterpretationreasoningAlthough the cooling period did not affect the right hand directly, the nonexperimental hand was affected by the mechanism of body temperature control, so correlated results were produced.
“Although the cooling period did not affect the right hand directly, the nonexperimental hand was affected by the mechanism of body temperature control, so correlated results were produced.”
Quote in the paperNot a substantial claimMay combine two claims.
InterpretationcitationThe results also reflected that the PPG component changes were linked to changes in the body temperature and the theory that maintenance of body temperature under the increase and decrease of heat loss was mainly achieved through the blood flow control.
“The results also reflected that the PPG component changes were linked to changes in the body temperature and the theory that maintenance of body temperature under the increase and decrease of heat loss was mainly achieved through the blood flow control [16].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [16]
Not checked in the free run.
Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.
Study design and conductnone givenLimitations of this pilot study include the small number of subjects and not considering the gender difference.
“Limitations of this pilot study include the small number of subjects and not considering the gender difference.”
Quote in the paperNot a substantial claim
The authors state this as an assumption.
All fingers have similar SST distributions.
“this comparison was performed under the assumption that all fingers have similar SST distributions.”
The paper relies on this without support.
Cooling of the blood vessel walls causes the loss of contractive capacity, while heating increases its capacity.
“It is well known that cooling of the blood vessel walls causes the loss of contractive capacity, while heating increases its capacity.”
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?
Local skin surface temperature changes affect PPG components.
“Jeong et al. found that local skin surface temperature changes affect PPG components of 16 healthy subjects aged 23–30 years (26 ± 2.1) and BMI ranging between 20 and 26 (23 ± 4.8), hence recommending that temperature be monitored in order to reliably evaluate cardiovascular parameters [158].”
From Sources of inaccuracy in photoplethysmography for continuous cardiovascular monitoring (2021) · cites this paper as [158]
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
Each contradiction between two passages listed here was confirmed by an independent check.
Abstract says oscillometric BP was unaffected despite a significant DBP change
MajorThe abstract says SST changes did not affect oscillometric blood pressure, whereas the results report a significant change in oscillometric DBP during heating.
“but not the oscillometric blood pressure (Central BP)”
“Oscillometric DBP also was significantly increased”
Heating-related oscillometric DBP is described as increasing but decreases in the table
MinorThe results say oscillometric DBP significantly increased during heating, but Table 2 reports a fall from 76 to 71 mmHg, with an after-minus-before difference of −5 mmHg.
“Oscillometric DBP also was significantly increased”
“DBP 76±14.6 71±11.6 -5±7.1 -2.89 *”
Reported TPR correlation range includes a result not marked p<0.01
MinorThe text describes the full TPR correlation range as significant at p<0.01. Its endpoint of −0.443 is marked with one asterisk in Table 4, which the table defines as p<0.05 rather than p<0.01.
“Significant negative correlations (p<0.01) were calculated in the range between - 0.443 and -0.904.”
“11 0.840 ** -0.488 * 0.107 0.626 -0.443 * 14”
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- Authors
- Jeong, I. C., Yoon, H., Kang, H., & Yeom, H.
- Affiliations
- Johns Hopkins University (US)
- Korea Advanced Institute of Science and Technology (KR)
- Eulji University (KR)
- Venue
- Journal of Healthcare Engineering
- Publisher
- Wiley
- Published
- 2014-01
- Volume
- 5
- Issue
- 4
- Pages
- 429-438
- ISSN
- 2040-2295 (ISSN-L)
- 2040-2309
- OpenAlex
- W2015455093
- Semantic Scholar
- 64850312f419bad43dae115608154a12c2d39829
- Cited by
- 33
- References
- 19
- Citations by year
- 2026: 3 · 2025: 4 · 2024: 5 · 2023: 6 · 2022: 3 · 2021: 5 · 2020: 2 · 2019: 3 · 2018: 1 · 2017: 1
- FWCI
- 0.17
- Type
- journal article
- Language
- en
- Open access
- hybrid
- doi.org
- Licence
- Locations
- Journal of Healthcare Engineering (publishedVersion, cc-by)
- PubMed (publishedVersion)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
- Funders
- Eulji University
- Ministry of Trade, Industry and Energy (2013-02-01)
- Topics
- Physical Sciences › Engineering › Biomedical Engineering › Non-Invasive Vital Sign Monitoring
- Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Heart Rate Variability and Autonomic Control
- Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Cardiovascular Health and Disease Prevention
- Keywords
- photoplethysmography, skin surface temperature, blood pressure, finger blood pressure, oscillometric blood pressure, heart rate, stroke volume, cardiac output, systemic vascular resistance, cardiovascular monitoring
- MeSH terms
- Adult, Humans, Skin, Skin Temperature, Vasoconstriction, Vasodilation, Photoplethysmography, Young Adult
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