Nocturnal Skin Temperature
Celsius or Fahrenheit
Wrist skin temperature recorded during sleep: minimum, maximum and average, compared against your personal nightly baseline.
Typical optimal range -0.3 - 0.3
Population median 0.1
Key factors
- Room temperature and bedding weight
- Menstrual cycle phase
- Late exercise raising core temperature
What affects this metric
- A hot bath, shower, or sauna before bed raises it for hours.
- Immune response after vaccination raises it for a day or two.
- Illness raises nocturnal temperature above baseline, often before symptoms.
- Alcohol raises it through peripheral vasodilation.
- Room temperature and bedding weight shift the reading.
- Menstrual cycle phase shifts baseline across the month.
References
Peer-reviewed sources supporting the key factors, contributing factors, and typical optimal range shown above.
- Smarr BL, Aschbacher K, Fisher SM, et al.. Feasibility of continuous fever monitoring using wearable devices. Scientific Reports. 2020;10:21640. doi.org/10.1038/s41598-020-78355-6
- Presby DM, Capodilupo ER. Biometrics from a wearable device reveal temporary effects of COVID-19 vaccines on cardiovascular, respiratory, and sleep physiology. Journal of Applied Physiology. 2022;132(2):448–458. doi.org/10.1152/japplphysiol.00420.2021
- Haghayegh S, Khoshnevis S, Smolensky MH, Diller KR, Castriotta RJ. Before-bedtime passive body heating by warm shower or bath to improve sleep: a systematic review and meta-analysis. Sleep Medicine Reviews. 2019;46:124–135. doi.org/10.1016/j.smrv.2019.04.008
- Baker FC, Driver HS. Circadian rhythms, sleep, and the menstrual cycle. Sleep Medicine. 2007;8(6):613–622. doi.org/10.1016/j.sleep.2006.09.011
- Okamoto-Mizuno K, Mizuno K. Effects of thermal environment on sleep and circadian rhythm. Journal of Physiological Anthropology. 2012;31:14. doi.org/10.1186/1880-6805-31-14
This guide is general information, not medical advice. Talk to your clinician about your own results.