Dark Showering: The Sleep Trend Explained
- Shahab Haghayegh, phd, is an instructor in anesthesia in the division of sleep medicine at Harvard Medical School in Boston.
- Taking a bath 1 to 2 hours before bedtime may improve sleep quality and reduce the time it takes to fall asleep.
- A small study, referenced in reporting on Haghayegh's work, indicated positive results with this timing.
Shahab Haghayegh and Sleep Research at Harvard Medical School
Table of Contents
Shahab Haghayegh, phd, is an instructor in anesthesia in the division of sleep medicine at Harvard Medical School in Boston. Recent research explores the potential benefits of pre-bedtime bathing for improved sleep,though further investigation is needed too determine optimal timing and duration.
The potential Benefits of Pre-Bedtime Bathing
Taking a bath 1 to 2 hours before bedtime may improve sleep quality and reduce the time it takes to fall asleep. This effect is likely due to the body’s thermoregulatory response to bathing, which can promote relaxation and drowsiness.
A small study, referenced in reporting on Haghayegh’s work, indicated positive results with this timing. The physiological mechanism involves a post-bath drop in core body temperature, signaling the body that it’s time for sleep.
Such as, a study published in the journal Sleep Medicine in 2019 found that participants who took a warm bath 90 minutes before bedtime experienced improvements in sleep onset latency and overall sleep efficiency. [1]
Current Research Status (as of January 14,2026)
As of January 14,2026,research on the optimal timing and duration of pre-bedtime bathing remains ongoing.While initial studies suggest a benefit, larger and more controlled trials are needed to confirm these findings and establish clear recommendations. There have been no major, publicly released updates to the findings since the initial reporting in late 2023/early 2024.
The National Sleep Foundation continues to recommend establishing a relaxing bedtime routine, and bathing could be a component of that routine for some individuals. [2]
- Harvard Medical School: The academic institution were Shahab Haghayegh conducts research and teaches.
- National Sleep Foundation: A non-profit organization dedicated to improving sleep health and promoting sleep awareness.
[1] Haghayegh, S., et al.(2019). Effects of evening warm bath on sleep: a systematic review and meta-analysis. Sleep Medicine, 68, 126-134.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6827952/
[2] National Sleep Foundation. (n.d.). Sleep Hygiene. Retrieved January 14, 2026, from https://www.thensf.org/sleep-hygiene/