Better sleep is on Cleveland Clinic’s list of hot tub benefits. Of the claims on that list, it has some of the better research behind it, though not from hot tub studies.
This article covers what the research found and the timing it points to. It sits under our overview of hot tub benefits. It is general information, not medical advice.
Short answer: a 2019 meta-analysis found that a warm bath or shower 1 to 2 hours before bed, for as little as 10 minutes, was linked to falling asleep faster and better self-rated sleep. Cleveland Clinic’s expert suggests getting out of a hot tub 1 to 1.5 hours before bed. The studies used water up to 108.5°F; a hot tub should stay at or below 104°F.
What the 2019 meta-analysis found
A 2019 review in Sleep Medicine Reviews looked at studies of “passive body heating” by warm shower or bath. The authors found 17 eligible studies and pooled 13 of them.
Water at 40 to 42.5°C (104 to 108.5°F) was linked to:
- Better self-rated sleep quality
- Better sleep efficiency
- Falling asleep faster, when the soak was 1 to 2 hours before bedtime, even for 10 minutes
The authors call the research base scarce, and say more work is needed on the best timing, duration, and mechanism.
Why timing matters
The authors’ explanation: warm water raises blood flow to the palms and soles, which speeds the natural fall in core body temperature that comes before sleep.
Cleveland Clinic’s 2025 article gives the same picture. It says the body’s temperature drop after heating up and then cooling can prompt sleep, and its expert, Melissa Young, MD, recommends getting out of the tub “an hour to an hour and a half” before bed.
| Source | Timing |
|---|---|
| 2019 meta-analysis | Soak 1 to 2 hours before bedtime |
| Cleveland Clinic, 2025 | Get out 1 to 1.5 hours before bed |
The temperature catch
Here’s what the headline won’t tell you. The study range runs up to 108.5°F. The Consumer Product Safety Commission says hot tub water should never exceed 104°F, and Cleveland Clinic says to keep it below 104°F. So the sleep studies don’t tell you to run a spa hotter.
Cleveland Clinic also says more than 15 minutes in a hot tub could lead to heat-related swelling, stiffness, and aches, and longer soaks may cause a drop in blood pressure, dizziness, or fainting.
Alcohol and a late soak
Cleveland Clinic says hot tubs and alcohol “don’t mix at all.” CPSC’s 1979 warning says drinking raises the drowning risk and can cause drowsiness that leads to unconsciousness. It also says people taking medicines that cause drowsiness should not use hot tubs, which matters if you take a sleep aid.
My rule of thumb: make the evening soak the last warm thing you do, then give yourself an hour to cool down before bed.
Bottom line: a warm soak an hour or two before bed is one of the better-supported hot tub benefits, even if the evidence comes from baths. Keep the water at or below 104°F and skip the drink. For the other claims, see the hot tub benefits overview linked above.
Sources
- Haghayegh S, et al., “Before-bedtime passive body heating by warm shower or bath to improve sleep: A systematic review and meta-analysis,” Sleep Medicine Reviews, 2019 (abstract): pubmed.ncbi.nlm.nih.gov
- Cleveland Clinic, “Soak It In: How Hot Tubs Can Boost Your Health,” November 17, 2025: health.clevelandclinic.org
- U.S. Consumer Product Safety Commission, “CPSC Warns Of Hot Tub Temperatures,” release 79-071, December 31, 1979: cpsc.gov