Lower blood pressure is on Cleveland Clinic’s list of hot tub benefits. The short-term effect is well described. The long-term claim rests on much less.
This article separates the two. It sits under our overview of hot tub benefits. It is general information, not medical advice.
Short answer: a hot tub lowers your blood pressure while you’re in it, because warm water widens blood vessels. Cleveland Clinic says the effect is temporary, and that soaks over 15 minutes can drop pressure enough to cause dizziness or fainting. Long-term drops have been seen only in a small, supervised lab trial. If you’re treated for high blood pressure, talk to your provider first.
What happens while you soak
Cleveland Clinic’s 2025 article: soaking widens blood vessels and lowers blood pressure. It adds that “the effects are only temporary.” Pressure should return to normal a few minutes after you cool off.
When the drop is the problem
The same article warns that soaks over 15 minutes “may cause a drop in blood pressure, dizziness or fainting.” It applies this to two groups:
| Your blood pressure | What Cleveland Clinic says |
|---|---|
| Treated for high blood pressure | Talk to your provider first |
| Normal or low (hypotension) | Heat can cause lightheadedness and fainting; the risk can rise with age but affects younger people too |
It also says dizziness or a headache can signal dehydration or low blood pressure, and to get out if you feel too hot, dizzy, or develop a headache.
What longer-term studies found
A 2016 trial in the Journal of Physiology put 10 sedentary young adults in a 40.5°C (104.9°F) bath, 4 to 5 times a week for 8 weeks. Each session held their core temperature at 38.5°C or higher for 60 minutes. Compared with 10 people in neutral-temperature water, they had lower mean arterial and diastolic blood pressure, and better artery function.
Here’s what the ad won’t tell you. That’s 20 people, young and sedentary, under supervision, soaking 4 times longer than Cleveland Clinic’s 15-minute guidance. It doesn’t show what home soaking does.
A 2020 study in Heart followed 30,076 Japanese adults for up to 19 years and found almost-daily tub bathing linked to a 28% lower risk of cardiovascular disease. That’s an association in traditional Japanese baths. The abstract doesn’t report blood pressure as an outcome.
What to take from it
My rule of thumb: count the soak’s blood pressure drop as a reason to keep sessions short, not as a treatment. Cleveland Clinic’s broader point stands: a hot tub “doesn’t replace the need for a heart-healthy diet and regular exercise.”
Bottom line: a hot tub lowers blood pressure for as long as you’re in it, and that can tip into dizziness on long soaks. Lasting effects are unproven outside a small lab trial. Ask your provider if you’re on blood pressure treatment. For the other claims, see the hot tub benefits overview linked above.
Sources
- Cleveland Clinic, “Soak It In: How Hot Tubs Can Boost Your Health,” November 17, 2025: health.clevelandclinic.org
- Brunt VE, et al., “Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans,” Journal of Physiology, 2016 (abstract): pubmed.ncbi.nlm.nih.gov
- Ukai T, et al., “Habitual tub bathing and risks of incident coronary heart disease and stroke,” Heart, 2020 (abstract): pubmed.ncbi.nlm.nih.gov