Soaking in a hot tub can be good for you: research links warm-water bathing before bed to falling asleep faster, buoyancy takes weight off sore joints, and a large Japanese study tied frequent hot baths to lower rates of heart disease and stroke. Most of that research is on baths and much of it is observational, and hot tubs carry real limits for pregnancy, some heart conditions and alcohol.
Here is what the studies show about hot tub health benefits, and how to soak safely.
Can a hot tub help you sleep better?
A warm soak 1 to 2 hours before bed may help you fall asleep faster. A 2019 systematic review in Sleep Medicine Reviews screened 5,322 articles, found 17 that met its criteria and pooled 13 of them (Haghayegh et al., 2019). Warm baths or showers taken 1 to 2 hours before bedtime, even for as little as 10 minutes, were linked to falling asleep faster, and water of 40°C to 42.5°C (104°F to 108.5°F) was linked to better self-rated sleep quality and sleep efficiency.
The authors’ explanation is that warm water draws blood to the hands and feet, which helps the body shed heat and cool down before sleep. They also note the research is limited, especially on the best timing and length of a soak. Hot tubs should stay at or below 104°F (CDC, 2025), the low end of the range in that review.
Does a hot tub help sore muscles and joints?
A hot tub takes weight off your joints while you soak. Bruce Becker’s 2009 review of aquatic therapy in PM&R reports that water up to the hips offloads about 40% of body weight, water to the belly button about 50% and water to the lower chest 60% or more (Becker, 2009). That is why sitting in warm water can feel easier on stiff knees, hips and backs.
Warm water also changes circulation. Becker reports that cardiac output rises by about 1,500 mL per minute with water at collarbone depth, and that the rise depends strongly on temperature, from about 30% at 33°C to 121% at 39°C. That extra blood flow is part of why a soak feels relaxing, and it is also why hot tubs are not right for everyone (see the safety section below).
For therapy goals, such as recovery from an injury or chronic back pain, a warm-water pool with a trained therapist is a different tool from a home hot tub. Our post on how hydrotherapy can help you heal covers aquatic therapy.
Is soaking in a hot tub good for your heart?
Regular hot soaks are linked to lower heart disease and stroke risk, but the evidence is observational. The Japan Public Health Center-based study followed 30,076 adults aged 40 to 59 from 1990 to 2009 (Ukai et al., Heart, 2020). People who took a hot bath almost every day had a 28% lower risk of cardiovascular disease (hazard ratio 0.72) and a 26% lower risk of stroke (hazard ratio 0.74) than people who bathed 0 to 2 times a week.
The authors caution that bathing habits were only measured once, that frequent bathing may reflect better living conditions, and that other unmeasured factors could explain part of the link. The baths in the study were typically 40°C to 42°C, in a culture where daily tub bathing is common. The study does not show that a hot tub prevents heart disease.
Who should be careful in a hot tub?
Most healthy adults can soak safely, but a few groups need extra care:
- Everyone: keep the water at or below 104°F (40°C) and skip alcohol before or during a soak (CDC, 2025). At 104°F, core body temperature rises about 0.1°F for each minute in the water (Becker, 2009), so long soaks add up.
- Young children: CDC says children younger than 5 should not use hot tubs.
- Pregnancy: CDC advises talking to a healthcare provider first. HealthLinkBC’s 2023 guidance says to keep the water below 102°F, limit soaks to 10 minutes, keep your arms and chest above the water and get out right away if you feel dizzy or faint (HealthLinkBC, 2023).
- Heart conditions: Becker’s review lists uncompensated heart failure and a very recent heart attack as reasons to avoid hot tubs. Anyone with a heart condition or high blood pressure should ask their doctor first.
Does hot tub water quality affect your health?
Yes. The health benefits only count if the water is clean. CDC says germs can spread through hot tub water and cause skin, lung and stomach illness, and it recommends free chlorine of at least 3 ppm or bromine of 4 to 8 ppm with a pH of 7.0 to 7.8 (CDC, 2025). Our guide to hot tub chemicals explains chlorine, bromine and safe levels.
Clear Comfort’s hydroxyl-based AOP is a supplemental system for home spas that breaks down contaminants in the water, so a hot tub can run with a low chlorine or bromine residual. The CCW25 treats portable spas, swim spas, plunge pools and personal hot tubs up to 30 GPM. To keep biofilm from building up in the plumbing, see how to get rid of hot tub slime.
Frequently asked questions
Are hot tubs good for you?
For most healthy adults, a hot tub can be good for you. Research links warm-water soaking to falling asleep faster, less load on sore joints and, in one large observational study, lower rates of heart disease and stroke. Keep the water at or below 104°F, skip alcohol and check with a doctor if you are pregnant or have a heart condition.
How long should you stay in a hot tub?
There is no single limit for everyone, so keep soaks short and get out if you feel dizzy, sick or overheated. At 104°F, core body temperature rises about 0.1°F for each minute in the water, according to a 2009 review. During pregnancy, HealthLinkBC advises water below 102°F and no more than 10 minutes.
Is it good to use a hot tub before bed?
It may help. A 2019 review of 17 studies found that warm baths or showers 1 to 2 hours before bedtime were linked to falling asleep faster and better self-rated sleep. Give your body time to cool down before you go to bed.
Can you use a hot tub while pregnant?
Talk to your healthcare provider first, as CDC advises. HealthLinkBC’s guidance for pregnancy is to keep the water below 102°F, limit soaks to 10 minutes, keep your arms and chest out of the water and get out right away if you feel dizzy or faint.
What temperature should a hot tub be?
CDC says hot tub water should not be higher than 104°F (40°C). Lower temperatures are a better choice for long soaks, for children who are old enough to use a hot tub and during pregnancy, when guidance calls for water below 102°F.
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