Sauna

Many regular sauna users say it helps them sleep, but no good trial has tested it. If you enjoy it, finish an hour or two before bed, drink water and skip the alcohol.

• Evidence: Weak
• Medium effort
• Medium cost
• Works: tonight

Why it matters

The idea comes from what heat does to your body temperature. Your core temperature needs to fall for you to fall asleep. A hot bath or shower in the evening warms you up, then makes your hands and feet send heat out, and your core cools faster afterwards. A meta-analysis found that a 40–42.5 °C (104–108.5 °F) bath or shower 1–2 hours before bed, for as little as 10 minutes, shortened the time it took to fall asleep [5]. A sauna heats you in a similar way, so it may work the same way. But that’s a guess: the bath studies didn’t test saunas.

Most of the support for sauna and sleep is people’s own reports. In a global online survey of 482 regular sauna users, 83.5% said sauna helped their sleep [2]. In a Swedish survey of 588 regular users, women reported better sleep after sauna but men did not [3].

A sauna is also very hot. A traditional Finnish sauna usually runs at 80–100 °C (176–212 °F), with sessions of 5–20 minutes. Infrared cabins run cooler, at about 45–60 °C (113–140 °F) [1]. That’s a real strain on your heart and blood vessels, which is why the safety notes below matter.

How to do it

1. Check the safety notes first (in Common mistakes) if you have a heart condition, low blood pressure, or are pregnant.
2. Finish 1–2 hours before bed. This copies the timing that worked for hot baths [5]. Going straight from a hot sauna into bed may leave you too warm to fall asleep. We found no study that tested sauna timing.
3. Keep sessions short. Stay within the 5–20 minute range used in Finnish sauna studies [1], and get out sooner if you feel dizzy or unwell.
4. Drink water before and after. You lose fluid by sweating. Dizziness, dehydration and headache were the most common problems sauna users reported [2].
5. Keep your bedroom cool so the cooling-off phase can carry on in bed. See room temperature.

If you don’t have a sauna, a hot shower or bath has better evidence for sleep and costs far less.

Common mistakes

• Drinking alcohol in or before the sauna. Alcohol during sauna raises the risk of low blood pressure, heart rhythm problems and sudden death [6]. In Finland and Sweden, half or more of sauna deaths involved alcohol [1]. Alcohol also harms sleep on its own; see alcohol.
• Ignoring heart conditions. Unstable angina, a recent heart attack and severe aortic stenosis are reasons not to use a sauna. Many people with stable heart disease can use one safely [6], but ask your doctor first.
• Ignoring low blood pressure or dizziness. Dizziness is one of the most common complaints [2]. If you have low blood pressure, take blood pressure medicine, or get light-headed when you stand up, ask your doctor before using a sauna, and stand up slowly when you leave.
• Assuming it’s fine in pregnancy. A review of 12 studies found that sitting in a 70 °C (158 °F) dry sauna for up to 20 minutes did not raise pregnant women’s core temperature to the level linked to harm for the baby [7]. Even so, pregnant women are generally advised to avoid heat stress [7], and hotter or longer sessions weren’t tested. If you’re pregnant, check with your midwife or doctor first.

Effect on your sleep score

• Time to fall asleep and deep sleep: possibly better, if sauna works like a hot bath [5]. We found no study measuring this with saunas in healthy adults.
• HRV and resting heart rate: in a crossover trial, 16 male basketball players used a 43 °C (109 °F) infrared sauna for 20 minutes after strength training. During the session their heart rate was higher and HRV lower than when they rested quietly instead. But overnight heart rate and HRV were no different from a night without sauna, and neither were their self-rated sleep length or quality [4].

How confident: low. Expect a small effect, if any.

Evidence

Rated Weak. A 2018 systematic review found 40 studies of regular dry sauna use, with 3,855 people in total. Only 13 were randomized trials, and most had fewer than 40 people. None was a proper sleep trial [1]. The sleep claims come from surveys of regular sauna users, which can’t separate the sauna from relaxing, time off, or simply liking it [2][3]. The only randomized trial we found that measured sleep was small, all male, and tested sauna after exercise. It found no effect on sleep [4]. The idea that sauna helps you fall asleep by cooling you afterwards rests on hot-bath studies, not sauna studies [5].

General information for healthy adults, not medical advice. If you have a sleep problem that lasts, read when to see a doctor. Sources checked 4 October 2026. Spot a mistake? Tell us.