Hot shower or bath

A warm bath or shower 1–2 hours before bed, at about 40–42.5 °C (104–108.5 °F), can help you fall asleep faster.

• Evidence: Some
• Low effort
• Free
• Works: tonight

Why it matters

To fall asleep, your core body temperature needs to drop. Your body does this by sending more blood to your skin, especially your hands and feet, where heat escapes.

A warm bath or shower speeds this up. The warm water widens the blood vessels in your hands and feet (distal vasodilation). After you get out, that extra blood flow keeps pushing heat out of your body, and your core temperature falls faster than it would on its own. The meta-analysis authors think the size of that drop is what drives the sleep benefit [1].

The same review pulled together 17 studies, 13 with data that could be combined. Water at 40–42.5 °C (104–108.5 °F) was linked to better self-rated sleep quality and better sleep efficiency. When the bath or shower was 1–2 hours before bed, even 10 minutes of it shortened the time to fall asleep [1].

How to do it

1. Time it 1–2 hours before bed. That is the window in which the studies found faster sleep onset [1].
2. Aim for warm, not scalding. About 40–42.5 °C (104–108.5 °F) [1]. If you don’t have a thermometer, it should feel clearly warm but comfortable to sit in or stand under.
3. Stay in at least 10 minutes [1]. The review covered both baths and showers.
4. Get out slowly. Stand up in stages, especially from a deep bath. Hot water lowers blood pressure, and fainting while getting out or in the tub is a real risk [2].
5. Keep the bathroom warm in winter. Moving between a cold room and hot water causes big swings in blood pressure. One review recommends keeping the bathroom and changing area at 20 °C (68 °F) or above, and a few degrees warmer for older people [2].
6. Then cool down. Go to a cool bedroom in light clothing so the heat can escape. See room temperature.

Safety

• Heart conditions or low blood pressure: hot water drops your blood pressure. In Japan, where long, hot, deep baths are common, an estimated 19,000 people die each year while bathing, mostly older people in winter, often after fainting and drowning [2]. If you have heart disease, low blood pressure, take blood pressure medication, or get dizzy easily, ask your doctor what water temperature and duration are safe for you. Use a shower or a cooler, shorter bath in the meantime.
• Pregnancy: high body temperature in early pregnancy is linked to about twice the risk of neural tube defects in the baby [3]. Don’t use hot baths to raise your body temperature while pregnant. Ask your midwife or doctor about bath temperature.
• Older adults: take extra care getting in and out, and don’t bathe for long in very hot water [2].

Common mistakes

• Showering right before bed and expecting the same effect. The meta-analysis found the benefit when bathing was 1–2 hours before bed [1].
• Making it as hot as possible. The studies used 40–42.5 °C [1]. Hotter water hasn’t been shown to work better, and it lowers blood pressure more [2].
• Going to bed in a warm room under a heavy duvet. The heat has nowhere to go.
• Falling asleep in the bath. Set a timer.

Effect on your sleep score

• Time to fall asleep: shorter when bathing 1–2 hours before bed [1]. We couldn’t access the full paper to check the average size of the effect in minutes.

• Efficiency: better with water at 40–42.5 °C [1].
• Deep sleep, total sleep, wake-ups: the review looked at these too, but the abstract doesn’t report a clear benefit [1].
• HRV and resting heart rate: we found no study measuring them after a pre-bed bath in healthy adults with wearables.

How confident: moderate that it helps you fall asleep; low on how much.

Evidence

Rated Some. The 2019 systematic review and meta-analysis is the main source [1]. Its authors note that there aren’t many studies, and that the best timing, duration and exact mechanism still need more research. The clearest results were for self-rated sleep quality, sleep efficiency and time to fall asleep [1]. A review of Japanese bathing habits also reports that baths improve sleep, particularly time to fall asleep in winter, while describing the safety risks for older people [2].

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.