What are the effects of heat on sleep? 

heat on sleep

The lazy summer days are less conducive to sleep than the winter ones.

Our dream team and partners in sleep data and science, SleepScore Labs, have teamed up with us to explore how summer’s excessive effect of heat on sleep.

During hot summer nights, we’ll also offer tips for sleeping cool and comfortably.

Cooling down methods of the body in hot weather

Heat is released from your body through your skin and through your breathing. Heat is transported through blood vessels. When it’s too hot to sleep outside, these vessels widen, especially those near the skin (or vasodilate), releasing body heat.

Heat exchange with the air is more rapid when shunting vessels are opened. As a result, these vessels lead to redness in your hands, ears, and fingers when you are warm.

overheating while sleeping

What Are the Effects of Hot Weather on Sleep?

Extremely warm evening recommended temperature for sleeping , such as those common during balmy summers, can adversely affect our sleep. For example, sleeping in an environment that is warmer than 87 degrees. Fahrenheit interrupts sleep and reduces important stages of sleep, such as slow-wave sleep and rapid eye movement (REM).

Hot and humid conditions harm sleep quality.

Excessive temperatures at night can negatively impact sleep, it is clear. In places where temperatures are highest year-round, the hottest months can put different demands on sleep quality, so we wanted to study how sleep changes under hot weather in those regions.

An unexpected study performed on Sahelians revealed that, at least in some cases, exposure to extreme temperatures during the day (in the summer, 95-99 degrees Fahrenheit) increases the depth of sleep at night when participants sleep in a cooling environment. 

The extreme daytime heat in these regions may have had a primary, selective impact on slow-wave sleep. In addition, however, sleep disruption, such as nighttime wakefulness and lighter sleep stages (NREM 1).

Despite the striking results, more humid environments may not produce the same results. This is because humidity impairs evaporation and increases the thermal load, making it difficult for us to expel heat.

It isn’t always bad to sleep in the heat.

A small amount of heat can help improve sleep.

Gottlieb explains that “Generally, exposure to extreme heat during the night disrupts sleep, but some studies have shown that mild heating before bed may actually benefit sleep.”

heat on sleep

It is important to keep cool before going to sleep. A review of recent studies showed that taking a warm bath two to three hours before bed significantly improved your chances of falling asleep.

However, more research is needed to determine whether passing through cool water during a shower or passively heating the body during the night can help improve sleep and whether high summer temperatures also contribute to these effects.