Climate change and sleep: are warmer nights making us sleep worse?

When we think about climate change, we imagine increasingly hot summers, periods of drought, or extreme weather events. But there is another effect that can reach directly into our bedrooms: the difficulty of sleeping well when nighttime temperatures remain high.

Heat does not only affect our comfort; it can also influence the duration and quality of our sleep.

Why do we need to “cool down” to sleep well?

Our bodies follow a natural rhythm over the course of 24 hours. As bedtime approaches, our core body temperature gradually begins to decrease: this is one of the physiological processes that accompanies the body’s preparation for sleep.

For this reason, maintaining an ideal sleeping temperature can help create more favorable conditions for restful sleep.

To release heat, the body increases blood flow to the skin, particularly to the extremities. However, when the temperature of the room and the surrounding environment remains very high, this process can become more difficult.

The result? Our sleep may become more disturbed, with more frequent awakenings and a reduced feeling of recovery in the morning.

Does more heat really mean less sleep?

Apparently, yes.

One of the largest studies on the subject analyzed the sleep patterns of 47,000 people across 68 countries and compared them with local weather data.

Researchers observed that higher nighttime temperatures tend to delay the onset of sleep, thereby reducing its overall duration.

In other words, when nights become very hot, our bodies have greater difficulty maintaining their normal sleep habits. It is therefore not surprising that the connection between heat and insomnia becomes particularly noticeable during the hottest periods of the year.

The same study also developed projections for the future: by the end of the century, suboptimal temperatures could be associated with an average loss of approximately 50–58 hours of sleep per person every year.

Climate change: nights are part of the problem too

During a heatwave, it is not only the temperature reached during the hottest hours of the day that matters. What happens after sunset is equally important for our bodies.

Normally, nighttime allows people, buildings, and the surrounding environment to release some of the heat accumulated during the day. When temperatures remain high throughout the night, however, this recovery becomes more difficult.

In cities, the phenomenon can be further intensified by the urban heat island effect: buildings, asphalt, and other surfaces retain the heat accumulated during the day and slowly release it over the following hours, contributing to higher nighttime temperatures.

This is why a succession of very warm nights can result not only in a few hours of lost sleep, but also in accumulated tiredness, difficulty concentrating, and a general feeling of reduced recovery.

Who is most affected by hot nights?

Heat does not appear to affect everyone in the same way.

Research has found more pronounced effects among older people, women, and those living in regions that already experience high temperatures.

The characteristics of the home can also make a difference: exposure to sunlight, ventilation, thermal insulation, and the ability to cool indoor spaces all contribute to determining the microclimate of the bedroom.

For this reason, in a future characterized by hotter summers, creating an environment that supports restful sleep could become an increasingly important part of our daily sleep hygiene.

How can we protect our “Healthy Sleep” from the heat?

We cannot control the outdoor temperature, but we can take action on the small environment that surrounds us while we sleep.

A few simple measures can help make the bedroom more comfortable during warmer nights:

• limit direct sunlight during the day by using curtains, shutters, or blinds;
• ventilate the room when the outdoor temperature drops;
• choose lightweight bed linen and textiles suitable for the season;
• avoid unnecessarily leaving electronic devices and other heat sources switched on;
• keep sleep and wake times as regular as possible;
• pay attention to the entire sleep system, as the mattress, pillow, covers, and bed linen all contribute to the comfort we perceive during the night.

In particular, choosing breathable mattresses and materials designed to promote good air circulation can help limit the build-up of heat and moisture while we sleep.

The characteristics of the foams used in the sleep system can also affect the perception of coolness. For example, Memory Fresh Blue: thanks to its special composition and advanced nanotechnology (PCM), it can absorb excess heat and gradually release it as the temperature drops, helping to maintain the ideal temperature for falling asleep for several hours.

A comfortable environment is an ally for better sleep

Climate change reminds us that nighttime well-being does not depend solely on how many hours we spend in bed.

Temperature, ventilation, humidity, and the characteristics of the environment in which we sleep all contribute to the level of comfort needed for a good night’s rest.

If nights become warmer, it therefore becomes even more important to design the bedroom as a space truly dedicated to recovery, paying attention to its microclimate and choosing solutions suited to different seasons.

Because taking care of the environment in which we sleep means, night after night, taking care of our Healthy Sleep too.