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How to Sleep Well in High Temperatures: Tips to Beat the Heat for a Restful Night's Sleep

How to Sleep Well in High Temperatures: Tips to Beat the Heat for a Restful Night's Sleep

Published: 29 May, 2024 | 7'

The sun shines, temperatures rise, and nights get longer. Summer, despite its charm, can become a nightmare for those struggling with insomnia due to the heat.

With the help of Dr. Maria Jose Martinez Madrid, a renowned expert in Chronobiology and director of the Chronobiology Working Group of the Spanish Sleep Society, we delve into what happens in our bodies when high temperatures prevent us from sleeping, and we provide some recommendations to avoid it.

Why do we sleep worse in summer: a scientific perspective?

For many, the summer season brings dreaded nights of insomnia and/or less restful sleep. What is the reason for this phenomenon? Science offers us an explanation from the perspective of chronobiology, the discipline that studies the biological rhythms of the human body, to understand how heat affects our sleep and offers strategies to combat it.

Through chronobiology, we can:

  • Understand how heat disrupts our internal clock and affects the mechanism that regulates the sleep-wake cycle.
  • Identify the most effective strategies to combat insomnia in the summer.
  • Create a favorable environment for rest in hot climates.
  • Maximize energy levels during the day despite the heat.

Interview with Dr. Maria Jose Martinez Madrid

1. What is chronobiology?

Chronobiology is the science that studies biological rhythms, which are the rhythmic fluctuations that certain physiological processes in our bodies undergo, and their relationship with time, focusing primarily on circadian rhythms. These rhythms repeat with a period of approximately 24 hours, such as sleep, body temperature, and the release of certain hormones like cortisol or melatonin. We can also find shorter rhythms within biological rhythms, such as heart rate, and longer ones like the menstrual cycle in women.

2. How do circadian rhythms influence our sleep?

As I mentioned earlier, sleep is one of the most evident circadian rhythms in our day-to-day lives. But there are also other circadian rhythms that can regulate the times when we feel sleepy and when we are more alert. For example, the rhythm of melatonin production can induce sleep when it increases in darkness or activate us when it disappears during the day.

When circadian rhythms are desynchronized, as happens with time zone changes or sleep disorders, there can be difficulties in falling asleep or maintaining sleep.

3. What happens on summer nights, and how does the heat affect our sleep?

What happens is that during the night, our internal temperature needs to decrease in order for us to fall asleep. In order for this to happen, we need to expel heat through our skin. If it's too hot outside, we won't be able to cool down, and therefore, we won't be able to fall asleep.

The body, in its attempt to reach the appropriate body temperature for rest, sends signals to the brain that inhibit the secretion of melatonin. Additionally, heat increases heart rate and breathing, making relaxation and deep sleep more difficult.

In summary, heat causes:

  • Difficulty falling asleep: because the body strives to reach a suitable body temperature for rest.
  • Fragmented sleep: frequent nocturnal awakenings due to the discomfort caused by the heat.
  • Less deep sleep: sleep quality is affected, resulting in fatigue and daytime sleepiness.

4. What can we do to combat insomnia in the summer from a chronobiological perspective?

Sleep and Heat

From a chronobiological perspective, some strategies to improve sleep quality in the summer are:

  • Stay adequately hydrated during the day: drinking enough water helps regulate body temperature and prevents dehydration, which can worsen sleep problems.
  • Expose yourself to natural light during the day: since natural light helps regulate the internal clock and facilitates falling asleep at night.
  • Avoid heavy meals and alcohol before bedtime: heavy meals provide a lot of calories, and our bodies have to work hard to digest them.
  • Regulate room temperature: maintaining a cool room, ideally between 18 and 22 degrees Celsius, is crucial for facilitating sleep.
  • Create a relaxing environment in the bedroom: we can use aromatherapy, relaxing music, or deep breathing techniques to help promote sleep.
  • Avoid using electronic screens before bedtime: as the blue light emitted by these devices suppresses the production of melatonin.
  • Avoid intense exercise just before bedtime.
  • Maintain regular sleep, meal, and exercise schedules.

5. During the day, when it's very hot, it's also common to feel low on energy. What can we do to have energy during the day despite the heat?

Some recommendations for putting an end to fatigue during the day in the summer are:

  • Monitor your diet and ensure it is healthy: rich in fruits, vegetables, and proteins that provide us with the necessary energy to stay active during the day.
  • Plan activities according to our circadian rhythms: identify the hours when we feel most energetic and take advantage of them to perform more demanding tasks.
  • Engage in physical exercise: physical activity helps regulate the circadian rhythm and improves mood. However, it's important to avoid exercising too close to bedtime and during the hottest hours, generally between 10:00 a.m. and 4:00 p.m.
  • Take short breaks during the day: even if we feel low on energy, it's advisable to get up and move around regularly, as that helps prevent fatigue.
  • For some people, taking short naps can be useful if necessary, but they should always be under 40 minutes and not later than 5:00 p.m. to avoid disrupting nighttime sleep.

6. What would be the best times to exercise in the summer?

The best times to exercise in the summer would be early in the morning, before the heat reaches its peak, or in the late afternoon, when temperatures start to drop.

The choice of the optimal time to exercise can also be related to a person's chronotype or circadian typology, which refers to their genetic predisposition to be more active and alert at certain times of the day. For example, people with a "morning" chronotype tend to be more active and alert in the morning, while those with an "evening" chronotype tend to reach their peak performance in the afternoon or evening.

Therefore, making use of the times when the body is naturally more alert and energized according to individual chronotype can help optimize performance and minimize the risk of fatigue during exercise.

In addition, exercising early in the morning can help establish a regular sleep pattern and improve overall sleep quality, as exercise can contribute to the regulation of circadian rhythms.

7. Are there any natural supplements and remedies that you usually recommend?

Yes, there are. Melatonin, known as the sleep hormone, plays a crucial role in regulating the sleep-wake cycle. Its natural production increases at night, preparing the body for rest, and decreases in the morning, promoting wakefulness. What happens in summer is that the natural production of melatonin can be affected by various factors, such as prolonged exposure to sunlight or high temperatures. This can make it difficult to fall asleep and can cause nocturnal awakenings, resulting in fragmented and less restful sleep.

In this situation, supplementing with melatonin can be a useful tool. It is usually available in the form of tablets or drops, and its main action consists of mimicking the effects of natural melatonin. However, I always recommend consulting a doctor or sleep specialist before starting melatonin supplementation, as it's important to consider the amount and time of day it should be taken. It should always be taken at the same time to avoid disrupting our body's rhythm, among other recommendations.

It is important to remember that melatonin is not a magical solution, and to achieve restful sleep in the summer, it is essential to combine its use with other strategies. In addition to good sleep habits, which are crucial for proper rest, we can also use valerian to promote relaxation and sleep and consume moderate amounts of caffeine to increase alertness during the day.

8. Regarding sleep monitoring devices and applications. How do they work, and in what cases are they recommended?

Sleep monitoring devices and applications typically use accelerometers and motion sensors to record sleep patterns, such as duration and quality.

They are recommended for people who want to have a better understanding of their sleep and can be useful for identifying problems such as insomnia or sleep apnea. For example, at Kronohealth, we have Kronowise, a device that continuously records an individual's skin temperature rhythms, activity, body position, and light exposure for more than 14 days.

And for people who are essentially bedridden (in hospital wards, nursing homes, neonates...), we have Kronobed, a multisensor system for monitoring and recording environmental and physiological variables at home, on an outpatient basis, or in a hospital setting, which includes various functionalities, including assessing sleep quality and depth.

Final Recommendations from Dr. Maria Jose Martinez Madrid

In conclusion, sleeping well in the summer is essential for maintaining physical and mental health. By implementing the strategies mentioned, such as establishing regular sleep habits and creating a cool and conducive sleep environment, we can enjoy restful sleep during the warmest season of the year.

Furthermore, understanding chronobiology allows us to better adapt to seasonal changes and optimize our performance and well-being throughout the year.


  • Prioritize sleep: dedicate at least 7-9 hours of quality sleep each night.
  • Listen to your body: pay attention to signs of tiredness and go to bed when you feel sleepy.
  • Create a sleep-friendly environment: ensure your bedroom is dark, cool, and quiet.

If you want to learn more about summer health....

María José Martínez MadridAbout the Specialist

Dr. Maria Jose Martinez Madrid @dra_mjmmadrid

Dr. Martinez Madrid holds a degree in Biology from the University of Murcia. She has a Master's in "Technology and Research in Biomedical Sciences," where she began her training in the field of Circadian Rhythms with Dr. Juan Antonio Madrid at the Chronobiology Laboratory of the University of Murcia. She completed her doctoral thesis in the same laboratory, focusing on the effects of chronodisruption caused by shift work. She is currently the founder and director of Kronohealth and a professor in the MASTER'S DEGREE IN SLEEP DISORDERS at the University Institute of Regenerative Medicine and Implantology (UIRMI) since 2020. She is currently the Coordinator of the Chronobiology Working Group of the Spanish Sleep Society.

Health Specialists