Why We Feel More Tired in Summer: A Scientific Explanation

Recent studies have highlighted a concerning trend: half of the respondents suffer from worse sleep quality in the summer compared to the average. This issue is exacerbated during the summer months, with global warming playing a significant role. An international study has revealed that global warming results in an average loss of 44 hours of sleep per year. As temperatures rise, this sleep deficit is expected to worsen, making summer nights particularly challenging.

The Science Behind Summer Fatigue

Research indicates that if ambient temperatures continue to increase, we could see a loss of 50 to 58 hours of sleep annually by the end of the century due to higher nighttime temperatures. Scientists at the University of Tokyo have pinpointed that when nighttime temperatures exceed 24.8 degrees Celsius (76°F), the frequency of sleep disturbances rises significantly. These disturbances can lead to various health issues, mirroring the effects of heat stroke. Poor sleep is linked to mood disorders, heart disease, obesity, diabetes, and other serious conditions.

Beyond temperature, genetics, lifestyle, and environmental factors influence sleep quality. In the summer, longer daylight hours and oppressive heat add to the difficulty of falling and staying asleep.

Contrary to popular belief, our sleep needs do not fluctuate with the number of daylight hours. This is why changes between winter and summer time, as well as extended daylight, can be stressful. Maintaining a consistent sleep routine, engaging in moderate physical activity during the day, avoiding heavy meals before bedtime, and ensuring a cool sleeping environment are crucial for good sleep hygiene.

What Are the Ideal Sleeping Conditions in Summer?

For optimal sleep during summer, the bedroom temperature should be between 18 and 20 degrees Celsius (64-68°F). While air conditioners and fans are common solutions, shading and special bedroom accessories can also help maintain a cooler environment.

There are several tools to improve sleep during hot nights:

Breathable Bed Covers: Choosing covers made from breathable materials like satin or cotton can significantly enhance comfort during summer. It's also important that bed linens are washable at a minimum of 60 degrees Celsius.
Summer Quilts: For those who need a quilt or blanket even in the heat, summer quilts made from linen or cotton can dissipate heat and moisture, making them a suitable choice.
Cooling Pillows: The right pillow can greatly impact sleep quality. Pillows with cooling gel help reduce body temperature, providing relief in hot weather.
Breathable Mattresses: A high-quality, well-ventilated mattress is crucial for comfort in the summer.
Cooling Mattress Covers: These covers not only protect the mattress but also have a cooling effect due to their material and design, enhancing overall sleep quality.
Smart Watches: While it's important to limit electronic device usage before bed to avoid blue light exposure, some smart devices can be beneficial. They can monitor sleep cycles, help wake you up at the optimal time, and detect sleep disorders.
Eye Masks: Blocking out morning light with curtains, blinds, or eye masks can help extend sleep by promoting the production of melatonin, the sleep hormone.

By implementing these techniques and using the right tools, you can mitigate the impact of summer heat on your sleep, ensuring more restful nights and better overall health.