the importance of sleep for mental health lack of sleep effects on brain how to sleep better in hot weather tips for sleeping in hot weather how to improve sleep quality

How to improve sleep quality in summer: tips for sleeping in hot weather.

Published at Jun 1, 2023 | Updated at Feb 8, 2024

Sleep is essential for survival. Getting good quality sleep regularly is needed for healthy functioning. Your brain is actively working while you sleep- performing a deep clean, and making you smarter, stress-free, and happier. Your body has an internal timetable that determines when you sleep and wake up. And this timetable is sensitive to outside influences like light and temperature. Understanding how you can modulate these factors in your favour can help you optimise your sleep.

How does the environment impact sleep?

Do you notice changes in your sleep patterns in summer vs in winter? It is the shifts in light and temperature that play a part. Changes in these can contribute to lack of sleep. Effects on brain health as a consequence include increase in stress, low mood and cognition issues [3]. Getting good quality sleep can do wonders for brain health. Read more about how sleep benefits brain health here.

The body clock has evolved to align with day and night changes, based on the availability of light. The main brain chemical that is responsible for putting you to sleep is melatonin and is produced at night. Melatonin is produced from your happy brain chemical, serotonin. Your eye cells are sensitive to light, and with the onset of night, they signal brain cells to convert serotonin to melatonin for sleep [2]. Adequate levels of serotonin are essential to produce sufficient melatonin. One way to ensure a sufficient serotonin supply is to consume its direct building block, 5-HTP that is available in supplemental form. The world’s smallest dense tablet of 100mg 5-HTP can naturally and safely increase serotonin levels. Read more here.

Exposure to light decreases melatonin production. One reason why you may have sleep issues in summer is due to longer periods of daylight, which may hinder adequate melatonin production.

Ambient temperature can also impact your sleep by affecting your body temperature. Your body likes to keep cool when sleeping. Your body temperature drops to induce sleep [4] and this is another factor that can influence your sleep quality. Data collected from over 3.75 million nights’ sleep found that bedroom temperature above 21°C is associated with shorter sleep duration and longer time taken to fall asleep [5] The optimal temperature is between 18-21°C [5]. Almost 50% of seasonal sleep changes were due to temperature changes in summer vs winter [6]. This is another reason why you might have trouble sleeping in summer when temperatures are higher.

Seasons and sleep: what is new?

With global warming, temperatures are gradually on the rise and this could be permanent. A 2022 study looked at 7 million sleep records from 68 countries. They found that with the current rise of temperature, by the year 2099, people are at a risk of losing 50-58 hours of sleep per year [1]. This is an average of 18 minutes sleep loss per night. Women and older adults are at higher risk, and those in warmer countries are anticipated to lose more sleep. Though 18 minutes might seem like a short time, the importance of sleep for mental health should be prioritised, since other factors can also affect your sleep, leading to further loss. Those who slept 6 hours or less had over 35% more risk of getting dementia, had lower brain volumes and lower cognition scores [7] [8]. The good news is building a better sleep is easily achievable and can fix the damage caused by disrupted sleep.

How to sleep better in hot weather? A smooth sailing to dreamland.

Controlling rising global temperature may be out of reach for you, but you are completely in control of your personal environment. Making small improvements can do wonders for your sleep.

Help your melatonin work for you by promoting a dark, sleep-inducing, cool bedroom. The Sleep Foundation recommends 5 tips to manage the light and temperature of your surroundings [9] [10]:

Using blackout curtains to block light to ensure that even during long days of summer you can get adequate hours of sleep.
Use dim lights in bedroom and keep screens like TV and computers away. This will further help in the tuning away distractions.
Keep the bedroom thermostat between 18-21°C to promote the optimal sleep temperature. Use of fans, coolers and window ventilation can help lower the room temperature.
Wear comfortable pyjamas and invest in good quality bedding that helps to keep you cool during sleep.
Taking a warm bath can help promote cooling down before bed.

Light and temperature can have a big effect on how much and how well you sleep. Small changes in your bedroom can bring a major difference in your sleep quality, even when the days get longer and the earth gets hotter.

References

Minor, K., Bjerre-Nielsen, A., Jonasdottir, S.S., Lehmann, S. and Obradovich, N. (2022). Rising temperatures erode human sleep globally. One Earth, 5(5), pp.534–549.

Tähkämö, L., et al. (2019). Systematic review of light exposure impact on human circadian rhythm. Chronobiology international, [online] 36(2), pp.151–170.
Medic, G., Wille, M., & Hemels, M. E. (2017). Short- and long-term health consequences of sleep disruption. Nature and science of sleep, 9, 151–161.
Okamoto-Mizuno, K., & Mizuno, K. (2012). Effects of thermal environment on sleep and circadian rhythm. Journal of physiological anthropology.
Raj, A., Ruder, M., Rus, H.M., Gahan, L., O’Mullane, B., Danoff-Burg, S. and Raymann, R. (2020). 1214 Higher Bedroom Temperature Associated With Poorer Sleep: Data From Over 3.75 Million Nights. Sleep.
Mattingly, S.M., Grover, T., Martinez, G.J., Aledavood, T., Robles-Granda, P., Nies, K., Striegel, A. and Mark, G. (2021). The effects of seasons and weather on sleep patterns measured through longitudinal multimodal sensing. npj Digital Medicine, 4(1).
Chen, J.-C. et al. (2015). Sleep duration, cognitive decline, and dementia risk in older women. Alzheimer’s & Dementia, 12(1), pp.21–33.
Chen, J.-C. et al. (2015). Sleep duration, cognitive decline, and dementia risk in older women. Alzheimer’s & Dementia, 12(1), pp.21–33.
Suni, E. (2020). Light & Sleep: Effects on Sleep Quality. [online] Sleep Foundation.
Pacheco, D. (2020). The Best Temperature For Sleep: Advice & Tips. [online] Sleep Foundation.