When you go out on a hot day, you get weary quickly. But why is it that hot heat makes you sleepy? The reason for this sluggishness is straightforward. According to Dr. Michelle Casey, regional medical director for Duke Health in North Carolina (Geggel, LiveScience, 2017), the body works hard to keep itself cool, and this extra exertion makes you fatigued. Our bodies work extra hard to maintain our body temperature during hot summers or when we spend a lot of time outside. Maintaining a stable body temperature requires a lot of energy, especially on exceptionally hot days (Kozak, 2020).
Reason
When you go out on a hot day, you immediately feel tired. But why does hot weather make you sleepy? The explanation for this lethargy is simple. The body works hard to keep itself cool, and this extra work makes you feel tired, said Dr. Michelle Casey, regional medical director for Duke Health in North Carolina (Geggel, LiveScience, 2017). During hot summers or when we spend a lot of time outdoors, our bodies work excessively hard to regulate our body temperature. It takes a lot of energy to maintain a constant body temperature, and even more so on extremely hot days (Kozak, 2020).
Example
Per Smiley (2022), temperature is an equally powerful trigger of sleep composition and depth as light. For you to get to sleep and remain asleep, you need to lower your core temperature by about 1 degree Celsius, or about 2 degrees Fahrenheit. That’s why it’s easier to fall asleep in a room that’s too cold than in one that’s too hot, because a room that’s too cool will at least steer you in the right temperature direction for a good night’s sleep.
Processes
Above all, vasodilation is necessary to maintain an average body temperature of 98 degrees. Vasodilation is the process by which the blood dilates, allowing more blood to flow near the surface of the skin and releasing heat. This allows the body to cool down, but at the same time may make the person appear “red in the face.” This consumes energy and can tire a person out. Sweating is another way to keep our bodies cool. When we sweat, our skin is cooled as the sweat evaporates. Inside the body, though, sweating increases the heart rate and metabolic rate and consumes large amounts of energy. Sweating excessively can also make you extremely tired and sleepy (Kozak, 2020).
How to prevent feeling hot
- Drink plenty of water.
To prevent dehydration and sleep deprivation, drink plenty of water. Even if you do not feel thirsty, you must restore lost fluids if you are sweating. However, not all fluids are helpful, and Hackensack Meridian Health advises avoiding caffeinated beverages and alcohol.
- Put on sunblock.
Wear sunscreen to protect your skin from further sun damage and dehydration. The majority of specialists recommend at least SPF 30. Sunglasses and hats can also help prevent sunburn (Zwarensteyn, 2021).
References
Geggel,LiveScience, L. (2017). Why Does Being in the Heat Make Us Feel Tired? [online] Scientific American. Available at: https://www.scientificamerican.com/article/why-does-being-in-the-heat-make-us-feel-tired/ [Accessed 1 January 2023]
Kozak, A. (2020). Why Do Hot Temperatures Make You Feel Tired? [online] spectrumnews1.com. Available at: https://spectrumnews1.com/oh/columbus/weather/2020/08/13/why-do-hot-temperatures-make-you-tired [Accessed 8 January 2023]
Smiley, J.D. (2022). Why heat makes you feel tired and sleepy, according to science. [online] www.medicalnewstoday.com. Available at: https://www.medicalnewstoday.com/articles/why-heat-makes-us-sleepy-tired [Accessed 8 January 2023]
Zwarensteyn, J. (2021). Why Heat Makes you Sleepy. [online] Sleep Advisor. Available at: https://www.sleepadvisor.org/why-heat-makes-you-sleepy/ [Accessed 8 January 2023]
