Hot days can pose many problems, from strained electrical grids to heat exhaustion and poor sleep. You’re better positioned to avoid or mitigate these uncomfortable and potentially dangerous side effects of high temperatures when you know about hot weather fatigue. But how do high temperatures interfere with sleep? And why do people get heat exhaustion?  Understanding why you get hot and tired from excessive heat or how heat fatigue develops can make managing hot nights easier.

Why Does Heat Make You Tired?

Heat exhaustion and sleep have a complicated relationship. Too much time in the heat can make your body and mind feel tired and dull. Different people have varied comfort ranges and thresholds, but enough heat will have this effect on anyone. But why does heat make you tired? In simplest terms, when you are tired from the heat, it’s because the temperature is forcing your body to work harder to keep you cool. The human body must maintain a core temperature in the upper 90s (Fahrenheit), and deviating from this can have side effects ranging from discomfort to being fatal. For instance, internal body temperatures over 104 F can be fatal.   

The hotter it is around us, or the hotter our body gets from use, the more it must work to maintain a safe core temperature. Water and sweating play a significant role in these cooling mechanisms, which is a substantial part of why staying hydrated when it’s hot is so essential.

Too Much Heat 

Excessive temperatures can do more than make you feel heat and fatigue. Too much exposure to high temperatures can cause numerous problems, including serious health risks. Different people can have different tolerance and risk levels for high heat, and these risks can vary by context. In general, you are more at risk if you are younger than four or older than 65, heavier, unused to high temperatures, on medications that impact the body’s cooling abilities, or in an area with a high heat index. Too much heat can lead to heat exhaustion, or in severe situations, heatstroke.

Heat exhaustion often includes some or all of these symptoms:

  • Sweating
  • Lightheaded
  • Fatigue
  • Headache
  • Dizziness
  • Nausea
  • Fast, weak pulse

If you are experiencing these symptoms or believe you are suffering from heat exhaustion, contact your physician, remove yourself from the heat and direct sun, and drink water.

Recent Heat Waves And The Impact On Your Sleep

With the recent heat waves, many people are experiencing higher temperatures than are good for them. The effects of heat waves can carry into our sleep patterns, causing us to experience “increased wakefulness and decreased rapid eye movement sleep…,” according to the National Institute for Health (NIH). By the 2010s, heatwaves in the U.S. were happening three times as often as they had been in the 1960s. Over this period, the Environmental Protection Agency (EPA) shows that heatwave frequency, duration, seasonal length, and intensity have all been steadily increasing. When considered together, these two sets of findings imply that it might be a good time to learn how to sleep better in heatwaves.

How to Sleep In The Heat

When it comes to hot nights, you can do a few things to make it cooler on yourself. Below are some tips and tricks to help you sleep through the night, even when it’s sweltering out.

Stay hydrated

Water is one of the primary tools your body uses to stay cool. Stay hydrated during the day with plain water and keep a water bottle nearby when you sleep.

Minimize blankets

Heavy blankets can be comfortable at first, but they trap more and more of the body’s heat as the night goes on. Consider using a light sheet instead to help your body cool off easier.

Go for breathable bedding

Some fabrics are better than others for releasing heat and wicking away sweat. In general, cotton is one of the better fabrics for breathability. Still, any fabric which breaths well and wicks moisture can work.

Use a cooler mattress

Mattresses tend to sleep at different temperatures depending on their design and materials. If you sleep hot and are looking for a new mattress, consider some of the best cooling mattresses of 2021.

Don’t overdress

If you wear pajamas at night, consider sets with less fabric and lighter, more breathable materials. Just like heavy blankets, wearing thick pajamas will often trap your body heat, making it harder to cool down and sleep.

Keep a fan and spray bottle nearby

A little bit of water and some moving air can go a long way in helping the body cool down. If you get too hot in the night, you can point the fan at yourself and spray a little water onto yourself. This helps the body shed heat faster, just don’t spray the water towards the fan or any other electronics.

Choose the coldest room for your bedroom

Cold air sinks and heat rises. The lower and more insulated a room is, the easier it will be to keep it cool. This often means that one part of the house stays colder than the rest. This may be a basement, den, or downstairs bedroom.

Eat light dinners and avoid late-night snacks

Digesting food can generate significant heat in the body, and the heavier the food is, the more heat it tends to create.

How the body cools itself

A significant part of how the human body cools itself is through a combination of vasodilation and sweating. Vasodilation involves blood vessels expanding to allow increased blood flow, resulting in more blood flowing through the veins near the skin’s surface, allowing heat to then flow out of the body. Sweating helps the cooling process as sweat droplets absorb heat from the skin and carry it away from the body when the droplets evaporate. Although the outcome is a lower temperature, the cooling process raises the heart rate. This can lead to weariness or fatigue, but it can also interrupt sleep since an elevated heart rate can contribute to wakefulness.

Heatwaves Are Increasing

The last few decades have seen a steady increase in heat waves, as reported by the EPA and the U.S. Global Change Research Program (USGCRP). The data presented highlights an overall increase in the duration, frequency, and intensity of heatwaves. Potential health risks around extreme heat even prompted the Center for Disease Control (CDC) to release a guidebook on the matter in 2016. Perhaps most troublesome of the data reported by the EPA is that the average length of the annual heatwave season, based on their indicators, has grown by 47 days since the 1960s. The more common hot nights are, the more important it is to learn how to stay cool.

Preventing Heat Exhaustion

When it comes to preventing heat fatigue and heat exhaustion, the best advice is to stay hydrated and stay out of the heat. Of course, staying out of the heat isn’t always an option. In those situations, keep water with you, wear sun cover (preferable clothing and hat-wear that can breathe but will also block the sun), avoid direct sunlight as much as possible, and cool off indoors whenever you are able.

Final Thoughts

Few things matter for health and well-being as much as quality sleep. With heat waves coming more often and lasting longer, it’s essential to learn how to mitigate this hot weather’s impact on your sleep. For better sleep, take precautions to avoid heat exhaustion and make your sleeping arrangements better aligned for staying cool. Consider the tips mentioned in this article or some of the best mattresses for staying cool while you sleep.