Why Does The Heat Always Me Make Feel Sleepy?

why does heat make you tired

Who doesn’t love to spend time at the beach and get a nice tan? I know I do!

Despite the fun times outdoors under the sun, most people forget there are after-effects of spending too much time in the heat. One of the most common side effects is sleepiness; it’s not uncommon to nap after a long day out in the scorching hot sun.

Several scientific reasons explain why heats make you feel so tired. Many people often consider this feeling of exhaustion a coincidence while others assume they have overdosed on vitamin D. But these are only myths. We break down the most common reasons why the heat will make you feel sleepy.


Even if you do not engage in any physical activity while out in the hot sun, you are still susceptible to dehydration if you’re not careful. The main reason behind this is that your body is sweating to maintain a balanced body temperature.

As you sweat, you lose salts and fluids which is what causes dehydration. One of the main symptoms of dehydration is fatigue. If you feel that the heat makes you tired, you should immediately get a bottle of water or a water-based drink. Even if you don’t feel worn out, drink water frequently so you can avoid further dehydration.

Chemical Changes in Body

It is common knowledge that ultraviolet rays from the sun can easily penetrate your skin and cause damage to it. Exposure to UV rays can cause skin pigmentation, wrinkles, and sunburn. This is why you should always wear sunblock when going outside for prolonged sessions.

The chemical changes that result in skin related problems can also be one of the reasons why you are fatigued after spending time out in the heat. Thus, if possible, avoid going outside during the hottest hours and stock up on those salty snacks to substitute for the salts you will lose from sweat.

salted snacks

Regulation of Body Temperature

When your body is exposed to the sun, it needs to work more to maintain the optimum body temperature. If the temperature outside is hotter and you have a bulkier frame your body will need to work even harder. The human body is designed in such a way that it cools down naturally by using energy and producing sweat.

Sweat is produced by the body to cool down using the vaporization process. For this method, our body burns extra fats to produce energy. In hot temperatures, the metabolic system and heart rate also increase to help your body work harder. So, if you’re wondering why heat makes you sleepy, tired and exhausted, this is part of it!

Low Blood Pressure

If you stay outside for a long time, chances are your blood pressure will go down. When that happens, most people start to feel sleepy. However, some folks get extreme headaches and feel dizzy. If you feel dizzy, go to a doctor or a paramedic immediately.

Most of the time, a slightly lower blood pressure means that less blood is being sent to your brain. Therefore, less oxygen to your brain equals a more exhausted you.

woman having a headache

3 Tips for Heat Exposure

Here are some handy tips for you to follow when you go out in the blistering heat.

Dress Correctly

You should go with light colored clothes that have a loose fitting. Dark colored clothes absorb more heat, and tight clothes may cause a restriction in the evaporation of sweat.

Always wear your sunglasses when it’s sunny outside. If you intend to stay out longer, wear a hat; it will protect you from UV rays. Never forget to use sunscreen, even if it is cloudy.

Stay Hydrated

When you’re experiencing hot weather, you tend to sweat and lose fluids from your body. Always bring water with you and do not wait until you feel thirsty to drink it. In fact, drink water frequently to prevent dehydration. You can also drink fresh juice to remain hydrated and to get all the important nutrients.

Do Not Go in Sun in Peak Hours

Do not go outside in the sun during peak hours from 10 a.m. to 2 p.m., provided you can avoid it. During this time, the sun rays are the strongest and fall at an angle that the ultraviolet rays can be the most dangerous. Therefore, it is best to avoid this time slot.


Everyone loves to spend time outside in the summer, however, it can make you feel dizzy and worn-out because of dehydration, low blood pressure, and other reasons discussed above.

That said, there are many ways to ensure that you do not get tired or burn out under the sun. The most important one of them is to keep your water intake good and wear light, airy clothes. Both of these tips will help you keep cool and retain your body salts.

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