Sleep Mysteries

Unsolved Sleep Mysteries

Why Does Heat Makes You Sleepy and What Can You Do About It?

Welcome to Unsolved Sleep Mysteries, where we crack the code on the questions keeping you up at night. Get ready to rest easier.

How many times have you yawned non-stop or felt drowsy and lethargic on a warm summer day? You wonder if the sun is zapping your energy, and it kind of is.  Before you reach for another cup of coffee or sugary pick-me-up that can worsen fatigue, read on–if you can stay awake–to find out what’s really going on with your body.

Why you’re hot and tired

When it’s hot outside, your body works overtime to keep you cool, striving for a state of homeostasis (or internal balance) by maintaining a consistent, normal, internal temperature. The process of your body trying to stay cool requires a lot of energy; this is one reason you feel tired in the heat, experts say.

In addition to causing sleepiness, heat affects other biochemical processes in your body, and dehydration may be a culprit.

For example, baking in the sun for extended periods of time can lower your blood pressure, triggering a head rush that can make you feel dizzy. Symptoms may worsen if you’re physically active outdoors during peak hours when the sun is at its hottest. You may sweat heavily, feel lightheaded, nauseated, or have a headache.

Bottom line: Physical exertion, sweating, and staying outside for hours when it’s hot, depletes your body of fluid and salt, leading to dehydration. The end result? You feel fatigued, lethargic, and sleepy.

Stay Cool & Awake In The Heat​

4 Tips To Stay Cool & Awake In The Heat

1. Drink enough water

By the time you feel thirsty, you’re already dehydrated. The goal is to drink plenty of water before you experience thirst. To avoid dehydration, experts recommend drinking at least 16-20 ounces of fluid one to two hours before an outdoor activity. Drink another 12 ounces of fluid for every 10 to 15 minutes spent outside. After the activity, drink at least another 24 ounces of water (this is officially your summer job). The easiest way to tell if you’re properly hydrated is to check the color of your pee: Straw-colored, pale, or clear, means you’re good to go.

2. Seek shade

Your best bet is to stay indoors during the hottest part of the day. If you have to go out, wear a wide-brimmed hat and lightweight breathable fabrics, like cotton, in light colors that don’t absorb heat.

3. Keep your workout indoors

Exercising in extreme heat can make you susceptible to heat stroke. Period. Find an air-conditioned space to crush your fitness goals.

4. Replenish your electrolytes

Sodium is an important electrolyte that helps maintain a normal balance of fluids in your body. You lose sodium in sweat and urine. Instead of downing a commercial sports drink loaded with processed sugar, too much salt, and artificial colors, try coconut water, or make a DIY electrolyte drink with water, lemon juice, a pinch of Celtic sea salt, and raw honey. We’ll take two, please!

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