Spend a day at the beach swimming, playing volleyball, or participating in any other physical activity, and you’ll no doubt be exhausted by the end. However, spend the entire time lounging in a beach chair and you'll likely find yourself just as sleepy. Why does your body get so tired from simply being in the heat, even if you're doing basically nothing? It’s because your body actually is doing a lot. It’s trying to maintain your internal temperature, and when you’re surrounded by heat, that requires significantly more effort. Sweating, the human body’s most well-known cooling mechanism, is quite labor-intensive, too. Your heart rate and metabolic rate both increase, burning through your energy and potentially leaving you dehydrated. In addition to fluid loss, the loss of essential salts and electrolytes such as potassium, calcium and magnesium can also make you feel worn out. For the most part, tips for avoiding heat-generated fatigue are self-evident: Stick to shady spots if you’re outside, hop in a cold shower if you’re inside, and stay as hydrated as possible. Fruits and vegetables make great snacks, since they’ll help replace lost fluid and minerals; and a loose-fitting, breathable outfit will let your skin release more heat than something constricting. Now that you know how hard your body has to work on a hot day, you can freely indulge in lying around without feeling lazy.
