what does heat do to your body?
think of your body like a car. it needs fuel, it works hard to keep you moving, and in hot weather, it can overheat if you're not careful.
3 minute read
heat affects more than just comfort. it can be detrimental to your heart, mind and even sleep. so, pay careful attention to the time you spend in the sun and remember to stay hydrated!
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think of your body like a car. it needs fuel, it works hard to keep you moving, and in hot weather, it can overheat if you’re not careful.
in the scalding sun of summer, your engine overheats, and activates the cooling system—sweat—which lowers your body temperature as it evaporates. however, in extreme heat or humidity the sweat can’t evaporate quickly enough and your body can’t cool fast enough, producing more sweat in a cycle that continually drains your internal supply of water and electrolytes.
this cycle may be uncomfortable on the outside, but there is also a lot happening inside your body that you need to be aware of. here’s what the heat does to your body—from the inside out.
you lose fluids fast
according to an article by the american college of sports medicine, humans can lose more than a litre of sweat per hour doing any physical activity in hot conditions. that litre—water taken from your body—is depriving your vital organs and internal systems from both coolant and fuel.
intense heat doesn’t just affect your body temperature, but the efficiency of necessary operating systems that allow you to live. replacing fluids regularly doesn’t just cool you down, but is important to avoid dehydration, allowing you to work at full capacity.
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your heart works harder
to help release heat, your blood vessels widen in a process known as vasodilation. these dilated blood vessels transfer heat straight to the skin’s surface, where it can dissipate into the air. this release of heat comes at a cost, however, as wider blood vessels lower your blood pressure, which means your heart must pump faster to keep blood flowing. this puts a lot more strain on your cardiovascular system. in a dehydrated state, especially with pre-existing circulatory issues, this strain can increase your risk of dizziness, heart palpitations, and fainting.
in some cases, your blood vessels can expand to the point of leakage in surrounding tissue, known as heat edema. usually harmless, this effect can actually cause extremities such as hands and feet to swell and become puffy.
you lose important minerals
those electrolytes in your sweat mentioned earlier are pretty important. sodium, potassium, calcium, and magnesium are all the properties that make sweat salty, but they also are essential for muscle contraction, nerve signaling, and fluid balance. losing a large amount of them can be dangerous.
when electrolytes are lost through sweat and aren’t replaced, your body is drained and muscle cramps, fatigue, and even confusion can slow you down to a snail’s pace. water contains smaller amounts of these electrolytes, but those doing intense physical activity under the sun’s glare may consider replenishing themselves with mineral-rich water. athletes need electrolytes!
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it messes with your sleep
every night, your body naturally reduces its temperature to fall asleep. if your bedroom is too hot, that cooling process is disrupted and with it—along with your circadian rhythm, the internal clock that tells you when it’s time to rest.
it’s recommended to keep your room cool—not cold—during hot days to help encourage the circadian rhythm. don’t be afraid when you feel warm at night either! that’s your core re-distributing heat to the surface of your skin, just like vasodilation, which is where you feel the warmth. everything inside is cool for a good night’s rest.
it slows down your brain and can affect with your mood
with less blood being pumped to various organs and rather re-distributed to expel heat, there is a lot less being sent to your brain. along with dehydration, which further impacts cognitive performance, your brain can actually overheat. fatigued, sluggish, distracted brains can only work so hard, and the impaired prefrontal cortex can take the brunt of it, the area responsible for decision-making and focus.
this lack of cognitive clarity can create irrational mood swings as well. with less energy to spend on self-regulation, those exposed to intense heat for long periods can become irritable, stressed, and even aggressive.
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heat can also create anxiety and discomfort. according to a 2023 article in health science reports by researchers mohammad khairul kabir rony and hossain mohammad alamgir, “high temperatures can induce feelings of anxiety and unease. the body’s stress response is activated, leading to heightened levels of stress hormones, such as cortisol and adrenaline.”
heat affects more than just comfort. it can be detrimental to your heart, mind and even sleep. so, pay careful attention to the time you spend in the sun and remember to stay hydrated!
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