heat warning: what does extreme heat do to your body?

it’s starting to get hot. like, really hot. and as we get deeper into summer, the days will only get warmer and dryer  — so yes, install that ac now . but it also may make you wonder: what is all this heat doing to our bodies?

it’s all easier to understand when you consider the human body’s internal temperature, which sits at around 37 degrees celsius. variations within a degree can happen throughout a normal day, but more than that typically occurs during illness or certain environmental conditions — like extreme heat. so as our environment gets hotter, our body does too. as the canadian centre for occupational health and safety (ccohs) describes it, “the body’s internal ‘thermostat’ maintains a constant inner body temperature by pumping more blood to the skin and by increasing sweat production. in this way, the body increases the rate of heat loss to balance the heat burden. in a very hot environment, the rate of ‘heat gain’ is more than the rate of ‘heat loss’ and the body temperature begins to rise.” and that’s where illness steps in.

what are the signs of heat exhaustion?

we’re sweating, we’re tired, and some might even be experiencing dizziness, headache, nausea, goose bumps or muscle cramps. these are all signs of heat exhaustion, which is common in hot temperatures combined with a killer high humidity. people who are especially vulnerable include young children, those over the age of 65, those on medications that may impact their hydration levels (e.g. allergy medicine, beta blockers, tranquilizers), those with chronic illnesses, and anyone who might not be used to being in a hotter climate.

if left untreated, heat exhaustion can lead to heatstroke, which is life-threatening, and happens when your internal temperature hits 41 degrees celsius or higher. this is when our nerve cells — which are the most vulnerable to heat — get extra sensitive . the brain is made up mostly of nerve cells, which is why heatstroke can lead to brain damage, lung issues, heart failure, and kidney or liver injury if left untreated for too long. if your body temperature gets very high — like 48 degrees high — the cells in your body can be destroyed through direct heat damage. the blood flow to our skin is also rising (thus the reddening of your body), putting a strain on our heart, which begins to pump faster. the strain on the heart can cause arrhythmia or cardiac arrest. and as we continue to sweat, our body dehydrates. so, yes, that whole “drink water!” rule during the summer is absolutely the hill to die on.

but when it gets increasingly humid, it’s more difficult for sweat to evaporate from our skin, and that’s a problem because the evaporation process is what actually cools our bodies, according to the ccohs . this is when our ability to produce sweat can actually shut down and our bodies get even hotter, elevating heat exhaustion to heatstroke. that’s when the point of unconsciousness can hit, and you might even experience hallucinations or seizures.

here’s how mike mcgeehin, director of the cdc’s environmental hazards and health effects program, illustrated it to scientific american back in 2010: “the analogy we use is if you’re driving a car and you notice that the temperature light comes on, what’s happening is the cooling system of the car is becoming overwhelmed. if you turn off the car and let it cool, eventually you can start driving again. but if you continue to drive the car, the problem goes beyond the cooling system to affect the engine, and eventually the car will stop.”

treating heat exhaustion?

you can easily treat heat exhaustion — before it leads to heatstroke — by not only keeping the above analogy in mind, but by finding a cooler environment, taking a cold shower, wearing lighter clothing, hydrating (electrolytes are good, too) even when you don’t feel thirsty, and resting. it’s also crucial to avoid strenuous activity in hotter weather, but if you’re an exercise nut, schedule it for cooler parts of the day (early morning, late evening) while taking regular breaks, wear sunblock and um, oh yeah, do not leave your children — or pets — in a parked car. most of us will feel better in an hour or two after following these basic prevention tips. but what if you’re not? or if you’ve experienced a seizure or delirium? time to head to the emergency room.