How Your Body Adapts to Changing Temperatures

—Getty Images The first heat wave of summer hits like a wall .

One day the air is crisp and cool, and the next it’s impossible to go out without sweating through a shirt.

The store feels like it’s on the far side of the Amazon, or maybe the Gobi.

And yet, the thermometer reveals a number that is not all that high, compared to later in the season.

So why is the heat so unbearable ? Scientists who study temperature regulation have found that the body takes time to adjust to seasonal changes and other thermal changes: a process called heat acclimatization.

Research suggests that in people who regularly spend time outside, the body adjusts how it sheds heat to make the environment less stressful .

“We can adapt to the heat we're in, and it's obviously progressive,” says Julien Périard, a professor at University of Canberra in Australia who studies the phenomenon.

Your body in the summer, it turns out, might be fundamentally different from your body in the winter.

How does the body adapt to seasonal temperature changes? Spending most of your time indoors in the air conditioning might slow the body’s changes, come summer.

“But if we spend time outside exercising, or even just being physically active outdoors, we'll adapt to those conditions,” Périard says.

When you go for a walk on a hot summer day, before you’ve adapted to the heat, both your skin temperature and your core temperature may go up .

That sets off alarms in the body, announcing heat stress.

“With that, we trigger lots of sweating, and we increase our skin blood flow,” says Périard.

Sweat evaporates from the skin, cooling skin down, and blood sent to the surface of the body helps shed heat.