after you spend a few weeks in a hot climate, your body makes subtle adjustments that help you better tolerate heat stress.2 Your normal deep body temperature drops. Your body sweats at a lower temperature, and so there is less strain on your heart, which keeps your heart rate from rising fast. At the same time, your heart pumps more blood per stroke. Your body retains more fluids and blood volume rises, increasing water reserves for sweating and cooling. But these changes are not permanent. “If you go out of the heat, within a few weeks all the adaptations go back to zero,” says Sam
...more
