In August 2020, the world’s hottest temperature ever might have been recorded—
54° Celsius in in Death Valley, California.
Scorching deserts aren’t the only places feeling the heat.
On the other extreme, a Siberian town reached 38° this year—
a new high above the arctic circle.
Places around the world are undergoing
more frequent and intense hot weather.
In 2018, two weeks of heat in Japan caused more than 1000 deaths,
and more than 70,000 hospitalizations.
As temperatures rise, many are at risk—
from elderly people, to those who regularly work outside
on farms and construction sites.
A federal report predicts tens of thousands of deaths by the end of the century
in the United States alone.
But researchers say a majority of heat-related deaths and injuries
can be prevented—with straightforward solutions.
It starts with understanding how heat stroke sets in.
This occurs when the core body reaches about 40° Celsius,
or 3° higher than most people’s average temperature.
When internal sensors tell the brain the body is warming,
blood vessels close to the skin expand to promote cooling.
If this doesn’t lower body’s temperature,
the heart will start pumping more blood to redirect fluids,
and the body will begin sweating.
Humans can sweat up to 2 liters an hour under strenuous conditions.
If a person become dehydrated, the adrenal gland releases a fluid regulating
hormone in the kidneys to reduce urine production.
Too much fluid loss makes it harder for the heart to maintain blood pressure.
If blood pressure decreases, the body's internal temperature can climb rapidly.
People with weaker hearts are more vulnerable to heat stroke.
A crucial step is immersion in cold water within 30 minutes of heat stroke or exhaustion.
Restoring hydration is also important.
But in one study, participants’ thirst was quenched well before they replenished their lost fluids.
Making sure to drink the right amount of water to avoid dehydration, helps the body stay cool.
For outdoor workers in particular, adapting to the heat is key.
The body can adjust to changing conditions quite quickly—
researchers found that after individuals spent just two hours a day
under the hot sun for a week,
their core body temperatures lowered,
and they started sweating at lower temperatures.
Unfortunately, chronic use of air conditioning stunts these adaptations.
Instead, cooling down with a fan,
which is cheaper and requires less energy, is more effective.
Another easy technique is splashing cold water on the skin.
Like sweating, the cold water cools the body as it evaporates,
but without the body’s loss of fluids.
In 2020, an average of 21 days in the summer were too hot for people to work in the United States.
This number is expected to double by 2050.
Research that helps people adapt to the heat—
and know how to respond when things go wrong—
can prevent future deaths