|Normally our body burns calories to keep us warm.
When we feel cold, does our body burn more
calories than usual? Do we need to burn more
calories during winter just to keep our bodies at
our normal temperature? If a person gets an
infection and the body temperature rises, do we
need to burn more calories in order to increase
Yes, more calories are being burned to keep a
normal body temperature in a cold environment.
Heat is constantly transferred from your skin to
the environment, as long as it’s colder than your
body’s temperature outside. This heat needs to be
replaced somehow, otherwise you would get
hypothermia. There are specialized cells
called brown fat cells which help generate
this heat. Whenever your body makes energy, there
is always a small amount that is released as heat.
In brown fat cells, their energy-making process is
“leaky” so most of the energy is released as heat,
rather than chemical energy that can be used
later. Additionally, you can activate a large
number of muscles to cause shivering which
increases body temperature by expending a large
amount of energy, some of which turns into heat.
Shivering is basically like exercising in place
that raises your body temperature when you’re
cold. When you get a fever (usually because of
an infection) your body does need to burn a lot of
energy. This is a result of conservation of
energy; if your body is hotter, it has more energy
and that energy needs to come from somewhere. When
you have a fever, you often feel cold. This is
because your body has changed what normal is from
around 98 degrees F to greater than 100 degrees F.
As long as you’re below this normal point, you’re
going to feel cold and as a result, going to
shiver. It’s thought that the high temperature
of a fever interferes with virus reproduction as
well as increasing the efficiency of the human
In short, yes. Your basal metabolic rate,
which is the daily amount of calories you burn by
just existing, increases a tiny bit when it starts
to get colder. That’s because your body needs to
try a little harder to stay warm. On top of that,
things like shivering increase calorie expenditure
considerably more. For the most part, though, the
extra calories burned by the cold weather are
minuscule in comparison to the amount burned by
things like activity or exercising.
Infection does raise body temperature, usually
causing a fever. A fever is the body’s defense
against the infection. When your body
temperature increases considerably, so does our
metabolism. As each degree of temperature
rises, energy demand from the body increases,
which is why intake of food is important when sick
to fuel and help heal the body.
Yes, our bodies burn more calories in cold
weather to keep warm, and yes, our bodies burn
more calories to increase our temperature when we
have fevers. This is, in fact, why you feel
tired when you have a fever: you are burning
all of your energy to give yourself that extra
boost in temperature.
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