Exercising In The Heat: 5 tips to help you keep your cool!
On a hot day we may feel like we’re melting, but did you know
that our internal temperature (or core temperature) only changes
by a few degrees. Our normal body temperature at rest is
maintained between 36 and 38 degrees Celsius. Our core
temperature is extremely important as the processes that occur
in our cells need it to be very constant in order to keep the
body alive. In fact, you will require medical intervention if it
drops below 34.4 degrees, or above 41 degrees.
Sources Of Heat
Apart from the obvious source of heat: the environment, the body
also has another major contributor: metabolic processes.
Anything that increases energy production, the release of
hormones, or basal metabolic rate, also increases heat
production.
Body Temperature Whilst Exercising
Body temperature reflects the balance between heat production
and heat loss. As we exercise we increase our body temperature
and for us to be able to continue we must be able to release the
excess heat.
This is done using the circulatory system. The heat is carried
by the blood, to the skin. It is then released into the external
environment.
The release of heat is completed by any of 4 mechanisms:
* Conduction: the heat is transferred through contact with
another object. This object must have a lower temperature. The
body loses only small amounts of heat due to this process.
* Convection: the heat is transferred by the motion of a gas or
liquid (eg, air across the skin when running, or water across
the skin when swimming). As these air or water molecules come
into contact with the body, heat is released to them, they move
on, and are replaced by cooler molecules.
* Radiation: the heat is transferred from one object to another
without contact. This can result in heat loss or heat gain,
depending on the environmental conditions
* Evaporation: heat is transferred through the evaporation of
bodily fluids when brought into contact with the external
environment (eg, sweat evaporating off the skin, and to a lesser
extent our breathe as we exhale). This is usually the most
important form of heat loss during exercise. In this process the
heat is transferred from the body, to water on the surface of
the skin (sweat). When the sweat reaches a certain temperature
it is converted to a gas and the heat is released into the
environment.
What does all this mean to the average exerciser?
The human body’s automatic temperature controls work very well,
but you’ll perform much better if you follow these guidelines:
* Expose as much of the skin as possible to the open air. This
will not only allow the sweat on your skin to evaporate, but it
will also allow some heat loss via convection.
* If you are not able to expose much skin (eg, sports uniform),
then take frequent water breaks.
* Wear cotton clothing whenever possible.
* In extremely hot weather, take frequent rest periods.
* If you do not regularly exercise in hot conditions, take time
to acclimatize before participating in high intensity exercise.
