Basal Metabolic Rate
The human body is a very complicated engine. We eat food which is the fuel
for life, our body then processes that fuel to keep us running and any extra fuel is stored as fat. In
comparison a car takes in petroleum and the engine burns that as the car is running, any extra petroleum is
stored in the vehicle for future use. There are scientific calculations for working out the energy we take in
and burn and as a result we can work out such things as the amount of energy needed to survive.
The basal metabolic rate (otherwise known as BMR) is the amount of energy
that our bodies use when resting. Resting can be thought of as doing nothing (such as lying down or sitting
on the couch). Our body generates heat as it works to keep us ‘running’, this heat can actually be measured
to work out how much energy we are using.
For someone who is very fit and works out frequently, they would have a very
lean (or thin) body, this correlates with a low basal metabolic rate. As we get older we tend to worry less
about being fit and lean so our BMR actually increases.
Measurement of basal metabolic rate can be very complex indeed, as it can be
hard to actually pinpoint when a human truly is doing nothing. Therefore resting metabolic rate which closely
tied in with BMR is the actual measurement we generally take from humans.
Luckily, careful scientific tests have been carried out for many years now
and there are charts which use humans, weight, sex, and height among other factors to estimate the level of
basal metabolic rate.
The energy output that is measured via out BMR is based on a daily average
of what we might use or require. A majority of this energy is used to keep our body running and normal
processes working correctly, with roughly 20% spent of physical activity and a smaller amount on digestion
(such as the conversion of carbohydrates down to energy).
This subject relates heavily to our biochemistry and at its base the human
body and how it survives. There has been a lot of interest in how our bodies use the fuel (food) to survive
and how much we actually require. The Harris-Benedict formula for example can actually tell us the
amount of calories from food needed to survive.