means "without oxygen." An anaerobic exercise is any
exercise that requires short bursts of power, such
as all-out sprinting or very heavy weightlifting,
which do not require a significant increase in oxygen
delivery to the muscle.
The ability to perform this type of work is dependent
instead on energy sources stored in the muscle. Because
this energy supply is limited, anaerobic exercise
can be sustained for only short periods of time. In
reality, most exercise is a combination of aerobic
and anaerobic exercise. The amount of each is dependent
on how hard and fast the exercise proceeds. With a
primarily anaerobic or resistance exercise such as
sprinting, after about 90 seconds, you begin gasping
for air and feel a burning sensation in your lungs
- your body is forcing you to stop exercising.
Anaerobic training will help your sports performance,
but it won't provide the health benefits of aerobic
exercise. When you push it during an anaerobic workout,
all you're really doing is tiring yourself out early
and cutting short your aerobic training. You'll do
better by slowing down your pace and stretching the
length of your workout.
During an aerobic workout, the point at which your
oxygen supply runs out and you slip into using stored
energy is called your anaerobic threshold. If you
are out of shape, your body is not very efficient
at taking in oxygen, and you hit your anaerobic threshold
while exercising at very low levels of intensity.
In other words, any mismatch between oxygen demands
and your ability to supply oxygen is met by anaerobic
sources until they run out.
As you become more physically fit, you are able to
go farther faster and yet still supply oxygen to your
muscles, with less need to use limited amounts of