Anytime you exercise, your brain releases chemicals
known as endorphins that produce a feeling of euphoria,
which is known as "runners high", which is also very
easy to become chemically addicted to.
Without this rush, you'll feel irritable and out of
it until you exercise again. Therefore, you'll go
on exercising and not listen to what your body is
actually telling you - which is to stop.
The main reason addicts will continue to push themselves
lies in what will happen when they don't work out.
Normally when they are unable to exercise, they will
display signs of depression, anxiety, confusion,
and be less happy with themselves.