INTRODUCTION

There are two types of exercise; STEADY e.g. a slow cross-country run, and INTENSE e.g. a 200m sprint.

STEADY EXERCISE

Steady exercise is when sufficient oxygen can be breathed in to satisfy the needs of the muscles. Oxygen is required by the muscles to clear away waste products that are formed during the contraction of muscle.
During steady exercise, the muscles use mostly fat for the creation of energy, but also glucose. As long as the glucose supplies last, the body can continue the exercise quite comfortably. However, when the glucose is all used then the body has to continue on fats alone. The effect of this is a build up of acid in the blood stream, and heavy sweating resulting in dehydration. The body cannot continue due to a rising of temperature and the person has to stop. If he attempted to continue, he would eventually collapse and probably lose consciousness.
Once body temperature has dropped, then further exercise is possible but only for a very short time as the temperature will immediately start to rise again. It is important that a performer in this condition drinks some fluid as soon as possible.

INTENSE EXERCISE

When the level of exercise reaches the stage where the amount of oxygen breathed in is insufficient to clear away the waste products formed by the muscle contractions, then an oxygen debt builds up. The waste products (mainly lactic acid) continue to build up causing pain in the muscles and breathlessness. fairly soon, the performer has to stop or at least slow down. The rate of breathing will stay very high until the oxygen debt has been paid off, i.e. the waste products have been cleared away.
In intense exercise, no fat is used because fat can only be used as a muscle fuel if there is a plentiful supply of oxygen. In intense exercise, all the oxygen is needed to try and clear away waste products. So in intense exercise the muscle fuel is nearly all glucose.

BENEFITS OF EXERCISE TO THE CIRCULATORY SYSTEM

1] INCREASE IN BLOOD VOLUME

2] HEART MUSCLE BIGGER AND STRONGER

3] HEART MUSCLE BETTER SUPPLIED WITH BLOOD

4] HEART'S WORKLOAD REDUCED

5] LESS CHANCE OF HEART DISEASE

6] INCREASE IN CAPILLARY NETWORK SO MORE EFFICIENT EXCHANGES

(Improved Tissue Respiration)