3. When you exercise or take part in a strenuous
sport you will notice several changes taking
place in your body:
1. Your heart beats stronger and faster
2.Your breathing quickens and deepens
3.Your body temperature increases
4.You start to sweat
5.Your muscles begin to ache
4. 1. YOUR HEART BEATS STRONGER AND
FASTER
During exercise it is mainly ADRENALINE
that produces changes in the heartbeat.
Adrenaline is a hormone which causes the
heart rate to quicken.
5. 2. YOUR BREATHING QUICKENS AND
DEEPENS
You breathe quicker so as to get more oxygen
into the lungs. An efficient heart can then
transport this to the working muscles.
Training can be of great benefit to the
Respiratory System. The capacity of the lungs
is increased, which allows more oxygen to be
taken in per breath.
6. Problems produced by exercise vary according
to the type of sport or event.
Problems for the sprinter are different from
those of the middle distance runner. A short
distance sprint may cause little problem to a
trained sprinter, but a games player, who has
to repeatedly sprint, needs to train to cope
with this.
7. The middle distance runner may not be running
fast enough to get out of breath, but if they
have to run up a steep hill, as in x.country,
they may get somewhat breathless.
The same could be said for the 5000m runner
required to produce a sprint at the end.
The problems of a Marathon runner are quite
unique. Here the emphasis is on stamina. It is
not more oxygen that is needed but stored
food. The problem may not lie in getting
breathless, but in having enough stored up
glucose and fat in reserve to keep going.
8. 3. YOUR TEMPERATURE INCREASES
When we exercise, our muscles are working
and they generate heat, so our body
temperature rises.
Body temperature is regulated by heat
radiating from the skin and water evaporating
by sweating.
When we shiver, our muscles are working to
produce heat in order to raise our body
temperature.
9. 4. YOU START TO SWEAT
As we have just seen, some of our energy is
turned into heat. The body will tolerate a small
rise in temperature, but very soon we begin to
sweat.
If the conditions are hot, we sweat more and
produce less urine. We also lose salt as well as
body heat and water.
We have to replace the salt so that the body
stays the same, otherwise we will get CRAMP.
10.
11. It is now common to see drinks being taken
during football, tennis, cycling and many other
games that go on for a long time, in which
competitors sweat a lot. This prevents
DEHYDRATION.
12. 5. YOUR MUSCLES BEGIN TO ACHE
As we now know, in order to work, muscles
need energy. Energy comes from food, which is
mainly converted to GLUCOSE (Sugar)
To work more efficiently muscles also need
plenty of oxygen.
Glucose and oxygen are brought to the muscles
in the blood.
13. Wastes such as carbon dioxide are carried
away in the blood.
This process of getting energy is called
RESPIRATION.
Glucose +oxygen = Energy + CO2 + Water
When muscles do extra work more Glucose and
Oxygen are needed, so more blood must flow
to the muscles.
So the heart beats faster.
14. Eventually it becomes impossible to get enough
oxygen to the muscles, so they use a different
method of getting energy.
Glucose is still used, but now there is a waste
product called LACTIC ACID.
LACTIC ACID is a poison. After a while it will
make the muscle ache, and the muscles will
stop working.
The athlete has to rest while the blood brings
fresh supplies of oxygen to the muscles.
25. EFFECTS OF REGULAR
TRAINING AND EXERCISE
1. THE HEART PUMPS MORE BLOOD PER BEAT.
2.THE RECOVERY RATE BECOMES QUICKER.
3.THE RESTING PULSE RATE BECOMES LOWER.
4.THE NUMBER OF CAPILLARIES INCREASES.
5.THE CARDIOVASCULAR SYSTEM BECOMES
MORE EFFICIENT.
29. Some idea of fitness can be gained from the
resting pulse rate ( RPR ) because with
training, our heart gets bigger and stronger,
and it can supply the same amount of blood
with fewer beats.
However, the RPR does not tell the whole story
because it is just as important to know how
long the pulse rate takes to get back to normal
This is known as our RECOVERY RATE and the
quicker this happens the fitter we are.
30. LONG TERM BENEFITS OF EXERCISE
1. It reduces the risk of coronary heart
disease.
2.You can work harder for longer
Exercise improves the Cardiovascular system
and helps to reduce blood pressure.
As we saw earlier, it helps to reduce stress
and burns off excess calories.
31. If we are keen to get fit, this will probably
motivate us not to smoke. Smoking is the
biggest cause of CHD. So this is a longer-term
effect of exercise.
Over a period of time we can see that the
heart of a fit person will beat far fewer times.
This makes it much more efficient and causes
less stress to be put on the heart. This is also
a long-term effect of exercise.
32. With training the heart muscle increases in
size, thickness and strength, the chambers
increase in volume and so the whole heart gets
bigger.
Therefore we can work harder for longer. This
is yet another long-term effect of exercise.
