As you can see, my pulse rate increased with the level of exercise I did. For example, the sprint made my pulse 200% faster than the slow walk.
But why did this happen?
Well, it’s quite simple really. Muscles need energy to perform. They get this energy through a process called respiration. When you breathe in, oxygen passes into your lungs, and is able to diffuse into your blood through small cells called alveoli. The oxygen combines with a substance in your red blood cells called hemoglobin. This forms a new substance called oxyhemogobin. The heart then pumps this oxygenated blood around the body, whilst the oxygen diffuses into the muscles all around the body, giving energy to your body. The harder you work, the more oxygen your muscles need, obviously. Therefore, more oxygen must be pumped around your body, making your heart work faster. This increases your pulse rate.
There are specific names for the intensity of your exercise.
∙ Aerobic – long term exercise, for example, marathon running. Using a substance called glycogen, which your body converts from glucose found in carbohydrate food products such as pasta, it uses short energy amounts. In this investigation, it was used in the slow jog, among other activities.
The formula for aerobic exercise is Oxygen + Glucose = Energy + C02 + H20.
∙ Anaerobic - sprinting and short-term exercise that uses a lot of energy quickly. This is most commenly used by athletes competing in 100 meter or 200 meter events.
The formula for anaerobic respiration is:
Glucose = Energy + Lactic Acid
Lactic Acid is a substance that builds up in your muscles that stops them from performing after a certain point. Lactic Acid forms when the body doesn’t have enough oxygen to perform, and can’t be avoiding when sprinting.
How Does Fitness Level Affect My Pulse Rate?
A person of high fitness is able to compete more, because his/her heart is more efficient. For an unfit person, or someone who fails to exercise regularly, the heart is not very efficient; your pulse rate skyrockets, because your heart is not strong enough to cope with too much exercise. By training regularly, several things happen:
∙ The volume of the heart increases
∙ The heart walls get thicker.
∙ Recovery rate increases.
∙ Lower heart rate.
∙ Volume of blood increases.
∙ Your vital capacity increases.
∙ Your intercostals muscles and diaphragm become stronger.
∙ More alveoli are available for gaseous exchange.
∙ More capillaries grow around the alveoli.
So overall –
Oxygen gets to the muscles quicker, and you get rid of carbon dioxide quicker.
Conclusion -
In conclusion, this piece of coursework has taught me a very strong link between exercise and pulse rate. As the intensity of your exercise increases, your pulse rate does too. Also, the level of fitness you have determines a lot about your pulse rate.
By Al Horner, June 2003.
GCSE Coursework – Biology.
