Why do we get tired ?

After the day’s work, we all get tired. Similarly we get tired after running, swimming or doing exercises.

Do you know why we get tired after doing some work ?

When we do some work at a fast speed,our muscles do not get as much oxygen as they need. In such a saturation to provide extra energy to the body, the glycogen stored in our muscles is transformed into lactic acid through the process of fermentation.

The lactic acid reduces the working capacity of the muscles. This state of the body is known as fatigue. The lactic acid acts as a poison for the muscles. If we expel the lactic acid from the muscles by some process, they can again become for for working.

As a result of the muscular action some other substances called fatigue toxins are also produced in the body. Blood circulates these acids and toxins throughout the body because of which both the body and the brain get tired. Even when we do some mental work lactic acid and fatigue toxins are produced in the body and we get tired.

Scientists have conducted many experiments in this field. A dog was mad to work hard and when it is got tired and went to sleep its blood was transfused into an active dog’s body. The later dog automatically became tired and fell asleep. Similarly if the blood of the active dog is transfused to the body of a tired dog, he immediately became active.

Fatigue is not only a chemical process but is a biological process too. It is a defence mechanism. This tells us as to when to stop work and give rest to the body. Fatigue cannot be removed fast. It is essential to give rest to the cells of the body to remove it.

Sleep is a very effective means to reduce fatigue. This repairs the damaged cells of the body. With the arrival of proper quantity of oxygen in the body through breathing, the lactic acids reconverted into glycogen and we again start feeling fresh. Little rest also removes fatigue to some extent. The loss of glycogen due to fatigue is repleted to some extent by our food also. That is why a tired person feels very hungry .