Question

Why do we feel tired an performing heavy physical work?
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Answer 1

Answer:

Simple muscle fatigue, from physical effort, is a direct result of using up the glycogen stored in the muscles. Glycogen is the main source of energy in your muscles and as it is used up, toxic waste compounds build up in the body and there is a general loss of energy.

Answer 2

Simple muscle fatigue, from physical effort, is a direct result of using up the glycogen stored in the muscles. Glycogen is the main source of energy in your muscles and as it is used up, toxic waste compounds build up in the body and there is a general loss of energy.