As a domain expert in human physiology, I can explain that muscles primarily rely on
oxygen to produce energy during physical activity. This process is known as
cellular respiration. When you exercise, your muscles demand more energy to function, and they use oxygen to convert glucose into a usable form of energy called adenosine triphosphate (ATP). However, muscles can also work anaerobically, which means without oxygen, for short periods of time or high-intensity activities. During anaerobic activity, muscles produce ATP through a less efficient process that doesn't require oxygen, but it also results in the production of lactic acid, which can cause muscle fatigue.
read more >>