How is glucose uptake during exercise different than glucose

How is glucose uptake during exercise different than glucose uptake immediately following a meal?

Solution

Glucose uptake in the body is monitered closely by the endocrine system and metabolism. Circulatory levels of insulin and glucagon along with the physical state of the body determine the rate and extent of glucose uptake under normal conditions. Physiologically, enhanced insulin levels decrease the total glucose content and deprive the cells of energy producing substrate. On the other hand, increase in glucagon increases the blood glucose levels and makes it available for the cells for metabolism.

However, this scenario is different for cells after exercise. After exercise, the insulin responsiveness of the cells has been scientifically proven to decrease. This is based upon the fact that during/after exercise, the oxygen and energy demand of the body increases suddenly. In order to provide sufficient energy to the body, cells perform extra aerobic respiration by oxidative phosphorylation and hence, require more substrates for generation of ATP. Glucose remains the primary energy source for aerobic respiration. Thus, during exercise and just after completion of it, the glucose uptake rate and extent of the cells, eg. skeletal muscle cells increases suddently irrespective of the circulating insulin status. This irresponsivenss to ciculating glucose represents the acclimatization strategy of cells against enhanced oxygen and energy demand during and after exercise.

Thus, it can be concluded that after a meal, glucose uptake is modulated under the cellular responsivenss towards circulating insulin levels while after/during exercise, the cells tend to lose insulin responsiveness and show high glucose uptake to support oxidative phosphorylation.