Question

sally and jim went to jog 1km a few hours after lunch, which stored fuel would sally probably tap into during those few hours

Answer 1

Any physical activity or strenous exercise increases the demand of energy for the muscles. The immediate energy requirement for the working muscles are fulfilled by the increase breakdown of ATP (energy currency) to ADP molecules. The energy that are released after the ATP breakdown can fulfill the energy requirement only for few minutes because amount of ATP stored are less. In addition to ATP, muscles also store the small amount creatine-phosphate as an energy source.

The energy requirements of the body are fulfill by the three energy systems under different conditions:

1) Immediate system : In this system, the energy sources that immediately fullfilled the energy requirement are ATP and creatine-phosphate which are stored in the muscles.

2) Short term system : In this system, the energy requirement are fulfilled by the anaerobic glucose breakdown (glycolysis) i.e lactate production, glycogenolysis (glycogen breadown) etc.

3) Long term system: In this system, aerobic breakdown of glucose (by glycolysis) and oxidative phosphorylation occurs.

So, while jogging the energy requirements of the muscles are powered by the stored ATP, creatine-phosphate and by anaerobic glycolysis of muscle glycogen.

So, mainly carbohydrate (one of the respiratory substrate) would fulfill the energy requirement during running, jogging or exercise.

The glucose stored in the form of glycogen in the muscles would sally probably tap during those few hours.