Whilst exercising, the heartbeat of a non-athletic individual is faster than that of an athletic individual. The untrained heart beats faster, but less efficiently than that of an athlete. Both the maximum, and the resting heart rate of an athletic individual are lower than the average heartbeat. In a non-athletic individual, the heart rate when resting is about 60 to 90 beats per minute, whilst in athletes it can drop below 40 beats per minute.
> When you exercise, the heart works harder when other muscles in the body pump more blood back to the heart. The major muscles of the legs have large veins that will fill during the relaxation stage of the movement, and the muscle contraction in the active movement pushes the blood back into the circulatory system. Increasing blood flow triggers a faster heartbeat. Because the heart muscle of conditioned athletes enlarges and strengthens, the hearts of athletes pump more blood per beat. 1