What causes heart rate to remain high after hard exercise even though effort is reduced?

Answer 1

This could be due to dehydration. The heart will pump faster when your body fluid level is low. You may also be exercising beyond your effective heart rate range. Or, you could have a more serious problem. If in doubt, you should seek the advice of a physician. Using a heart rate monitor during exercise can also be effective.

Answer 2

Your heart beats fast after a race because running requires more energy than usual. Therefore, using energy requires your muscle to use more oxygen. And what does your heart do? Delivers the oxygen (in the blood) to all the muscles that need it. OK, so to answer your question... Muscles require more oxygen than the heart usually provides, so the heart beats faster to deliver the sufficient amount of oxygen.

Answer 3

The time for HR to fall to resting levels depends on the interaction among autonomic functions, the level of physical fitness, and also on the intensity of the exercise. Recovery can take one hour after light or moderate exercise, four hours after long-duration aerobic exercise, and even up to 24 hours after intense or maximal exercise. The mechanisms responsible for such discrepancies as to the time needed for total HR post-exercise recovery are not fully clear, and the following explanations are currently considered as the most plausible: decreased vagal activity, sympathetic overactivity or even increase in the activity of both ANS branches, recovering balance with slight vagal predominance. Five minutes after a moderate to intense exercise session, serum norepinephrine is still higher than when in rest, suggesting higher sympathetic activity at this stage. However, one must take into account a latency time of about 2.5 minutes for serum norepinephrine to reach its peak, leading us to wonder that the five-minute recovery time of this study could be too short. It seems that with aging, the time to norepinephrine be removed from the blood is slower, and cardiac rhythm remains faster for a longer time after the exercise. The decrease of post-exercise norepinephrine concentration comes along HR decrease, but there is indication that at the beginning of recovery, vagal modulation is primarily responsible for HR fall.