Why is the pulse rate higher in heavier/fatter people before and after exercise?

3 responses so far ↓

• 1 Charlotte W // Jul 24, 2008

  cos they gotta work harder. It takes a lot more effort for them to move so they need more energy. Resulting in them needing more oxygen (and glucose). Basically cos dey fat. lol

• 2 Duncan // Jul 24, 2008

  When you move around and exercise your muscles need oxygen and they produce waste products, most notably lactic acid and carbon dioxide. The more weight the muscles bear the more energy is required to bear that weight and therefore the more energy must be produced by the muscles. The muscles will of course use up the oxygen more quickly and produce waste products more quickly.

  It's the removal of these extra waste products that causes an increase in heart rate and breathing rate. A person who is doing more work every second than the average is going to need to remove more carbon dioxide from their blood per second as well, that's accomplished by moving the blood round faster and breathing more heavily. When a person exercises they of course rapidly increase the anaerobic component of their muscle metabolism which causes a massive increase in carbon dioxide and lactic acid…they will of course rapidly increase their breathing and heart rate but also their muscles will become fatigue considerably more quickly as well, not because they are doing more work (a slim person could lift the same weight on a barbell for longer than a fat person could lift their arms up) but because the lactic acid fatigues muscles far more quickly.

  The production of lactic acid also produces what's known as an oxygen debt. Lactic acid production is an alternative way to produce energy when not enough oxygen is available for complete respiration, however the lactic acid still needs to be completely metabolised once exercise has stopped. The metabolism of lactic acid produces carbon dioxide again in the same way as aerobic exercise would and therefore the breathing rate of someone who has produce a lot of it (i.e. a fat person) will remain higher for longer due to that increased need to remove carbon dioxide from the blood.

• 3 koo ching // Jul 24, 2008

  I think because it requires them to use more energy than the average weighted person during exercise, thus requiring more oxygen to get pumped around to all their cells. This extra pumping of oxygen in the blood to all the cells of the body is what causes the high pulse rate.

  Hope this helps!!

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