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How the heart responds during exercise

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Introduction

How the heart responds during exercise Several things happen to your heart while you exercise. First, your heart rate, that's the number of times your heart beats per minute, increases to pump more blood to the muscles all over the body which are working harder. Therefore, your cardiac output increases. This is the amount of blood that the heart pumps out to the body. The heart rate and the cardiac output are proportional to each other. The other factor in this proportional equation is the stroke volume. The stroke volume is the amount of blood pumped out of the heart with each contraction of the ventricle. An average adult's stroke volume is about 70ml. When resting, the heart has a cardiac output of about 5 litres. ...read more.

Middle

Your heart would not be able to maintain this level of activity for a long time. So how do athletes train their hearts to work extraordinarily hard without them packing in? When the heart is exercised regularly it becomes larger and the volume of the chambers increases, as does the stroke volume. The heart of a trained athlete can pump more blood, and therefore more oxygen and nutrients, to the working muscles in the body each time the ventricles contract. So each beat of the heart pumps more blood than the average person, because the heart is larger. Therefore, it will require less effort by the heart to do ordinary things like walking up a flight of stairs or running for the bus. Just like a weight lifter uses less effort to lift 50kg than an average person does, the heart can pump more blood at a slower rate when demands are made upon it. ...read more.

Conclusion

After all, different people have different boundaries - the heart of a 70 year old person will generally be less strong than the heart of a 20 year old person! There's usually a formula for everything, and this is no exception! Your maximum HR should be 220 - (your age). But working at your maximum heart rate all the time would tire your heart out very quickly. Therefore, your training rate or Target Heart Rate (THR) should be 75% of your maximum HR. So for a 15 year old person: 220- 15 = 205bpm (max HR) 75% of 205 = 154bpm (THR) So 154bpm would be the Target Heart Rate to maintain during your aerobic workout, after a warm-up. To get the best results, you should do aerobic exercise to raise your heart rate to this level for at least 20 minutes, three times a week. Aerobic exercise includes things like swimming, running, cycling, playing football or basketball, or dancing. ...read more.

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