One remarkable change in recent years is that millions of people worldwide spend several hours a week in vigorous exercise. Ask any jogger the reason for running a considerable distance, come rain or shine, and the answer almost certainly will be. ‘It makes me feel so good.’
Exercise of this kind, which makes the heart and lungs work harder, undoubtedly has a euphoric effect – provided, of course, that the program has a doctor’s approval. Jogging, cycling, swimming and fast walking, all of which work the heart and lungs, are known as aerobic exercises. They force the cardiovascular system to deliver more blood and oxygen to feed the increased needs of the muscles. The heart eventually becomes more efficient, delivering more blood and oxygen with each stroke.
A slow heart rate is often a sign of long term athletic activity. A world-class runner may have a heart beat as low as forty strokes a minute, less than half the average. If the heart beats more slowly and more efficiently, we art and tear on it and the the arteries are clearly reduced. As disorders of the cardiovascular system head the list of fatal diseases many countries, any move to cut their toll is beneficial. Because the heart pumps harder during exercise, the blood surges through the arteries. This, say some doctors, discourages plaque, a substance that coats the artery walls, hindering the blood flow and often causing heart attacks. Exercise may stimulate the brain to release the brain to release endorphins, painkillers with a similar structure to morphine. As well as their analgesic effect, endorphins are believed to help control stress and mood. This may explain why so many people feel better mentally after work-out: it isn’t, as cynics claim, an overdose of superiority complex.
Exercise helps to build bones and improves the muscles. Stronger bones ward off the dangers of the degenerative condition know as osteoporosis. A larger muscle is more efficient, more flexible and procedures more energy. Better muscles help us to work with less fatigue.
A range of other exercises – isometric, isotonic and isokinetic – strengthen the muscles and make the body more supple.