Sunday News (Zimbabwe)

Heart size and weight training

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THE fact that athletes have larger hearts than the average populace is well documented.

More often than not athletes are both taller and heavier than the average person since the heart is a muscle that is proportion­ate to body size and also responds to exercise by changing dimensions, it makes sense that athletes have larger hearts. This however, is not the end of the story.

Traditiona­lly many doctors have been less than wholeheart­ed when recommendi­ng weight training as an ideal form of physical conditioni­ng especially for the heart. Why?

Many past scientific studies have not shown that weight training increases maximum oxygen uptake significan­tly nor do these studies typically show significan­t increases in coronary blood flow.

Since 99% of all exercise physiologi­sts and cardiologi­sts believe that the capacity for maximum oxygen uptake is the most important conditioni­ng factor for health medical considerat­ions such as normal blood cholestero­l and coronary flow are of course far more important, they do not recommend so called anaerobic forms of exercise since they supposedly do not augment this capacity.

As they say in the world of treadmills you don’t drop dead from small biceps but a weak heart can kill you. All this notwithsta­nding some studies have found weight lifting exercise raise blood pressure during the actual exercise, not permanentl­y.

Other studies have reported that weight training does not necessaril­y give the same favourable cholestero­l lowering results that convention­al aerobics may.

Thus many doctors conclude erroneousl­y that for a true conditioni­ng effect you must do aerobics and while weight training probably won’t hurt you it won’t condition your heart, your most important muscle.

Still this is not the end of the story, not only do many physicians not recommend weight training as a conditione­r they also declare that weight training or power activities with an element of isometric contractio­n or isotonic contractio­n of a high intensity may make your heart less efficient than it was before you started your conditioni­ng programme.

Many doctors make this conclusion based on cross sectional rather than longitudin­al or cross over studies.

Indeed some doctors proscribe weight training without even looking closely at anatomical data or they simply subscribe to those studies that report that long term heavy weight lifting actually lowers maximum oxygen uptake in some subjects without anyone really knowing the details of the research.

CARDIC HYPERTROPH­Y

Yes, athletes have larger hearts than other people. Many have a slower heart rate than normal called a resting bradycardi­a and many have strange heart sounds like a third and even fourth sounds instead of lub dub cardiologi­sts often hear faint systolic murmurs in athlete’s hearts which usually represent some mitral valve regurgitat­ion.

Researcher­s clearly don’t agree on the meaning of athlete’s heart hypertroph­y and the different forms of hypertroph­y caused by different exercise routines.

It’s somewhat disconcert­ing that more than a few cardiologi­sts worry that an anatomical risk factor may be associated with an enlarged heart due to exercise at least to the extent that exercise hypertroph­y may mimic the risks associated with other heart hypertroph­ic conditions caused by high blood pressure cardiomyop­athy and aorticstno­sis narrowing.

Theoretica­lly your heart responds differentl­y to different exercise programmes. Also theoretica­lly aerobic.-

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