Tab commenced 03 August, 2009
Introduction — Why Run/Exercise?
RUNNING AND EXERCISE can affect almost all of your body’s functions, and usually for the better. To introduce readers to the science and biology of the effects exercise has on the body, which I believe to be a good starting point on this area of work, you will no-doubt note the diverse range of benefits accrued from maintaining a regular programme of exercise:
Ageing: Recent studies have shown that your physical decline is just 2-5 per cent per decade. The fact that it is more pronounced in older people is because of inactivity. If you run or exercise regularly between the ages of forty and fifty, you may lose as little as 2 per cent of your capacity, and if you increase your fitness training over that time, you may even get fitter.
Body fat levels: The average man has 22 per cent body fat, the average woman 27 per cent – levels that running and exercise can reduce quite quickly. Running even three times per week for 30 minutes each session can burn over 1,300 calories per week – a possible 17 pounds of body fat lost in a year. And, increasing mileage or the duration of gym sessions can significantly add to that loss.
Bones: Moderate amounts of running tend to increase bone thickness in the feet and legs, although high-mileage runners (i.e. those running over 50 miles per week) can have thinner spines, for reasons which aren’t scientifically clear. For those athletes who do train at this level make sure you do some weight training exercises which stress the spine, in order to strengthen it.
Women runners who train heavily are at risk from osteoporosis in later life. Osteoporosis (literally ‘porous bones’) is the disease which causes the majority of broken bones in elderly people, and women are eight times more likely to suffer from it. Amenorrhoea can also occur in women, particularly if training is heavy, and is an added risk because amenorrhoea reduces bone density. The answer, though, is to maintain a sufficient calcium intake, and to have regular medical check-ups.
Brain: Besides the release of endorphins – responsible for the so-called ‘runner’s high’, senses of calm and wellbeing – studies have shown that running and regular exercise enhances mental functioning: maths and reasoning test scores are higher if done after training sessions.
Circulation: During exercise most of your body’s organs and tissues, except those directly used, are drained of blood. However, during recovery, it’s the opposite story: arteries and veins expand to cope with the higher volume of blood, and direct this blood more efficiently to any organ which needs it.
Electrolyte balance: Generally, running and exercise is likely to lead to improve blood flow to the kidneys, which allows them to keep better tabs on blood electrolyte levels and decrease the risk of deficiencies. However, during periods of hot weather, electrolytes are likely to be lost through increased sweating. Keeping well hydrated with a sports drink, though, does replace lost electrolytes in the blood, essential if performance is to be maintained and the avoidance of cramp and fatigue.
Heart and blood pressure: After running or exercising for a few months, your heart’s walls thicken and the ventricles (internal chambers) increase in size. As a result more blood is sent to your lungs with each heartbeat, and resting pulse can decline by 20 percent or more.
Scientific analysis has shown that if you run for 145 minutes per week, you are 40 percent less likely than a sedentary person to have a heart attack. If you’re overweight when you start running, then the resulting weight loss will lower your blood pressure, taking some of the strain off your heart.
Hormones: If you run above your lactate threshold pace (slightly slower than VO2 max) your body tends to produce more human-growth hormone, which boosts muscle building, accelerates fat breakdown, and speeds the repair of bones and connective tissues.
Running and regular exercise also seems to increase muscle cells’ sensitivity to insulin, a key hormone released by the pancreas. In Type-I diabetics, this improved sensitivity can reduce insulin requirements; in Type-II diabetics, it decreases insulin resistance and promotes normal blood-glucose levels. Running also increases blood levels of a thyroid hormone called thyroxin, which increases protein synthesis, boosts mitochondria production, particularly within the muscles, and encourages the breakdown of fat.
Joints: Running and exercise lubricates the joints to keep them supple and friction-free, but can lead to deterioration of the joint if disease or ageing of the joint is already present.
Lungs: Actually you can’t improve the function of your lungs through training. They are already ‘over built’ for even the most strenuous training, and fail to rush oxygen into your blood when you are working hard only because they are too ‘stiff’ to expand and bring in air at high enough rates. You can, however, improve the function of your respiratory muscles – the diaphragm and the muscles which run between your ribs – which makes breathing feel easier as you get fitter.
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© Mark Dowe 2009: all rights protected
