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The Exercise Myth
Part 2: Exercise, heart disease and diabetes
has been suggested that regular exercise will enlarge the arteries, thus lessening the likelihood of their becoming blocked and so reducing the risk of coronary heart disease. It was noted in the 1950s that bus drivers had a higher incidence of coronary heart disease than bus conductors and, as the drivers had a less energetic working life, this may be seen to support the argument. It was also noted, however, that dock labourers had higher rates of heart disease than building labourers which tends to defeat the argument as the amounts of exercise associated with their jobs are not likely to differ significantly.[11]
A graph of the early mortality trends from heart disease with radio and TV licences issued at the time shows a strong linear relationship and it too may suggest that a lack of exercise could be connected with the rise.
The claim that exercise may help in heart disease arose from the fact that seasoned athletes develop increased cardiovascular capacity. But the view that exercise necessarily protects against heart disease, a strongly emotive factor in the increasing pressure to indulge in high-intensity exercise regardless of physical status, can be dangerous.
Multiple recommendations for exercise rarely make a distinction between moderate and extreme exercise; they give no warning that the latter causes cardiovascular disease and arrythmias that lead to sudden cardiac death.
There is no placebo for exercise. People who are healthy do more of it; those who are unwell do less of it. And they are usually instinctively correct.[12]
The studies disagree
The results of the major studies published so far have found for the most part that there is no convincing correlation between exercise (or the lack of it) and heart disease. For example, a 4-year study of 16,882 executive grade civil servants aged 40 to 64 suggested that heavy work such as swimming or gardening may be beneficial if continued for over 15 minutes, but its results were inconclusive.[13] Even when accurate reporting of the effects of voluntary exercise on heart patients is examined, the benefits are minimal.[14]
In the UK Heart Disease Project, a part of the WHO European Study, however, the results were conclusive – and different. The Project studied 18,210 men, again in the ‘coronary’ age group, from 24 factories across Europe. Half were given the conventional advice on exercise and overweight, the other half being given no specific advice. The results of this study, published in 1983 showed that instead of the expected benefits, the group which followed the advice on exercise had significantly higher rates of cardiovascular mortality and morbidity than that which did not.[15] These results confirmed others that had been published in the USA a few years earlier.
Data from the United States indicated that richer people tend to adopt health innovations more readily than poorer people, and this was particularly evident in the cases of smoking and exercise. Stern cites a dramatic illustration of the lack of benefit. Some 10,000 people participated in the New York Marathon. Of those, 80% had college degrees and of these half held graduate degrees. Stern points out that ‘Since in our society, whites are generally of higher socio-economic status than either blacks or Mexican-Americans, one might have expected that they would experience the steepest CHD mortality declines. . . . The data, however, indicate the reverse has been true.’
The statistics from the period show that while mortality in the USA from CHD declined by over 20% between 1968 and 1976, it seems that exercise increased the death rate.[16]
There may be a very good reason for this. I was in Ciechocinek, Poland in late 2005, visiting Dr Jan Kwasniewski, whose dietary ideas are exactly the same as mine. Amongst other things, we discussed exercise and I was introduced to a work that has probably never been seen by any Western doctor: a book published in East Germany in 1957, during the Cold War. One chapter demonstrated that the more work limbs and muscles do, the more cholesterol is found in the walls of the arteries that supply them.[17] Or, to put it another way, work may well increase atherosclerosis, the very process that is believed to contribute most to a heart attack. In which case, if you believe in the cholesterol hypothesis, exercising muscles such as the heart that are already hard at work even more, could be considered a form of suicide.
There is an alternative hypothesis: that the cholesterol is in the artery walls as a protective substance, in which case we want to encourage it by taking more exercise and making the heart work harder. But if that increases atherosclerosis as evidence on thiswebsite suggests it will, doesn’t that destroy the case for atherosclerosis as a cause of heart attacks?
Exercise doesn't prevent diabetes
We are also advised to exercise to prevent type-2 diabetes. Sir Steve Redgrave was such an ardent exerciser that he won Gold Medals for rowing in 5 consecutive Olympic Games. But that didn’t stop him becoming a type-2 diabetic in his 30s.
Part 1: Exercise for weight loss | Part 2: Exercise and heart disease | Part 3: Dangers of Exercise | Part 4: References
Last updated 6 February 2010
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