Fortunately, an investigation completed at the University of Toledo in the United States indicates that swim training may reduce total cholesterol and raise levels of HDL2 cholesterol, the type of cholesterol which seems to play a protective role in thwarting cardiac disease. At Toledo, 10 healthy swimmers (six males and four females) were monitored as they carried out an intensive swimming programme which lasted for at least 15 weeks.

Total cholesterol levels remained at just 145 mg/dl during the 15 weeks of training but soared to 177 mg/dl four weeks after training ended, suggesting that the strenuous training kept cholesterol at bare-bones levels. Also, HDL2 ('good') cholesterol increased by about 50 per cent during the training period and didn't drop off after training ended, again pointing to a positive role for swim training in improving blood-fat profiles.

Unfortunately, the swimming programme was extremely rigorous. Since the swimmers averaged about 27 MILES of swimming per week, it's not clear that less-strenuous training would have such a positive impact on blood cholesterol. Also, body fatness did not change at all during the season, in spite of the heavy-duty training. Overall, it appears that long-duration swimming has the potential to reduce the risk of coronary artery disease, even though its ability to carve away body fat is still controversial.

'Body Composition and Blood Lipids in Male and Female Swimmers, N Medicine and Science in Sports and Exercise, vol. 26(5), Supplement, p. S23, 1994