We already know that exercise helps to prevent heart attacks, strokes, diabetes, obesity and certain cancers, and may extend life span. Now a report from Italy shows that exercise may also help to prevent kidney damage that occurs with aging ( Clinical Journal of Sport Medicine , May 2008).
Doctors measure kidney function by calculating the ability of the kidneys to rid the body of a breakdown product of metabolism called creatinine. Regular exercisers have lower blood creatinine levels and also have kidneys that are better able to clear creatinine from the bloodstream as measured by a test called Glomerular Filtration Rate (GFR).
According to this study, professional bicycle racers have better kidney function than both sedentary people and recreational cyclists. This is very interesting because professional cyclists dehydrate themselves with almost every workout, in spite of the huge amount of fluid they consume. The researchers found that frequent dehydration accompanied by drinking large amounts of water did not cause kidney damage. This repeated stress on the kidneys may even explain why the professional cyclists had better kidney function than the less-active participants.