Fitness Clubs Ada OK
Infections, the Immune System, and Cycling
Being in shape and remaining physically active are usually considered synonomous with staying healthy, so at first this section may seem out of place. However, as in all sports, bicycling has the potential for negative health impacts as well. These include general risks associated with all vigorous and prolonged exercise as well as cycling specific injuries. And because of the varied ecosystems one can explore on a bicycle, infectious diseases are a hazard as well.
HEALTH BENEFITS OF EXERCISEThere is little question that aerobic exercise for 20 to 30 minutes, four times a week improves cardiovascular health and decreases cardiac disease. The only question is "how much is enough"? One recent study of 1000 middle aged men followed for 11 years demonstrated that those who burned fewer than 800 Calories a week in leisure activity (equal to 20 miles of cycling) were 3 1/2 times more likely to have died of a heart problem than those men who expended 2100 Calories per week in aerobic exercise (approximately 50 cycling miles).
Although cardiovascular disease is mentioned most often, there are many other health benefits of regular exercise. Various long term studies have indicated a decrease in cancer rates - one analysis of exercise and breast cancer suggests that recreational physical activity alone decreases a woman's chance of developing the disease - as well as an improvement in mental health and a decrease in depression.
IMMUNE SYSTEMThe immune system consists of a complex, interactive grouping of cells, hormones, and other molecular modilators that defend the body from the invasion of foreign cells - whether it be infectious organisms such as viruses or bacteria, or abnormal cells such as cancer cells. Moderate aerobic activity is felt to have a beneficial effect (compared to a sedentary lifestyle) while overtraining and exercise to exhaustion (a marathon for example) are felt to be detrimental - a "J" shaped curve if one graphed out infection rates versus intensity of exercise. This can be a particular problem in the fall and winter months when respiratory infections are more common as people congregate in enclosed areas at work and in school.
A study of upper respiratory tract infections (URTI) in athletes nicely supports this contention. A recent study by Matthews et al demonstrated a 20% reduction in URTIs in a group of regular, moderate exercisers. In contrast, a study in a group of marathoners (an example of exercising to exhaustion) did demonstrate a significant increase, a 13% incidence of URTIs in the week following the event compared to 2% in the comparison group that enrolled but did not compete.
Is it possible to identify why extreme exercise has this neative effect? Although significant changes in the level and functional activity of immune system parameters have been observed in athletes, investigators have had little success in linking these to a higher incidence of infection ...