Exercise Prevents Colds and Flu

A study published in the British Journal of Sports Medicine
found that regular exercise was associated with fewer upper respiratory infections and less severe symptoms.

Researchers followed more than 1000 adults, between the ages of 18 and 85 years, for 12 weeks in the fall and winter. Compared to sedentary individuals who exercised once per week at most, those who exercised five or more days per week spent 43 percent fewer days with upper respiratory infections like colds and flu. When the exercisers did get sick, they experienced up to 41 percent fewer symptoms.

Reference:

Nieman DC et al. Upper respiratory tract infection is reduced in physically fit and active adults. British Journal of Sports Medicine. 2010 Nov 1.