Running from the common cold

The average adult in the United States can expect to have a cold two to four times a year, while children can catch between half a dozen and 10 colds a year, on average, all of which costs the U.S. economy around $40 billion annually.

But we may have a trick up our sleeves: research has found that people who are physically fit and active have fewer and milder colds.

Being older, male, and married, seemed to reduce the frequency of colds, but after taking account of other influential factors, the most significant factors were perceived fitness and the amount of exercise taken.

The number of days with symptoms among those who said they were physically active on five or more days of the week and felt fit was almost half (43% to 46% less) that of those who exercised on only one or fewer days of the week.

The severity of symptoms fell by 41% among those who felt the fittest and by 31% among those who were the most active.

Bouts of exercise spark a temporary rise in immune system cells circulating around the body, the researchers said. Although these levels fall back within a few hours, each bout is likely to enhance surveillance of harmful viruses and bacteria, so reducing the number and severity of infections, such as the common cold.