(Ivanhoe Newswire) — The average American adult typically has a cold two to four times a year, while children can catch between 10 and 12 people per year, totaling in about 1 billion colds per year in the U.S. All common colds cost the U.S. economy around $40 billion dollars every year. This study shows that colds can be reduced in frequency and severity with more physical activity.
The study was conducted on 1,000 adults up to the age of 85. Their respiratory health was tracked for 12 weeks during the autumn and winter of 2008. All the participants reported back on how frequently they aerobically exercised, and rated their fitness levels using a validated 10-point scoring system. They were also asked about lifestyle, diet, and recent stressful events, since these can all affect immune system response.
In autumn, the number of days with cold symptoms was 8, and in winter 13 days were reported.
Being older, male, and married, seemed to reduce the frequency of colds, but after taking into account other influential factors, the most significant factors were perceived fitness and the amount of exercise done.
The participants who said they were physically active at least five days a week and felt fit reported almost half as many days with cold-like symptoms, compared to those who exercise at most one day a week. The severity of symptoms fell by 41% among those who felt the fittes,t and by 31% among those who were the most active.
Exercise sparks a temporary rise in immune system cells circulating around the body. Although these levels fall back within a few hours, each bout of exercise is likely to increase the awareness of harmful bacteria and viruses, therefore reducing the number and severity of infections like the common cold.
SOURCE: British Journal of Sports Medicine, published online November 1, 2010