Some people are known to be affected easily by an illness while there are others who rarely fall sick or catch cold. Well, the simple reason is that people who are less likely to fall sick are usually the ones who have a strong immune system.

However, the reason why some people have a strong immune system could be easily pointed out by a study that was conducted at the Appalachian State University in Kannapolis, N. C. According to the researchers of the study, it was found that people who exercised at least five times in a week or felt fit were less likely to fall sick in comparison to rest of the people.

In the study, scientists kept a track on a group of adults for a period of three months. In the time period the physical fitness levels and sickness levels of the patients were scrutinized by researchers. It was found after three-months that on average patients suffered from 13 days of cold in winter and eight days of it in autumn. However, in contrast fitter participants were found to report half as many days of sickness in contrast to average people.

Apart from the days of illness, the fitter bunch of people was also found to be suffering from less severe symptoms of the flu. The scientists have stated that the reason, why fitter people were less likely to suffer a cold was because after exercising, the immune system got a boost and became more active, which resulted in better protection of body from viruses that cause a cold.