Exercising too hard 'can make you more likely to catch cold'
Doing regular workouts is no doubt good for health, but don't exercise too hard, for researchers claim that it can make you more likely to catch cold and flu.
A team at Loughborough University says that brisk walking daily have been shown to boost immune system and reduce one's chance of catching a cold by up to 30 per cent.
But prolonged strenuous activity such as running marathons could make you between two and six times more likely to succumb to upper respiratory infections including colds, flu, sinusitis and tonsillitis, the 'Daily Mail' reported.
Team leader Professor Mike Gleeson, an expert in biochemistry at Loughborough University, said exercise could have "both a positive and negative effect on immune function and can influence an individual’s vulnerability to infection".
The researchers concluded from examining the last 10 years of research in this area that "moderate" exertion is best for the immune system.
Infections of the nose, throat and sinuses are usually caused by viruses circulating in the environment and whether we catch them depend on how well our immune system can resist them, as well as genetics and aggravating factors such as stress, lack of sleep and poor diet.
The immune system contains Natural Killer cells which recognise cells infected with the virus and try to eliminate them, according to the researchers.
Prof Gleeson said moderate exercise enhances the activity of these cells, where stressful endurance activities such as marathons can turn them down.
"If you have a tendency to be a couch potato then you probably have an average risk of catching an infection -- typically 2 to 3 per year. Research shows undertaking moderate regular exercise can reduce their chances of catching a respiratory infection such as a cold by up to almost a third.
"Moderate exercise has a positive effect on the immune system. So to keep colds at bay a daily brisk walk should help -- it's all about finding a happy medium," he said.
