Too Much Exercise Can Slow Our Immune Response To Colds
January 6, 2012

Too Much Exercise Can Slow Our Immune Response To Colds

Different levels of exercise can actually significantly increase or decrease your chances of catching a respiratory infection, says Professor Mike Gleeson from Loughborough University.

Regular moderate exercise has been known to reduce the risk of catching cold-like infections, while prolonged strenuous exercise, such as marathons, can make an individual more susceptible, explains Professor Gleeson talking at the Association for Science Education (ASE) Conference on Friday, on behalf of the Society for General Microbiology and the British Society for Immunology.

Gleeson explains why the exercise factor is an interesting one. “If you have a tendency to be a couch potato then you probably have an average risk of catching an infection — typically 2-3 upper-respiratory tract infections (URTIs)s per year, reports The Telegraph.

"Research shows that those undertaking regular moderate exercise (e.g. a daily brisk walk), can reduce their chance of catching a respiratory infection, such as a cold, by up to almost a third. Conversely, in periods following prolonged strenuous exercise, the likelihood of an individual becoming ill actually increases. In the weeks following a marathon, studies have reported a 2-6 fold increase in the risk of developing an upper respiratory infection."

"The heavy training loads of endurance athletes make them more susceptible to URTIs and this is an issue for them as infections can mean missing training sessions or under performing in competitions."

Natural Killer (NK) cells from the immune system are important weapons in the fight against viral infections in that they recognize cells invaded by viruses and force them to commit suicide.

Moderate exercise boosts the performance of NK cells, whereas stressful endurance activity such as running a marathon reduces it. The changes are tightly regulated by stress hormones and other immune cells, said Gleeson.

"Moderate exercise has a positive effect on the immune system. So to keep colds at bay, a brisk daily walk should help - it´s all about finding a happy medium."


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