According to Prof. Tim Noakes, asports and exercise expert from the University of Cape Town, South Africa, mild exercise can enhance the immune system in at least three ways:
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By stimulating the immune system to release a protein which increases the body temperature. This makes the body a hostile environment for viral and bacterial infections.
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By encouraging the production of the anti-viral protein, interferon.
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By increasing the activity of natural killer white blood cells.
Other studies back up the theory that exercise is good for immunity. Research published in the New England Journal of Medicinestates that:
‘Regular exercise, including daily brisk walking, is associated with a lower risk of several cancers and with lower risks of tumour recurrence and death among survivors, particularly of colorectal and breast cancers.’
However,while moderate exercise has been shown to have many health benefits, excessive exercise can stress the body. Dr Danica Bonello-Spiteri, a consultant in sports and exercise medicine warns that prolonged exercise can lead to increased concentrations of stress hormones:
‘High training loads can suppress the body’s immune system and increase the risk of an athlete contracting an upper respiratory tract infection (URTI).’
So the advice to runners looking to gain most benefit from their exercise should be to include sufficient rest periods to allow the immune system to recover.