In a study published in the Korean Journal of Family Medicine, people who did regular, moderate-intensity exercise, such as brisk walking, were 27% less likely to contract a cold than those who didn't exercise. Regular exercise boosts circulation and increases infection-fighting white blood cells – but only venture outside if you're fit and well, with no symptoms such as a fever or cough.

Now find out how what you eat can affect your mood – and how to eat yourself happy

Last updated by Dominique Ayling.

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