The immune system is inexorably linked with exercise – they have an inverse relationship. No exercise has no effect on stress and too much exercise can cause too much stress. Immunity gets poor when stress gets high, so alongside good nutrition and hydration, exercise is an ideal way to keep your immune system on full-tilt. Regular exercise is great for increasing hormonal activity, clearing out waste products and re-energising your body’s cells. Exercise can cause enhancement of key areas of the immune system (British Journal of Sports Medicine, Vol 28, Issue 4 247-255 ), and moderate steady-paced cardio-vascular training fits the bill nicely. A long walk for those of you less accustomed to exercise would be fine, and the fitter you are the harder you will have to work to achieve a similar systematic stimulation which induces the same results. So a gentle run, swim or cycle will be ideal. Remember, though, that heavy exercise suppresses the immune system by placing demands entirely on the completion of the exercise, so if you are a bit under the weather – take it easy! Now you won’t hear that advice too often, so get out there and get moving.