Fit to drop.

This programme reports on the effects of intense and rigorous physical activity on the human immune system. Dr Lynn Fitzgerald has researched this by working with top athletes and people who take part in triathlons, and concluded that too much exercise produces hormones that weaken the body. Intense activity means the hormones adrenalin and cortisol are produced, which suppress the immune system. Immediately after the activity therefore, the body is weak and prone to catching viruses that normally would not affect it. Dr Fitzgerald found that there was up to a 70% fall in antibodies in the athletes she tested immediately after their triathlon, and she recommends a gentler training regime to build up the immune system.