Very prolonged bouts of exercise and periods of intensified training are associated with increased infection risk. Acute bouts of prolonged exercise cause a temporary depression of various aspects of the body’s immune system reducing its ability to fight opportunistic infections and this may last for up to 24 hours after exercise. Most illness episodes in athletes occur during periods of prolonged heavy training and at times of major competitions this can impair their exercise performance.
Improving rates of recovery
Probiotics are food supplements that contain live microorganisms which when administered in adequate amounts can confer benefits to the health and functioning of the digestive system, as well as modulation of immune function. In the general population, studies have shown that probiotic intake can improve rates of recovery from diarrhoea, increase resistance to gut and respiratory infections, and can alleviate some allergic and respiratory disorders. Our recent research in athletes indicates that some strains of probiotic can be effective in reducing the incidence of the common cold.
Athletes can minimise their risk of infection by avoiding close contact with people who are showing symptoms of infection, by practising good hand, oral and food hygiene, and by avoiding sharing personal items such as towels and drinks bottles. Getting adequate recovery and sleep is also important as is avoiding deficiencies of protein and micronutrients (particularly iron, zinc, and vitamins A, D, E, B6 and B12) which are essential for maintaining normal immune function. Athletes are advised to ingest carbohydrate (30-60 grams per hour) during prolonged training sessions, and consume – on a daily basis – plant polyphenol containing foodstuffs and probiotics.
Professor Michael Gleeson leads a group of sport scientists at Loughborough University investigating the effects of intensive exercise on immune function and the efficacy of various nutritional supplements in boosting immune function and reducing infection risk in athletes.