Articles Long Distance Racing

Immune System and Training

The number one question in sport, especially in competitive sport is whether training makes an individual more resistant to infections or does training strengthen ones immune system. The answer, like in most disciplines is that it depends on the type, intensity, length of the activity and the amount of rest the athlete has.

Research has shown

1. That immune system responses changes from an increased level of activity but decreases when the activity is carried out for an extended period of time(>160mins)
2. That immune system mechanisms such as circulating lymphocytes, circulating leukocytes, epinephrine and norepinephrine increases to its peak after 40mins of exercise but slowly decreases after exercises are carried out for >160mins
3. That the most optimum duration for immune strengthening exercise is between 40-45mins, far shorter then the length of our average training session.
4. Immune system decreases 10% for every hour of sleep below 7hrs and 30mins (e.g. immune system functions at 90% of its maximum potential after 6hrs and 30mins of sleep and only 70% after 4hrs and 30mins of sleep). Hence, people who lack rest usually put themselves at a greater risk of falling ill, especially if they engage in strenuous physical activity.
5. Exercise can directly stimulate immune system function, stimulate sympathetic nervous system, alter the amount of circulating hormones in the body, increase body temperature (key to changing levels of immune mechanisms) and induce cellular damage which can impair or reduce level of immunity temporarily.

All in all it must be said that the body continually adapts to the stress it faces. Physical activity definitely contributes to strengthened immune system and increased immune system function if done in an appropriate fashion. To best achieve this, training must be done with proper warm up and warm down sections, it must also be done in an environment where the pollution levels (Air quality) is at an acceptable level (cycling through town during the day or running along a busy road is a “no go” for training), finally, the athlete should have enough rest prior and post training. It is only when all these factors are properly adhered to can one achieved not only good fitness but also good bill of health.