A strong immune system is important especially for athletes because if they get sick it results in a reduced training load/intensity and thus reduced performance. Therefore athletes need to ensure adequate nutrition, rest and sleep is maintained to reduce both injury...
Endurance sports typically refers to running, cycling or swimming events lasting an hour or longer. Or all three combined as in triathlon events which has become very popular in the 40 plus age group. Rowing and Cross country skiing are other examples of endurance...