ABSTRACT
Athletes sometimes ask ‘I have a cold, should I still train?’ or ‘Why do I often come down with a cough or a cold after a period of heavy training?’ e answer is related to the function of the immune system and how it is affected by exercise. We will begin this chapter by reviewing the immune system in relation to exercise. e immune system is by nature a
molecular and cellular subject. is is because the main players are cells that can be identified by molecules, rather than organs such as the heart in the cardiovascular system. In fact it is often said that molecular biology is a major driving force behind immunology research, with a prime example being the ability to identify and clone the numerous cytokines involved in immune regulation. A recent example of molecular methods in immunology is seen in the awarding of one half of the 2011 Nobel Prize in Physiology or Medicine to Jules Hoffmann and Bruce Beutler. In 1996 Hoffmann found that when infected with bacteria or fungi, fruitflies with Toll gene mutations died because they were unable to mount an effective immune defence. Two years later, Bruce Beutler found that a gene in mice very similar to Toll, thus named the Toll-like receptor, was the receptor for lipopolysaccharide, an endotoxin secreted by bacteria. ese two discoveries were the starting point in identifying the way in which pathogens activate the innate immune system and are great examples of the importance of molecular techniques in immunology research.
