Abstract

It is generally accepted that moderate amounts of exercise improve immune system functions and hence reduce the
risk of infection. However, there is strong evidence that athletes engaged in regular prolonged and/or intensive
training have a higher than “normal” incidence of minor infections, especially of the upper respiratory tract (URT,
e.g., common cold and influenza). This is particularly apparent in endurance athletes
such as cyclists, runners, swimmers, and triathletes, but any athletes with a high training load and/or suboptimal
recovery may be at increased risk. Such infections can compromise training and/or competition performance.