Special feature for the Olympics: effects of exercise on the immune system: exercise effects on mucosal immunity

The adverse effects of elite competition on health and well-being

It is often assumed that participation in sport will produce only an array of health benefits. The adverse consequences of sport participation, particularly at the elite level, are rarely explored. Evidence continues to accumulate of a variety of unfortunate consequences that may accompany elite sport participation. Sport involvement may exacerbate pre-existing health problems, cause injury or even death. The sport environment may be hazardous in a variety of physical, emotional, and social ways. The common training and competition practices of certain sport cultures may themselves be harmful. Athletes may sacrifice health, home, education and normal social development in the pursuit of sport "success." Sport medicine professionals and sport scientists have particular opportunities and responsibilities to act as an athlete's advocate--and to protect their health and well being.

Epstein-Barr virus reactivation and upper-respiratory illness in elite swimmers

PURPOSE

The aim of this study was to investigate the relationships between latent viral shedding of Epstein-Barr virus (EBV) in saliva, upper-respiratory illness, and mucosal immune suppression in a cohort of highly trained swimmers undertaking intensive training.

METHODS

Saliva was collected before selected training sessions from 14 elite male swimmers during a 30-d period of intensive training. Prior infection with EBV was determined by EBV antibody serology. Salivary IgA concentrations were measured by enzyme linked immunosorbent assay (ELISA), and EBV viral shedding (EBV-DNA) was detected by polymerase chain reaction (PCR). Symptoms of upper-respiratory illness were recorded daily.

RESULTS

Eleven swimmers (79%) were seropositive for prior EBV infection. Seven EBV seropositive swimmers (64%) had EBV-DNA detected during the study period. Upper-respiratory symptoms (URS) were reported in six of seven swimmers in whom EBV-DNA was detected and in three of four swimmers with no EBV-DNA detection. No URS were reported in the EBV seronegative swimmers. There was a statistically significant relationship between EBV serology status and URS (P = 0.027). EBV-DNA was detected in saliva before the appearance of URS. Salivary IgA levels were significantly lower immediately before the URS (P = 0.01) compared with subsequent peak IgA levels and declined to pre-URS levels on average 11 d after the first appearance of URS.

CONCLUSIONS

The time course of appearance of EBV-DNA in relation to URS suggests latent viral EBV shedding may be a contributing factor in the URS. The low levels of salivary IgA detected before the URS indicated transient mucosal immune suppression in the study cohort. The viral shedding may alternatively be a reflection of the altered immune control mechanisms that occur in response to intensive exercise and unrelated to the URS.

Special feature for the Olympics: effects of exercise on the immune system. Overview: exercise immunology

The review articles in this special feature reflect the current status of knowledge in the field of exercise immunology, with a focus on how exercise affects the human immune system and the health implications for resistance to infections and neoplastic diseases. In an Olympic year, the emphasis of exercise immunology research tends to be on elite athletes and the prevention of infections in the quest for optimum performance. However, research presented in this issue also covers recreational athletes, as well as highlighting the benefits of exercise for our ageing population.