A large number of studies have failed to show whether exercise-induced perturbations
in immune function are associated with the incidence of infection. „Sports immunology”,
examining the interaction of physical, psychological and environmental stress on immunity,
is emerging as a sub-discipline of sports medicine. A series of studies by our research
team has profiled the immune responses of elite swimmers during training. Serum immunoglobulin
and lgC subclass levels were lower in swimmers than controls. Suppression of mucosal
immune parameters has been associated with the risk of upper respiratory tract infection.
Swimmers with a lower pre-season salivary lgA and/or lower pre-exercise salivary lgA
level were more likely to contract an URTI during a 7-month training period. In a
shorter 12-week study, infected swimmers had a mean salivary lgM concentration that
dropped more sharply after a single training session. Significant declines in natural
killer cell count and neutrophil oxidative activity were not associated with URTI.
Despite systemic and mucosal immunosuppression a cohort of swimmers were also able
to mount an antibody response to pneumococcal vaccine eguivalent to that of sedentary
individuals. Observations of chronic suppression of aspects of host defence and the
significant relationship between changes in mucosal immune parameters and URTI, provide
a framework for assessment of the immune status of athletes. The underlying causes
of upper respiratory tract distress symptoms may be infective, inflammatory or allergic
in origin: a differential diagnosis has implications for treatment and management.
Key words
Elite athletes - upper respiratory tract infection - immunoglobulins - exercise -
training - host defence
