Acute infections are associated with multiple host responses that are triggered by
cytokines and correlated to fever, malaise and anorexia. The purpose of this systemic
acute phase host reaction („the acute phase response”) is to mobilize nutrients for
the increased needs of the activated immune system, as well as for energy production
and tissue repair. Important effects include wasting of striated muscle, degradation
of performance-related metabolic enzymes and, concomitantly, deteriorated central
circulatory function. These effects result in decreased muscle and aerobic performance,
the full recovery of which may require several weeks to months following week-long
febrile infections. Also during early infection and fever, prior to the development
of muscle wasting, performance is compromised by other mechanisms. Strenuous exercise
may be hazardous during ongoing infection and fever and should always be avoided.
In infection, muscle wasting seems to be less pronounced in the conditioned (trained)
host than in the unconditioned host. Acute myocarditis most often has a viral etiology
but bacteria and their toxins may also be the cause. Furthermore, slow-growing bacteria,
previously difficult to diagnose, have emerged as potential "new" causes of subacute
to chronic myocarditis. Since myocarditis may or may not be associated with fever,
malaise, or catarrhal symtoms, athletes should be taught the symptoms suggestive of
myocarditis. Whenever myocarditis is suspected exercise should be avoided.
Key words
Infection - metabolism - muscle - acute phase response - performance - physical training
(conditioning) - myocarditis - sudden unexpected death (SUD)
