An enduring hypothesis in exercise physiology holds that a limiting cardiorespiratory function determines maximal exercise performance as a result of specific metabolic changes in the exercising skeletal muscle, so-called peripheral fatigue. The origins of this classical hypothesis can be traced to work undertaken by Nobel Laureate A. V. Hill and his colleagues in London between 1923 and 1925. According to their classical model, peripheral fatigue occurs only after the onset of heart @entity177 . Thus, correctly interpreted, the Hill hypothesis predicts that it is the heart, not the skeletal muscle, that is at risk of anaerobiosis or ischaemia during maximal exercise. To prevent @entity296 during maximal exercise, Hill proposed the existence of a 'governor' in either the heart or brain to limit heart work when @entity296 developed. Cardiorespiratory function during maximal exercise at different altitudes or at different @entity26 fractions of inspired air provides a definitive test for the presence of a governor and its function. If skeletal muscle anaerobiosis is the protected variable then, under conditions in which arterial @entity26 content is reduced, maximal exercise should terminate with peak cardiovascular function to ensure maximum delivery of @entity26 to the active muscle. In contrast, if the function of the heart or some other @entity26 -sensitive organ is to be protected, then peak cardiovascular function will be higher during @entity871 and reduced during @entity519 compared with normoxia. This paper reviews the evidence that peak cardiovascular function is reduced during maximal exercise in both acute and chronic @entity519 with no evidence for any primary alterations in myocardial function. Since peak skeletal muscle electromyographic activity is also reduced during @entity519 , these data support a model in which a central, neural governor constrains the cardiac output by regulating the mass of skeletal muscle that can be activated during maximal exercise in both acute and chronic @entity519 .

Evidence that a central governor regulates exercise performance during acute @entity519 and XXXX .

@entity296 :: ('MESH:D009202', 'Disease') :: ['myocardial ischaemia', 'myocardial damage'] @entity871 :: ('MESH:D018496', 'Disease') :: ['hyperoxia'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity177 :: ('MESH:D051437', 'Disease') :: ['fatigue or failure'] @entity519 :: ('MESH:D000860', 'Disease') :: ['hypoxia']
@entity871 :: (MESH:D018496,Disease) :: ['hyperoxia']
