METABOLIC, ENDOCRINE, HEMODYNAMIC AND PULMONARY RESPONSES TO DIFFERENT TYPES OF EXERCISE IN INDIVIDUALS WITH NORMAL OR REDUCED LIVER-FUNCTION

The liver is central to the metabolic response to exercise but measure ments of effects of reduced liver function on the physiological adapta tion to exercise are scarce. We investigated metabolic, endocrine, pul monary and haemodynamic responses to exercise in 15 healthy untrained controls (Go) and in 30 subjects with reduced liver function (i.e. liv er cirrhosis, Ci). The following protocols were used: protocol I maxim al oxygen uptake (VO2max) and anaerobic threshold (AT), protocol 2 ste pwise increases in exercise intensity from 0 to 40% VO2max giving stea dy-stage conditions, protocol 3 Ih exercise at 20% VO2max. Muscle glyc ogen content was determined in 15 Ci. Spirometry was essentially norma l in Ci. Result: protocol I Ci had impaired VO2max and reduced AT (P < 0.05). Basal plasma concentrations of insulin, glucagon, growth hormo ne and adrenaline were increased in Ci (P < 0.05); cortisol was normal . During exercise, only glucagon remained different between groups. In protocol 2 Ci had decreased resting respiratory exchange ratio (RQ: p < 0.05) associated with increased plasma concentrations of free fatty acids and glycerol, They had disproportionately enhanced lipolysis an d Re, heart rate (+ 24%), ventilation (+ 28%), thermal effects of exer cise (+ 31%) and intrapulmonary shunt volume (+ 76%), which accounted for 11.7 (SD 3.0) or 7.4 (SD 0.9%) of cardiac output during exercise i n Ci and Co, respectively (P < 0.05 for all the differences reported). The metabolic effects of Ci were independent of the clinical and nutr itional state of the patients. In protocol 3 muscle glycogen content w as highly variable in Ci, but mean values were normal [16.9 (SD 8.9) m u mol . g(-1) wet mass]. Glycogen content positively correlated with r esting and exercise-induced RQ, but negatively correlated with the exe rcise-induced alterations in plasma glucose concentration. From these results eluded that with reduced liver function VO2max AT are reduced, but metabolic, pulmonary haemodynamic reponses per unit power output are enhanced. Muscle glycogen content would seem to contribute to the metabolic response, but its mobilization to be limited in individuals with reduced liver function.