Metabolic effects of exercise in patients with type IV hyperlipoproteinemia

Abstract

Metabolic responses to 30 minutes of submaximal exercise were investigated in 11 healthy control subjects and 6 patients with type IV hyperlipoproteinemia (endogenous or essential hypertriglyceridemia). All subjects were male and ranged in age from 35 to 55 years. Before exercise they fasted overnight for at least 12 hours. The relative work performed, judged by the levels in heart rate and cardiac output on exercise, was comparable in the two groups, and the effects of exercise were qualitatively similar. Plasma glucose and triglyceride levels showed little change. Plasma concentration of cholesterol increased at the end of exercise by approximately 13 percent above control values compared to a concomitant increase in hematocrit of 3 percent. Plasma free fatty acid levels fell as exercise started and then returned to normal valves at the end of the 30 minutes of exercise; they then increased markedly after exercise but returned subsequently to control levels after 45 minutes. In response to muscular exercise, therefore, both control subjects and patients with type IV hyperlipoproteinemia significantly increase plasma cholesterol concentration. Subjects with hyperlipoproteinemia appear to mobilize free fatty acids in a normal manner for energy purposes, and the excess release of free fatty acids during exercise is apparently not derived from the abundantly circulating triglycerides; the latter were not altered by submaximal exercise.