Studies in asymptomatic primary hyperlipidaemia, III. Physical working capacity.

Abstract

One-hundred-and-sixty male and 123 female subjects with asymptomatic primary hyperlipidaemia (HLP) selected from a health control centre have been studied with a heart rate (HR) controlled exercise test. Ther serum cholesterol and/or TG at screening were above 350 mg/100 ml and 3.5 mmol/l, respectively. As a reference group 49 male and 60 female age-matched subjects from the same centre with serum cholesterol below 300 mg/100 ml and TG below 2.00 mmol/l were investigated using the same technique. Quantitative lipoprotein (LP) analyses and typing were performed on all HLP and control subjects. The subjects were divided into two age groups, 36-50 and above 50 years of age. Men with all types of HLP had lower working capacity, expressed in W170 or W150, than controls, most pronounced in the younger age group. Younger women with type II A had lower working capacity than their controls. After correction for variation in body weight and age there remained a significantly lower W150, in male types II A (11%) and IV (21%) and female type II A (11%). There was no difference in systolic BP during exercise between controls and HLP. The total exercise time and final HR did not differ in control and HLP subjects. Dynamic spirometry was performed im 102 of the male subjects and a significantly lower vital capacity was found in HLP subjects compared with controls after correction for variation in age, weight and height. No differences were found in the maximal flow values. The observed differences in working capacity between controls and HLP subjects are explained by a difference in stroke volume. The lower stroke volumes in male types II A and IV and female type II A could be explained by a lower degree of physical fitness, by a common genetic factor resulting in HLP and decreased stroke volume or by a less effective myocardial function in HLP subjects.