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Studies in asymptomatic primary hyperlipidaemia, III. Physical working capacity
Insights
Individuals with hyperlipidaemia (HLP) exhibit reduced exercise working capacity and vital lung capacity compared to healthy controls. These differences may stem from lower stroke volume, potentially due to decreased physical fitness or myocardial function.
Area of Science:
- Cardiology
- Exercise Physiology
- Lipid Metabolism
Background:
- Hyperlipidaemia (HLP) is a condition characterized by elevated serum lipid levels.
- Asymptomatic primary HLP affects a significant portion of the population.
- The impact of HLP on cardiovascular fitness and pulmonary function requires further investigation.
Purpose of the Study:
- To assess the exercise working capacity and pulmonary function in individuals with asymptomatic primary hyperlipidaemia.
- To compare these parameters between HLP patients and age-matched healthy controls.
- To explore potential underlying mechanisms for observed differences.
Main Methods:
- 160 male and 123 female subjects with primary HLP and 49 male and 60 female controls underwent heart rate-controlled exercise testing.
- Quantitative lipoprotein analyses were performed.
- Dynamic spirometry was conducted on 102 male subjects.
Main Results:
- Men with all types of HLP showed lower working capacity (W170/W150) than controls, particularly in younger age groups.
- Younger women with type II A HLP also had lower working capacity.
- HLP subjects exhibited significantly lower vital capacity after adjusting for covariates, with no differences in maximal flow values.
Conclusions:
- Asymptomatic primary hyperlipidaemia is associated with reduced exercise working capacity and vital lung capacity.
- Differences in stroke volume, potentially linked to physical fitness, genetics, or myocardial function, may explain these findings.
- Further research is warranted to elucidate the precise mechanisms and clinical implications.
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.