The acute effects of low-intensity exercise on plasma lipids in endurance-trained and untrained young adults.
The acute effects of low-intensity exercise on plasma lipids were assessed in 22 healthy, normolipidaemic volunteers [mean age (SEM) 21.1 (0.2) years] of whom 11 were untrained and 11 endurance trained. Each subject walked for 2 h on a treadmill at a speed selected to elicit 30% [29.8 (3.9)%] of his or her maximal oxygen uptake. All subjects consumed a similar diet, i.e. 48% of energy from carbohydrate, for 2 days prior to the test. Pre-exercise, high-density lipoprotein (HDL) cholesterol concentration was higher in the trained group than in the untrained group [0.88 (0.06) mmol.l-1 vs 0.73 (0.09) mmol.l-1, P less than 0.05]. The walk elicited an increase in blood lactate concentration (P less than 0.01) but glucose homeostasis was well maintained by both groups. After 2 h of walking total cholesterol had increased by 13 (0.6)% (P less than 0.05). HDL cholesterol concentration increased by 17 (1.6)%, so that the ratio of total to HDL cholesterol was lower after the walk than pre-exercise (P less than 0.05). In the endurance-trained group HDL cholesterol concentration increased progressively, being 7.9 (2.4)% higher after 1 h and 19.7 (1.6)% higher after 2 h. A different response was evident in the untrained group where a rise after the 1st h [25.1 (2.3)%] was followed by a decrease towards pre-exercise values. These results show that one prolonged bout of low-intensity exercise modifies lipoprotein metabolism and hold out the interesting possibility that this response may differ in trained and untrained individuals.
Pay
H E
HE
Department of Physical Education and Sports Science, Loughborough University of Technology, England.
Hardman
A E
AE
Jones
G J
GJ
Hudson
A
A
D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D008076:Cholesterol, HDL / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007773:Lactates / Q000097:blood; D008055:Lipids / Q000097:blood*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D016138:Walking
D001786:Blood Glucose; D008076:Cholesterol, HDL; D007773:Lactates; D008055:Lipids