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Acute effects of exercise on plasma lipids, noradrenaline levels and plasma volume
H Krum1, E L Conway, L G Howes
1Department of Clinical Pharmacology and Therapeutics, Austin Hospital, Heidelberg, Victoria, Australia.
Insights
Vigorous exercise temporarily elevates total cholesterol, HDL-C, and LDL-C due to plasma volume changes, not altered LDL:HDL ratios. These findings suggest plasma volume shifts may link stress to higher cholesterol.
Area of Science:
- Exercise Physiology
- Clinical Biochemistry
Background:
- Understanding the acute effects of exercise on lipid profiles is crucial for cardiovascular health.
- Previous research has explored exercise's impact on various physiological markers, but the immediate post-exercise cholesterol dynamics require further clarification.
Purpose of the Study:
- To investigate the acute changes in total plasma cholesterol, HDL-C, and LDL-C following vigorous exercise.
- To determine if exercise-induced alterations in plasma volume influence these lipid parameters.
- To examine the relationship between exercise, plasma volume, and potential mechanisms linking environmental factors like stress to cholesterol levels.
Main Methods:
- Nine healthy volunteers underwent 5 minutes of vigorous bicycle exercise.
- Blood samples were collected pre-exercise and at intervals up to 1 hour post-exercise.
- Measurements included total plasma cholesterol, HDL-C, LDL-C, noradrenaline, haematocrit, haemoglobin, and heart rate.
Main Results:
- Heart rate and noradrenaline significantly increased immediately post-exercise, returning to baseline within 60 minutes.
- Total plasma cholesterol, HDL-C, and LDL-C showed significant increases (24%, 27.7%, and 20.2% respectively) immediately post-exercise, normalizing by 60 minutes.
- LDL:HDL ratios remained unchanged, and observed lipid changes were attributed to exercise-induced plasma volume reduction.
Conclusions:
- Vigorous exercise causes transient increases in total cholesterol, HDL-C, and LDL-C, primarily driven by acute changes in plasma volume.
- The LDL:HDL ratio is not significantly altered by acute vigorous exercise.
- Plasma volume fluctuations following exercise may represent a physiological mechanism contributing to the association between stressors and elevated plasma cholesterol.
Abstract:
1. Total plasma cholesterol, high-density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), noradrenaline, haematocrit, haemoglobin and heart rate were measured in blood sampled from an antecubital vein in nine volunteers after 1 min standing and at intervals up to 1 h following 5 min of vigorous bicycle exercise. 2. Heart rates and plasma noradrenaline levels rose substantially immediately following exercise and gradually returned toward baseline levels 60 min post-exercise. 3. Total plasma cholesterol levels rose by 24% immediately post-exercise and slowly returned to baseline levels 60 min post-exercise. Similar changes were observed for LDL-C (20.2%) and HDL-C (27.7%). As a result, LDL:HDL ratios did not alter. 4. These changes in total plasma cholesterol, HDL-C and LDL-C were explained by changes in plasma volume that occurred as a consequence of vigorous exercise. 5. Changes in plasma volume may be a mechanism by which some environmental factors such as stress are associated with elevated plasma cholesterol levels.