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Acute plasma volume expansion: effect on metabolism during submaximal exercise
M J Watt1, M A Febbraio, A P Garnham
1School of Health Sciences, Deakin University, Burwood, Victoria 3125, Australia.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|September 14, 1999
Summary
Acute plasma volume expansion (PVE) does not alter substrate metabolism during submaximal exercise in untrained men. Exercise performance and substrate utilization remain unchanged despite increased blood volume.
Area of Science:
- Exercise Physiology
- Sports Science
- Metabolic Research
Background:
- Understanding substrate utilization during exercise is crucial for optimizing athletic performance.
- Acute plasma volume expansion (PVE) is a potential ergogenic aid, but its effects on substrate metabolism require clarification.
Purpose of the Study:
- To investigate the impact of acute PVE on substrate selection during sustained submaximal exercise.
- To determine if increased plasma volume influences carbohydrate and fat oxidation during cycling.
Main Methods:
- Seven untrained men performed 40-minute cycling bouts at 72% VO2 peak.
- Plasma volume was expanded by 12% using Haemaccel in one trial; a control trial had no expansion.
- Muscle biopsies, gas exchange, and blood samples were collected pre- and post-exercise.
Main Results:
- No significant differences were found in oxygen uptake (VO2), heart rate, or respiratory exchange ratio between trials.
- Blood glucose, lactate, and muscle glycogen concentrations remained unaffected by PVE.
- Total carbohydrate oxidation was similar in both the control (108g) and PVE (105g) trials.
Conclusions:
- Acute hypervolemia does not alter substrate metabolism during submaximal exercise in untrained individuals.
- Plasma volume expansion does not appear to influence fuel selection or exercise capacity in this context.