Related Experiment Videos
Effects of fasting on endurance exercise
1Division of Kinesiology, University of Michigan, Ann Arbor.
Sports Medicine (Auckland, N.Z.)
|October 1, 1993
Summary
Fasting appears detrimental to human exercise endurance, despite some animal studies suggesting benefits. The exact reasons for reduced performance in fasted humans remain unclear, though exercise intensity and placebo effects may play a role.
Area of Science:
- Exercise Physiology
- Nutritional Science
Background:
- Early research indicates fasting negatively impacts physical and endurance performance in humans.
- Conflicting findings exist, with one rat study reporting enhanced endurance due to glycogen sparing from fasting.
Purpose of the Study:
- To explore the discrepancy in fasting's effect on exercise endurance between humans and rats.
- To identify potential factors influencing conflicting results on exercise performance during fasting.
Main Methods:
- Review of existing human and rat studies on fasting and exercise performance.
- Analysis of potential confounding variables such as glycogen sparing, exercise mode, fast duration, physiology, and training status.
Main Results:
- Most human studies show fasting impairs endurance performance.
- Discrepancies between human and rat responses could not be attributed to known physiological or methodological differences.
- Exercise intensity and potential placebo effects are proposed explanations for conflicting results.
Conclusions:
- Fasting generally reduces exercise endurance in humans, though the precise cause of earlier fatigue is still unclear.
- Despite reduced endurance, fasted individuals can maintain blood glucose homeostasis during exercise.