Related Experiment Videos
Postexercise energy expenditure and substrate oxidation in young women resulting from exercise bouts of different
J F Phelain1, E Reinke, M A Harris
1Department of Food Science and Human Nutrition, Colorado State University, Ft. Collins 80523, USA.
Objective:
The effects of low and high intensity exercise, of similar energy output, on exercise and post-exercise energy expenditure and substrate oxidation were studied in eight active, eumenorrheic females (aged 22 to 31).
Methods:
Continuous indirect calorimetry was performed during cycle ergometry exercise and for 3 hours following each of the following three protocols administered in random order: 1) low intensity exercise (LIE: 500 calories 50% VO2 max), 2) high intensity exercise (HIE: 500 calories 75% VO2 max), and 3) control condition (C) of quiet sitting for 1 hour, rather than exercise. Excess postexercise oxygen consumption (EPOC), energy expenditure and total fat and carbohydrate oxidation for the entire exercise/control plus 3-hour recovery period were determined by indirect calorimetry.
Results:
Mean EPOC for the 3-hour post-exercise period for HIE (9.0 +/- 1.7 L, 41 kcals) was significantly greater than EPOC for low intensity exercise (4.8 +/- 1.6 L, 22 kcals). Oxygen consumption (VO2) following HIE, but not LIE remained elevated at the end of the 3-hour post-exercise period. Total carbohydrate oxidation (exercise plus postexercise period) was significantly higher for HIE (116 +/- 8.6 g) compared to LIE (85.0 +/- 5.2 g). Total fat oxidation was lower for HIE (27.7 +/- 3.3 g) compared to LIE (36.9 +/- 3.0 g), but this difference did not reach statistical significance (p = 0.07). At the end of the 3-hour recovery period, the rate of fat oxidation was higher following HIE compared to LIE.
Conclusion:
These data indicate that the recovery period should also be considered when determining the impact of different exercise intensities on total energy expenditure and fat and carbohydrate utilization in women.