The effect of moderate- and high-intensity interval training on substrate oxidation and nutrient preferences in obese men

Background

This study compared the influence of 12 sessions of moderate- and high-intensity interval training on substrate oxidation and nutrient preferences.

Methods

Ten obese men participated in cross-over 4-week moderate- (MIIT) and high- (HIIT) intensity interval cycling. MIIT consisted of 5-min stages at ±20% of mechanical work at 45 %VO_2peak, and HIIT consisted of 30-sec work at 90 %VO_2peak and 30-sec rests for 30-45 min. The assessments included a constant-load test consisted of 5-min rest, 45-min cycling at 45 %VO_2peak followed by 60-min recovery. Intermittent measures of gas exchange using indirect calorimetry were undertaken, and ad libitum meal was provided after the test. Consent to publish the results was obtained from all participants.

Results

Changes in fat oxidation were +19% at rest, +96% during exercise and +59% during recovery in MIIT, and were -7% at rest, +43% during exercise and -13% during recovery in HIIT. Changes in CHO oxidation were +6% at rest, -13% during exercise and -2% during recovery in MIIT, and were +46% at rest, -7% during exercise and +32% during recovery in HIIT. The amount of meal, fat and CHO eaten decreased by 24, 16 and 13% respectively after HIIT, and increased by 3, 38 and 14% respectively after MIIT. The intervention explained 12.4% of the changes in fat intake (p = 0.07). The interaction of fat oxidation*intervention did not significantly explain the change in fat eaten (p>0.05).

Conclusion

The change in fat oxidation did not explain the change in fat eaten after interval training.