Speed- and Circuit-Based High-Intensity Interval Training on Recovery Oxygen Consumption
Question
Do speed-based and circuit-based HIIT sessions differ in exercise oxygen cost, recovery oxygen consumption, and estimated caloric expenditure in regular exercisers and sedentary adults?
Summary
In a randomized acute crossover comparison, speed interval training on a self-propelled treadmill burned more calories during the exercise bout than a bodyweight-style circuit, but recovery oxygen consumption over 30 minutes was similar. Sedentary participants reported discomfort with the self-propelled treadmill.
Methodology
- Young adult regular exercisers and sedentary participants from a university campus.
- 26 participants.
- Self-propelled treadmill running.
- Work intervals: 30 seconds.
- Recovery: 30 seconds active walking.
- Intensity: Target >=85% HRR; highest HRR 96.7 +/- 6.44%.
- 15 minutes including warm-up; recovery measured for 30 minutes.
- Single acute session.
- One session.
- Randomized acute crossover modality comparison
- Exercise VO2, Recovery VO2, and Caloric expenditure were tracked.
Outcomes
Exercise VO2
SIT elicited higher oxygen consumption during exercise than CT.
F=8.15, p=0.010.
Recovery VO2
Recovery oxygen consumption was similar between SIT and CT and between exercise-status groups.
Modality p=0.592; exercise status p=0.885.
Calories
SIT had higher during-exercise estimated calories, but post-exercise calories did not differ.
Exercise calories p=0.010; post-exercise no modality/group effects.
Insights
- A 10 x 30/30 bodyweight circuit may produce similar 30-minute recovery oxygen cost to speed intervals.
- Running speed intervals may increase in-session oxygen cost but can be less comfortable for sedentary users.
Limitations
- Acute-only study.
- Young campus sample.
- Calories estimated from VO2.
- Some participants could not complete or had unusable data.
Safety
- No adverse events or injuries were reported.
- PAR-Q screening, HR/RPE monitoring, familiarization, and qualified supervision were used; sedentary participants reported discomfort with the self-propelled treadmill.