Acute Physiological Responses to Moderate-Intensity Continuous, High-Intensity Interval, and Variable-Intensity...

Area of Science:

• Exercise Physiology
• Sports Science
• Human Performance

Background:

• Understanding the acute physiological and perceptual responses to different exercise intensities and durations is crucial for optimizing training protocols.
• Moderate-intensity continuous exercise (MICE), variable-intensity intermittent exercise (VIIE), and high-intensity interval exercise (HIIE) represent distinct training modalities with varying physiological demands.
• Research comparing these protocols, matched for total work output, can elucidate their unique effects on the human body.

Purpose of the Study:

• To compare the acute physiological and perceptual responses to MICE, VIIE, and HIIE protocols in healthy adults.
• To analyze oxygen consumption, time spent in moderate and vigorous-intensity zones, affective responses, and post-exercise enjoyment across the three exercise conditions.
• To determine if VIIE serves as a practical alternative to established MICE and HIIE protocols.

Main Methods:

• A randomized crossover design involving three experimental trials: MICE (40% peak work rate), VIIE (intermittent bursts at varying intensities), and HIIE (2-minute intervals at 70% peak work rate).
• All protocols were matched for total work output.
• Physiological measures included oxygen consumption during work intervals, time in moderate and vigorous intensity zones. Perceptual measures included affective response and post-exercise enjoyment (PACES).

Main Results:

• Oxygen consumption during work intervals was higher in VIIE than MICE, but lower than HIIE.
• VIIE and HIIE demonstrated similar durations within the vigorous-intensity zone, significantly exceeding MICE.
• Time spent in the moderate-intensity zone was greatest in MICE, followed by VIIE, and lowest in HIIE. Affective responses were similar across all trials, while post-exercise enjoyment was higher in VIIE compared to HIIE, but not significantly different from MICE.

Conclusions:

• The variable-intensity intermittent exercise (VIIE) protocol elicits distinct physiological responses compared to MICE and HIIE.
• VIIE may be a suitable alternative to HIIE and MICE, offering comparable post-exercise enjoyment.
• Further research can explore the long-term adaptations and adherence rates associated with VIIE protocols.