Acute Cardiopulmonary and Metabolic Responses to High-Intensity Interval Training Protocols Using 60 s of Work and 60...

Area of Science:

• Exercise Physiology
• Sports Science
• Cardiopulmonary Function

Background:

• Low-volume, high-intensity interval training (HIIT) with 60-second work/60-second recovery (60s/60s) promotes beneficial adaptations.
• Limited data exists on the acute physiological responses during individual HIIT sessions.

Purpose of the Study:

• To investigate the acute physiological responses to 60s/60s x 10 HIIT protocols with varied work and recovery intensities.
• To compare the effects of different intensity combinations on cardiopulmonary and metabolic markers.

Main Methods:

• Eleven healthy adults completed four HIIT trials with varying peak power output (PPO) intensities: 80% PPO/0% PPO (80/0), 80% PPO/50% PPO (80/50), 100% PPO/0% PPO (100/0), and 100% PPO/50% PPO (100/50).
• Physiological responses including oxygen consumption (V[Combining Dot Above]O2peak), heart rate (HRpeak), rating of perceived exertion (RPE), and blood lactate were measured.

Main Results:

• The 100% PPO/50% PPO (100/50) protocol resulted in significantly higher peak, average, and nadir %V[Combining Dot Above]O2peak compared to other protocols.
• Most protocols elicited %V[Combining Dot Above]O2peak and %HRpeak values within recommended ranges for improving cardiopulmonary function.
• The 80/50 protocol showed a significantly higher average %V[Combining Dot Above]O2peak (approximately 9.3% absolute) than the 100/0 protocol, despite similar HR, RPE, and blood lactate levels.

Conclusions:

• The 100/50 HIIT protocol induces the greatest acute cardiopulmonary stress.
• Protocols like 80/0, 80/50, and 100/0 are suitable for individuals with low to moderate cardiopulmonary fitness.
• Understanding acute responses informs the selection of appropriate HIIT protocols for different fitness levels.