How to regulate the acute physiological response to "aerobic" high-intensity interval exercise

Area of Science:

• Exercise Physiology
• Sports Science
• Cardiorespiratory Fitness

Background:

• Acute physiological responses during high-intensity interval exercise (HIIE) are not well understood.
• Regulation and predictability of these responses require further investigation.

Purpose of the Study:

• To compare the acute metabolic and cardiorespiratory responses between long and short HIIE and continuous exercise (CE).
• To investigate the regulation and predictability of these physiological responses.

Main Methods:

• Six healthy, well-trained students underwent maximal incremental exercise tests.
• Participants performed 28-minute sessions of long HIIE, short HIIE, and CE, matched for mean workload.
• Metabolic and cardiorespiratory parameters, including lactate levels and heart rate, were measured.

Main Results:

• Short HIIE demonstrated significantly lower mean lactate, peak lactate, and peak heart rate compared to long HIIE.
• No significant differences were observed between short HIIE and CE in measured parameters, despite higher peak workloads in short HIIE.
• Acute metabolic and cardiorespiratory demand in short HIIE was lower than long HIIE and controllable via mean workload.

Conclusions:

• Short HIIE induces a lower acute physiological demand than long HIIE, comparable to CE.
• The physiological response to short HIIE is predictable and regulable by mean workload.
• Prescribing exercise intensity using objective markers like lactate turn points is recommended for both continuous and intermittent exercise.