Respiratory and Perceptual Responses to High-Intensity Interval Exercise in Obese Adults.

Area of Science:

• Exercise Physiology
• Obesity Research
• Respiratory Medicine

Background:

• High-intensity interval exercise (HIIE) is a popular alternative to continuous exercise (CE).
• The tolerability of HIIE in obese adults is not well understood, particularly regarding respiratory responses.
• Previous studies have not examined ventilatory constraints and dyspnea during HIIE in this population.

Purpose of the Study:

• To compare the respiratory and perceptual responses to HIIE versus CE in nonobese and obese adults.
• To investigate the impact of HIIE on ventilatory constraints and dyspnea in obese individuals.
• To assess the relative tolerability of different exercise intensities and types in obese adults.

Main Methods:

• Ten nonobese and ten obese adults participated.
• Participants underwent HIIE (8 intervals x 30s at 80% max work rate) and two 6-min CE sessions (below and above ventilatory threshold).
• Respiratory measures (e.g., expiratory flow limitation, dynamic hyperinflation) and perceptual responses (e.g., breathlessness, unpleasantness) were assessed.

Main Results:

• HIIE represented a higher relative intensity for obese participants (68.8% vs 58.9% maximal oxygen uptake).
• Expiratory flow limitation and/or dynamic hyperinflation occurred in 50% of obese participants during HIIE, but none of the nonobese.
• Obese participants reported significantly higher ratings of perceived breathlessness and unpleasantness during HIIE compared to nonobese individuals and compared to CE.

Conclusions:

• HIIE, when prescribed at a similar relative work rate, imposes greater ventilatory constraints and dyspnea in obese adults.
• Continuous exercise may be a more tolerable option for obese adults compared to HIIE.
• These findings highlight the importance of considering individual ventilatory responses when prescribing exercise for obese populations.