When to Best Assess Breathlessness Abnormality During Incremental Cardiopulmonary Cycle Exercise Testing

Area of Science:

• Pulmonary Medicine
• Exercise Physiology
• Clinical Diagnostics

Background:

• Breathlessness on exertion is a prevalent, distressing symptom limiting daily activities.
• Incremental cardiopulmonary exercise testing (CPET) quantifies breathlessness using normative data.
• Accurate assessment of breathlessness is crucial for diagnosis and management.

Purpose of the Study:

• To determine if breathlessness abnormalities are best detected at peak exercise (symptom limitation) versus submaximal intensities.
• To compare the sensitivity of breathlessness assessment at different exercise levels during CPET.

Main Methods:

• Analysis of 1,161 participants (≥40 years) from the Canadian Cohort Obstructive Lung Disease (CanCOLD) study undergoing symptom-limited incremental cycle CPET.
• Breathlessness intensity ratings (Borg scale) were converted to probabilities of being normal relative to power output, oxygen uptake, and ventilation.
• Abnormal breathlessness defined as a probability of being normal < 0.05.

Main Results:

• Abnormally high breathlessness was present in 16-23% of participants at peak exercise.
• Among those with abnormal peak exercise breathlessness, 55-60% had normal breathlessness at submaximal levels.
• High agreement (93-97%) was observed between peak exercise and serial submaximal breathlessness ratings in those without abnormal peak exercise breathlessness.

Conclusions:

• Abnormal breathlessness is most effectively uncovered and should be assessed at peak exercise during symptom-limited incremental CPET.
• These findings support peak exercise assessment for breathlessness in research and clinical settings.
• Assessment at peak exercise improves the diagnostic utility of CPET for breathlessness.