Subjective Estimates of Exercise Ability: Comparison to Objective Measurements

Area of Science:

• Pediatric Exercise Physiology
• Clinical Assessment
• Cardiopulmonary Function

Background:

• Physicians frequently use subjective patient-reported exercise ability to gauge health status and treatment effectiveness.
• The clinical utility of these subjective assessments remains poorly validated in pediatric populations.

Purpose of the Study:

• To compare subjective patient estimates of exercise ability with objective measurements obtained via cardiopulmonary exercise testing.
• To evaluate the reliability of subjective exercise capacity assessments in children and adolescents.

Main Methods:

• A standardized questionnaire was administered to 211 patients (mean age 13.9 years) to gather subjective exercise ability data.
• Objective exercise capacity was measured using maximal oxygen consumption (VO2 max) via cardiopulmonary exercise testing.
• Correlation and agreement analyses were performed between questionnaire responses and VO2 max values.

Main Results:

• Subjective exercise ability estimates showed a correlation with measured maximal oxygen consumption (VO2 max).
• Patients perceived as below average fitness had a VO2 max of 21±6 ml/kg/min, average fitness 26±8 ml/kg/min, and above average 30±7 ml/kg/min.
• Subjective estimates were unreliable, with 67% overestimating and 3% underestimating actual exercise ability, and only 30% agreement.

Conclusions:

• Subjective patient estimates of exercise ability are unreliable for assessing individual functional status.
• Objective cardiopulmonary exercise testing provides a more accurate measure of exercise capacity.
• While unreliable for individual assessment, subjective estimates may offer general insights into exercise capabilities within large population studies.