Are self-reports of breathing effort and breathing distress stable and valid measures among persons with asthma, persons with COPD, and healthy persons?

BACKGROUND: Breathing is a subjective experience that includes physical sensations, such as effort to breathe, and an affective element, such as breathing distress. OBJECTIVE: The overall purpose of this investigation was to evaluate whether measurement of the physical sensations (breathing effort) and affective response to these sensations of breathing (breathing distress) are consistent and valid. DESIGN: A longitudinal repeated measures design was used to evaluate a 2-week daily breathing with a sub-sample (n = 43) who also recorded their daily breathing during 4 weeks. SUBJECTS: Age-matched, stable subjects (n = 92) with an average age of 62 were evaluated. The sample consisted of 32 subjects with chronic obstructive pulmonary disease, 27 subjects with asthma, and 33 healthy subjects. MEASURES: Visual Analogue Scales for breathing effort (VAS-E) and breathing distress (VAS-D) were scored daily. RESULTS: The VAS-E and VAS-D mean, highest, and lowest scores were found to be stable over time in the sub-sample and a significant difference (F = 2.56, P < .05) between VAS-E and VAS-D was found. Differences were found in mean and highest VAS-E and VAS-D by group, with the COPD group reporting the highest values. CONCLUSIONS: This investigation provided initial evidence of the stability and validity of daily VAS-E and VAS-D measures and preliminary support for the use of daily VAS logs to evaluate differences in breathing effort and breathing distress.