Study objectives: We tested the hypothesis that
descriptors of breathlessness represent distinct and separable
cognitive constructs, and predicted that the use of descriptors of
breathlessness by healthy individuals is the same as their use by
patients with cardiopulmonary disease.
analyses obtained in healthy individuals were compared with those
obtained previously in patients who complained of breathing discomfort.
In addition, we used multidimensional scaling (MDS) techniques to
analyze relationships among descriptors in healthy individuals.
Setting: Public university.
The participants were 100 healthy individuals (48 men and 52 women)
ranging in age between 18 and 65 years (mean, 27.9 ± 11.7
Measurements and results: Participants judged
the dissimilarity among pairs of 15 descriptors of breathlessness that
were used previously to examine the experience of dyspnea in patients
who complained of breathing discomfort. Cluster analysis solutions
obtained in the healthy individuals were virtually identical to those
obtained previously in patients. Three dimensions (attributes) of
breathing discomfort were uncovered with MDS: “Depth and frequency of
breathing,” “Perceived need, or urge, to breathe,” and“
Difficulty breathing and phase of respiration.” The results did
not depend on age, sex, levels of education, or the presence of
uncomfortable awareness of breathing with activities.
Conclusions: The relations among descriptors of
breathlessness obtained in healthy individuals support the contention
that the association of different clusters with different disease
states reflects distinct and separable cognitive constructs that are
not simply dependent on the presence of an underlying pathophysiology
or on a specific disease condition. Our results in healthy individuals
also suggest that distinct qualities of breathlessness relate to
different physiologic mechanisms underlying respiratory