Repeated breathlessness experiences induced by hypercapnia: differential effects on intensity and unpleasantness.
BACKGROUND
The present study investigated the effect of repeated hypercapnic challenges on the sensory (intensity [I]) and affective (unpleasantness [U]) dimensions of breathlessness.


METHODS
Three subsequent rebreathing trials (Read, 1968) were administered to healthy men and women (n = 39). The I and U of breathlessness were rated every 20 s during the baseline, rebreathing, and recovery phases. Breathing behavior (fractional end-tidal CO(2) [Fetco(2)] and minute ventilation [Ve]) was monitored continuously. Intraindividual linear regression slopes for Fetco(2) and Ve] were calculated and standardized, separately for both rating dimensions.


RESULTS
Both the absolute magnitude and the slope of the I of breathlessness were higher compared to U (p < 0.05). Across-trial habituation of the peak I and U of breathlessness occurred in both genders (p < 0.001), but habituation was larger for the U than for the I (p = 0.05).


CONCLUSIONS
The findings show that the sensory and affective dimensions of breathlessness can meaningfully be distinguished during hypercapnic challenges and that repeated exposures have different effects on both dimensions.
Wan
Li
L
Department of Psychology, University of Leuven, Leuven, Belgium.
Van Diest
Ilse
I
Department of Psychology, University of Leuven, Leuven, Belgium.
De Peuter
Steven
S
Department of Psychology, University of Leuven, Leuven, Belgium.
Bogaerts
Katleen
K
Department of Psychology, University of Leuven, Leuven, Belgium.
Van den Bergh
Omer
O
Department of Psychology, University of Leuven, Leuven, Belgium. Electronic address: omer.vandenbergh@psy.kuleuven.be.
D000293:Adolescent; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood*; D004417:Dyspnea / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000150:complications / Q000503:physiopathology / Q000523:psychology*; D055809:Illness Behavior; D001239:Inhalation / Q000502:physiology; D008297:Male; D012016:Reference Values; D018570:Risk Assessment; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D012684:Sensory Thresholds; D012737:Sex Factors; D055815:Young Adult
D002245:Carbon Dioxide