Dyspnea in obese healthy men.
OBJECTIVE
To determine whether obese, apparently healthy individuals experience dyspnea at rest and, if so, whether their pulmonary function test (PFT) profile and maximal respiratory pressures are different from obese, healthy subjects without dyspnea.


METHODS
Prospective, open.


METHODS
Pulmonary function test laboratory, Veterans Administration Medical Center.


METHODS
Twenty-three obese male subjects (each with a body mass index [BMI] of > 28 kg/m2) with an FEV1 level and an FEV1/FVC ratio > or = 80% of predicted and no coexisting conditions. Fifteen complained of dyspnea, where eight denied having it, at rest.


RESULTS
Standard PFT parameters and maximum static inspiratory (P(Imax)) and expiratory (P(Emax)) mouth pressures were determined. Subjects with dyspnea had similar age and height but larger body weight (113.9+/-5.0 vs 97.4+/-2.6 kg, p = 0.03) and BMI (37.4+/-1.6 vs 31.8+/-0.7 kg/m2, p = 0.02) than subjects without dyspnea, and a greater number of them were current or previous smokers. Forced expiratory flow at 75% vital capacity (54.9+/-6 vs 75.5+/-7% predicted, p = 0.05), maximum voluntary ventilation (MVV; 90.2+/-3.8 vs 107.8+/-9.3% predicted, p = 0.05), and P(Emax) (77+/-2 vs 97.8% predicted, p = 0.007) were significantly reduced in the group of subjects with dyspnea. Large airway function (FVC, FEV1, and FEV1/FVC ratio), lung volumes, and gas exchange parameters were similar between the two groups.


CONCLUSIONS
Some obese, but otherwise healthy, individuals experience dyspnea at rest. Reduced P(Emax) and MVV combined with greater body mass and peripheral airway disease are most likely responsible for the sensation of dyspnea in these individuals.
Sahebjami
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Department of Veterans Affairs Medical Center, Department of Medicine, University of Cincinnati College of Medicine, OH, USA.
D004417:Dyspnea / Q000209:etiology* / Q000503:physiopathology; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008451:Maximal Voluntary Ventilation; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D011446:Prospective Studies; D015656:Respiratory Mechanics; D012132:Respiratory Muscles / Q000503:physiopathology; D012146:Rest; D014797:Vital Capacity