Exercise capacity and obstructive sleep apnea in lean subjects.
BACKGROUND
Conflicting data regarding exercise capacity and obstructive sleep apnea (OSA) have been published, which may be partially explained by the difficulty of controlling all of the confounding factors. The aim of this study is to evaluate the exercise, anthropometric, and blood parameters in lean, sedentary patients with OSA compared with controls.


METHODS
Fifty-four lean subjects (including 27 patients with OSA and 27 controls) were selected. The control group was matched for age and gender. All subjects underwent polysomnography, anthropometric measures, a cardiorespiratory exercise test, two-dimensional transthoracic echocardiography, and spirometry.


RESULTS
The mean age was 52.9 +/- 7.9 years in subjects with OSA and 52.8 +/- 8.1 years in controls (P = .95). The cervical circumference was greater in the lean OSA group when compared with the controls (33.7 +/- 3.5 cm vs 31.4 +/- 2.8 cm; P = .01). There were statistical differences in the apnea-hypopnea index, minimal oxygen saturation, and mean oxygen saturation in the lean patients with OSA. Glycemia was higher in the lean OSA group (115.1 +/- 50.1 mg/dL vs 94.2 +/- 9.8 mg/dL; P = .04). There were no differences between groups in the peak oxygen consumption (Vo(2)), anaerobic threshold (AT), respiratory exchange ratio (RER), BP, and heart rate.


CONCLUSIONS
High glycemia and cervical circumference enlargement are the main characteristics of lean patients with OSA. Exercise performance is similar between groups, considering the peak Vo(2), AT, and RER. These results suggest that OSA does not impair functional capacity in lean subjects and that obesity probably participates in the diminished cardiopulmonary capacity observed in patients with OSA.
Cardiology Discipline, Medicine Department, Universidade Federal de São Paulo, São Paulo, Brazil.
Camila F
CF
Rizzi
Fátima
F
Cintra
Thais
T
Risso
Cristiane
C
Pulz
Sergio
S
Tufik
Angelo
A
de Paola
Dalva
D
Poyares
D001794:Blood Pressure / Q000502:physiology; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011379:Prognosis; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology*; D013851:Thinness / Q000150:complications / Q000503:physiopathology*