SESSION TITLE: Pulmonary Physiology Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM
PURPOSE: Dyspnea on exertion is prevalent in obesity and contributes to physical activity limitation and avoidance. Surgically induced weight loss in obese individuals has been shown to relieve exertional dyspnea and improve functional capacity. The mechanisms responsible for these improvements, however, remain poorly understood and represent the primary aim of this preliminary study.
METHODS: Oxygen uptake (V̇O2), heart rate (HR), ventilation (V̇E), tidal volume (VT), breathing frequency (fR), dynamic operating lung volume, exercise endurance time (EET) and dyspnea responses to symptom-limited incremental cycle exercise testing (25 watts/2-min) were compared in 6 morbidly obese (BMI ³35 kg/m2; 2M: 4F) adults aged 43.7 ± 2.8 yrs before (PRE) and 3-mo after bariatric surgery (POST), which decreased body mass by ~25 kg (129.4 ± 6.2 vs. 105.6 ± 5.8 kg) and BMI by ~10 kg/m2 (46.3 ± 2.3 vs. 37.8 ± 2.1 kg/m2).
RESULTS: Compared to PRE, bariatric surgery was associated with an increase in EET (10.1 ± 1.0 vs. 11.6 ± 1.6 min) and peak work rate (133.3 ± 10.5 vs. 154.2 ± 20.8 watts). Mean values of V̇O2, HR, V̇E, fR and dyspnea were reduced, while VT remained unchanged at any standardized absolute submaximal work rate during exercise in POST vs. PRE. The ratios of inspiratory reserve volume and inspiratory capacity to vital capacity were reduced at rest and at any standardized absolute V̇E during exercise in POST vs. PRE. Nevertheless, dyspnea intensity-V̇E relationships were superimposed throughout exercise in POST vs. PRE.
CONCLUSIONS: Extreme weight loss 3-mo after bariatric surgery was associated with improved functional capacity and exertional dyspnea. Relief of activity-related dyspnea following bariatric surgery could not be easily explained by increased VT expansion and/or improved behavior of dynamic operating lung volumes, but likely reflected the awareness of reduced V̇E during exercise.
CLINICAL IMPLICATIONS: The preliminary results of this study suggest that, in addition to weight reduction, any intervention capable of reducing metabolic and ventilatory demands during physical activity in morbidly obese adults should effectively relieve exertional dyspnea, with attendant improvements in functional capacity.
DISCLOSURE: The following authors have nothing to disclose: Sara Abdallah, Ryan Reid, Ross Andersen, Dennis Jensen
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