Effect of weight loss via bariatric surgery for class III obesity on exertional breathlessness

We examined the impact of bariatric surgery on cardiometabolic, ventilatory and breathlessness responses to incremental cycle exercise testing in adults with class III obesity (n = 6). O-2 consumption, CO2 production, minute ventilation ((V)over dot) and breathing frequency were reduced during submaximal exercise after surgery. Inspiratory capacity (IC) and inspiratory reserve volume were lower at rest and any given (V)over dot(E) during exercise after surgery. In the transition from rest to peak exercise, dynamic IC decreased by 0.13 L before surgery and increased by 0.21 L after surgery. Breathlessness intensity ratings were lower during exercise at power outputs >= 75-watts after surgery (e.g., by 1.0 and 1.4 Borg 0-10 scale units at 75-watts and the highest equivalent power output of 117-watts, respectively). In contrast, bariatric surgery had no effect on breathlessness-(V)over dot(E) relationships during exercise. In conclusion, relief of exertional breathlessness following bariatric surgery could not be explained by improved dynamic breathing mechanics, but reflected the awareness of reduced metabolic and ventilatory requirements of exercise.