RATIONALE: Although exertional dyspnea in obesity is an important and prolific clinical concern, the underlying mechanism remains unclear. OBJECTIVES: To investigate whether dyspnea on exertion in otherwise healthy obese women was associated with an increase in the oxygen cost of breathing or cardiovascular deconditioning. METHODS: Obese women with and without dyspnea on exertion participated in two independent experiments (n = 16 and n = 14). All participants underwent pulmonary function testing, hydrostatic weighing, ratings of perceived breathlessness during cycling at 60 W, and determination of the oxygen cost of breathing during eucapnic voluntary hyperpnea at 40 and 60 L/min. Cardiovascular exercise capacity, fat distribution, and respiratory mechanics were determined in 14 women in experiment 2. Data were analyzed between groups by independent t test, and the relationship between the variables was determined by regression analysis. MEASUREMENTS AND MAIN RESULTS: In both experiments, breathlessness during 60 W cycling was markedly increased in over 37% of the obese women (P < 0.01). Age, height, weight, lung function, and %body fat were not different between the groups in either experiment. In contrast, the oxygen cost of breathing was significantly (P < 0.01) and markedly (38-70%) greater in the obese women with dyspnea on exertion. The oxygen cost of breathing was significantly (P < 0.001) correlated with the rating of perceived breathlessness obtained during the 60 W exercise in experiment 1 (r(2) = 0.57) and experiment 2 (r(2) = 0.72). Peak cardiovascular exercise capacity, fat distribution, and respiratory mechanics were not different between groups in experiment 2. CONCLUSIONS: Dyspnea on exertion is prevalent in otherwise healthy obese women, which seems to be strongly associated with an increased oxygen cost of breathing. Exercise capacity is not reduced in obese women with dyspnea on exertion.
RATIONALE: Although exertional dyspnea in obesity is an important and prolific clinical concern, the underlying mechanism remains unclear. OBJECTIVES: To investigate whether dyspnea on exertion in otherwise healthy obesewomen was associated with an increase in the oxygen cost of breathing or cardiovascular deconditioning. METHODS:Obesewomen with and without dyspnea on exertion participated in two independent experiments (n = 16 and n = 14). All participants underwent pulmonary function testing, hydrostatic weighing, ratings of perceived breathlessness during cycling at 60 W, and determination of the oxygen cost of breathing during eucapnic voluntary hyperpnea at 40 and 60 L/min. Cardiovascular exercise capacity, fat distribution, and respiratory mechanics were determined in 14 women in experiment 2. Data were analyzed between groups by independent t test, and the relationship between the variables was determined by regression analysis. MEASUREMENTS AND MAIN RESULTS: In both experiments, breathlessness during 60 W cycling was markedly increased in over 37% of the obesewomen (P < 0.01). Age, height, weight, lung function, and %body fat were not different between the groups in either experiment. In contrast, the oxygen cost of breathing was significantly (P < 0.01) and markedly (38-70%) greater in the obesewomen with dyspnea on exertion. The oxygen cost of breathing was significantly (P < 0.001) correlated with the rating of perceived breathlessness obtained during the 60 W exercise in experiment 1 (r(2) = 0.57) and experiment 2 (r(2) = 0.72). Peak cardiovascular exercise capacity, fat distribution, and respiratory mechanics were not different between groups in experiment 2. CONCLUSIONS:Dyspnea on exertion is prevalent in otherwise healthy obesewomen, which seems to be strongly associated with an increased oxygen cost of breathing. Exercise capacity is not reduced in obesewomen with dyspnea on exertion.
Authors: Maria Theresa D Opina; Tina E Brinkley; Michelle Gordon; Mary F Lyles; Barbara J Nicklas Journal: J Gerontol A Biol Sci Med Sci Date: 2019-11-13 Impact factor: 6.053
Authors: Yong Liu; Roy A Pleasants; Janet B Croft; Njira Lugogo; Jill Ohar; Khosrow Heidari; Charlie Strange; Anne G Wheaton; David M Mannino; Monica Kraft Journal: Respir Med Date: 2015-05-16 Impact factor: 3.415