Exercise physiology in obese subjects: Respiratory function

Obesity can have significant adverse effects on the respiratory system, which stems from the fact that the increased adipose tissue mass in obese individuals (adipose tissue predominantly in the chest wall and abdomen) reduces certain lung volume sub-divisions. Low lung volume breathing at rest and during exercise alters basic respiratory mechanics, which predispose healthy obese adults to abnormalities like increased ventilatory demand, increased oxygen cost of breathing, gas exchange impairments, and increased risk for developing expiratory flow limitation. In addition, a large proportion of healthy obese individuals have exertional dyspnea, which may result in exercise intolerance, and could diminish participation in regular physical activity and thus, is an immensely important national health concern. This chapter will focus on how the changes in lung volume sub-divisions observed with obesity affect resting lung function as well as respiratory and ventilatory dynamics during exercise.