Cardiopulmonary rehabilitation for obese sleep-disordered breathing: a new treatment frontier?

The health benefits of routine exercise in otherwise healthy people, including in those who are obese, are well proven.1 Exercise improves cardiorespiratory fitness and improves blood supply to the musculature to enhance oxidative metabolism and overall efficiency of energy expenditure. There is also evidence showing the benefits of exercise might extend to people with debilitating conditions including congestive heart failure (CHF),2 COPD3 and more recently, obesity hypoventilation syndrome (OHS).4 In these populations, exercise training as part of a rehabilitation programme has been shown to improve exercise and functional capacity as well as overall quality of life. However, there are inherent (disease-specific) physiological limitations that pose significant barriers to full engagement in exercise training in people with chronic illness. For example, in the setting of pulmonary rehabilitation in COPD, exercise-induced dynamic hyperinflation increases the work of breathing, resulting in severe dyspnoea and a reduction in exercise tolerance, making it difficult for patients to adhere to exercise programmes.5 As a solution to this, rehabilitation programmes, particularly in COPD, are increasingly using supportive methods in an attempt to reduce the physiological burden of exercise and improve exercise tolerance and capacity with anticipated positive effects on health outcomes. For example, non-invasive ventilation (NIV) that is deployed during exercise in patients with COPD undergoing pulmonary rehabilitation is thought to unload respiratory muscles and reduce the work of breathing, reducing diaphragm fatigue and dyspnoea. While this is supported by a number of studies showing an increase in training intensity, the effect on subsequent exercise capacity seems variable and currently the benefits remain unclear.6 Another technique used to improve exercise tolerance involves respiratory muscle training (RMT), incorporating both respiratory muscle strength (resistive/threshold) and respiratory endurance (isocapnic hyperpnoea) training. In healthy individuals, …