Activity-related dyspnea and exercise intolerance in chronic obstructive pulmonary disease: recent insights.

PURPOSE OF REVIEW: Exertional dyspnea and exercise intolerance remain key patient-related outcomes in chronic obstructive pulmonary disease (COPD). Improvement in treatment strategies is pendant further understand of their underpinnings across the spectrum of disease severity.

RECENT FINDINGS: Emerging literature has been reviewed based on a conceptual framework that relates ventilatory demand to capacity under the modulating influence of sub-cortical and cortical centers (symptom perception and affective interpretation). Evidence supporting these fundamental tenets is critically appraised, focusing on mechanistic and interventional studies that shed novel light on the sources of heightened and/or mechanically constrained ventilation. Mechanistic studies using proxies of the inspiratory neural drive (e.g., diaphragm electromyography) were particularly informative, as well as interventional trials aimed at decreasing afferent stimulation and/or symptom perception via pharmacological (e.g., low-dose opiates in selected patients, high flow oxygen, oral nitrate) and nonpharmacological (e.g., novel exercise training paradigms, inspiratory muscle training, breathing techniques) interventions.

SUMMARY: Therapeutic and rehabilitative strategies to lessen dyspnea's devastating impact on quality of life should minimize demand in the setting of reduced capacity and increased sensation awareness in COPD. The most successful attempts so far have amalgamated pharmacological and nonpharmacological approaches tailored to the main underlying mechanisms on an individual basis.