Dyspnea and exercise intolerance in breast cancer survivors: The role of inspiratory muscle weakness

Background: Women who have been successfully treated for breast cancer have been shown to have significantly greater dyspnea and activity restriction than healthy individuals but contributory mechanisms are unknown. Methods: We therefore compared dyspnea assessments, respiratory and peripheral muscle strength, pulmonary function tests and cardiopulmonary responses to incremental treadmill exercise in 29 women treated for breast cancer and 29 age-matched healthy controls. Results: On average, the cancer group had a >20% (p 10% lower at rest and throughout exercise in the cancer group, resulting in an earlier tidal volume inflection/plateau and a shallower breathing pattern at high exercise intensities (all p Conclusions: Activity-related dyspnea, global skeletal muscle weakness and deconditioning were more pronounced in the cancer group than in healthy controls. Greater exertional dyspnea in the cancer group was associated with greater inspiratory muscle weakness, reduced IC and tidal volume expansion during exercise. The corollary is that specific inspiratory muscle training in conjunction with general reconditioning may relieve dyspnea and improve exercise tolerance in breast cancer survivors.