Respiratory muscle strength in patients with pulmonary hypertension: The relationship with exercise capacity, physical activity level, and quality of life.

INTRODUCTION: Pulmonary hypertension (PH) is characterized by exertional dyspnea, fatigue, chest pain, dizziness, and syncope. Physical activity, peripheral, and respiratory muscle strength reduces in pateints with PH. Little is known about respiratory muscle weakness and related outcomes.

OBJECTIVES: The aims of the study were to determine respiratory muscle strength and to investigate the relationship between respiratory muscle strength and spirometric measurements, exercise capacity, physical activity level, quality of life, and pulmonary hemodynamics in patients with PH.

METHODS: In total, 33 patients aged 25-80 years who were diagnosed as having PH and 24 healthy volunteers were included in the study. To measure respiratory function, spirometry, maximal inspiratory (MIP), and expiratory pressures (MEP) were used. Physical activity level was determined with activity monitoring (SenseWear Armband) and the International Physical Activity Questionnaire-Short Form. Exercise capacity was determined using the 6-minute walk test. Quality of life was evaluated with the Minnesota Living with Heart Failure Questionnaire (MLHFQ).

RESULTS: Maximal inspiratory pressure and MEP values of the patients with PH were significantly lower than the age- and sex-matched healthy controls (P < .0001). Significant relationships were found between the MIP and six MWD (r = .40, P = .02), vigorous physical activity (r = .38, P = .03), moderate physical activity (r = 61, P < .001), and arm band-average metabolic equivalent (r = .39, P = .02).

CONCLUSION: The relationship between maximum inspiratory pressure, exercise capacity, and physical activity level showed that a decrease in exercise capacity or physical activity level may be a predictor for decreased MIP.