Upper and Lower Extremity Muscle Strength Levels Associated With an Exercise Capacity of 5 Metabolic Equivalents in Male Patients With Heart Failure

PURPOSE: Exercise capacity of fewer than 5 metabolic equivalents (METs) has been associated with high risk of death and poor physical functioning in male patients with heart failure (HF). Therefore, we aimed to determine upper and lower extremity muscle strength levels required to attain an exercise capacity of 5 or more METs in male outpatients with HF. METHODS: We enrolled 148 male HF patients (age 60.1 +/- 1.0 years). Peak oxygen uptake (peak o2) was assessed by cardiopulmonary exercise testing (CPX). After CPX, we further divided the patients into groups according to exercise capacity: 5 or more METs (group A, n = 85) and fewer than 5 METs (group B, n = 63). Handgrip strength and knee extensor and flexor muscle strengths were assessed as indices of upper and lower extremity muscle strength, respectively. Receiver operating characteristic curves were used to select cutoff values for upper and lower extremity muscle strength resulting in an exercise capacity of 5 or more METs in these patients. RESULTS: Exercise capacity of 5 or more METs in male HF patients was equivalent to approximately 35.2 kgf of handgrip strength and 1.70 Nm/kg of knee extensor and 0.90 Nm/kg of knee flexor muscle strengths. CONCLUSIONS: These upper and lower extremity muscle strength values may be useful target goals for improvement of exercise capacity, risk management, and activities of daily living in male HF patients.