Relation between physical activity and exercise capacity of ≥5 metabolic equivalents in middle- and older-aged patients with chronic heart failure

Purpose: Patients with exercise capacity of <5 metabolic equivalents (METs) are considered to have a high risk of death. The aim of this study was to determine age-related differences in physical activity associated with an exercise capacity of ≥5 METs in chronic heart failure (CHF) outpatients. Methods: We enrolled 157 stable CHF patients (79.6% men, age 60.3 ± 11.5 years). Patients were divided into two age-based groups (middle-aged, <65 years, n 97) and (older-aged, ≥65 years, n 60). Peak oxygen uptake (peak V̇ O2) was assessed by cardiopulmonary exercise testing. We further divided patients into groups according to exercise capacity: ≥5 METs and <5 METs. Physical activity was assessed by measuring the average number of steps/day for 1 week with an electronic pedometer. Results: Receiver-operating characteristic curves were used to select cutoff values for steps associated with an exercise capacity of ≥5 METs in the middle- and older-aged patients. Cutoff values of 6045 steps in the middle-aged and 6070 steps in the older-aged patients were determined. Conclusions: Both middle- and older-aged CHF patients with exercise capacity of ≥5 METs completed approximately 6000 steps/day. This could become a target amount for minimal physical activity that could contribute to increased exercise capacity in CHF patients.