A Home-Based Walking Program Improves Respiratory Endurance in Patients With Acute Myocardial Infarction: A Randomized Controlled Trial.
BACKGROUND
The purpose of this study was to evaluate respiratory muscle strength and endurance in the inpatient period in patients who recently experienced myocardial infarction (MI) and investigate the effects of a home-based walking program on respiratory strength and endurance in low-risk patients after MI.


METHODS
Patients were randomized into a usual-care group (UCG) entailing regular care (n = 23) and an intervention group (IG) entailing an outpatient home-based walking program (n = 31). Healthy sex- and age-matched participants served as a control group for respiratory endurance variables. Respiratory muscle strength was evaluated through maximal inspiratory pressure (MIP) and endurance during the inpatient period, at 15 days, and at 60 days after MI. Submaximal functional capacity was determined by a 6-minute walk test (6MWT) at hospital discharge and 60 days after MI.


RESULTS
Both groups showed impaired inspiratory muscle strength at hospital discharge. When compared with healthy individuals, after MI, patients had worse respiratory muscle endurance pressure (PTHmax = 73.02 ± 8.40 vs 44.47 ± 16.32; P < 0.05) and time (Tlim = 324.1 ± 12.2 vs 58.7 ± 93.3; P < 0.05). Only the IG showed a significant improvement in MIP and PTHmax at 15 days and 60 days after MI (P < 0.05). When comparing groups, the IG achieved higher values for MIP, PTHmax, and Tlim 15 and 60 days after MI (P < 0.01). The 60-day assessment revealed that the 6MWT distance and level of physical activity was significantly higher in the IG compared with the UCG.


CONCLUSIONS
Low-risk patients recently experiencing MI demonstrate impaired MIP and respiratory endurance compared with healthy participants. A home-based walking program improved respiratory endurance and functional capacity.