Heart failure: Impact of exercise intolerance on functional capacity and quality of life

Abstract

Introduction: Heart failure is associated with significant limitations in physical performance, notably exercise intolerance and its repercussions on functional capacity and quality of life. These limitations involve various cardiovascular, respiratory, and muscular components and may manifest as reduced cardiorespiratory fitness, dyspnea, fatigue, and impaired performance in functional activities. Objective: To synthesize the available evidence on exercise intolerance in individuals with heart failure, considering its impact on functional capacity and quality of life, the key cardiovascular, respiratory, and muscular factors associated with exercise limitation, and the effects of the therapeutic strategies investigated on these outcomes. Methods: This is an integrative literature review of a qualitative and descriptive nature, conducted using the PubMed/MEDLINE, SciELO, and Virtual Health Library (VHL) databases. Data were analyzed descriptively and qualitatively, considering study design, objectives, interventions or factors investigated, and main functional outcomes. Results: Initially, 65 records were identified, of which 15 duplicates were removed. Fifty studies underwent screening by title and abstract, with 20 being excluded. Of the 30 articles evaluated in full, 18 were excluded for failing to meet eligibility criteria, resulting in a final sample of 12 studies. The 12 included studies employed various designs and investigated parameters such as peak oxygen consumption, six-minute walk test distance, cardiorespiratory fitness, peripheral and respiratory muscle strength, dyspnea, fatigue, physical performance, functional capacity, and quality of life. The findings highlighted the multifactorial nature of exercise intolerance in heart failure and its relationship with impaired functional capacity and quality of life. Various strategies were investigated, including aerobic training, muscle strengthening, home-based and supervised training, inspiratory muscle training, and specific cardiovascular interventions. Overall, the studies indicated favorable effects of these approaches on components of exercise capacity and functionality, although methodological heterogeneity limits direct comparisons and the determination of superiority among the interventions. Conclusion: Exercise intolerance is a significant component of functional impairment in heart failure and is associated with reduced quality of life. These findings underscore the importance of assessing exercise intolerance when monitoring individuals with heart failure, taking into account its various determinants and functional consequences. However, the heterogeneity of the studies and the lack of a standardized assessment of risk of bias in this review indicate a need for caution when interpreting the results and for more methodologically robust investigations.