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Maximum oxygen uptake corrected for skeletal muscle mass accurately predicts functional improvements following exercise training in chronic heart failure
Author(s) -
LeMaitre John P.,
Harris Stuart,
Hannan Jim,
Fox Keith A.A.,
Denvir Martin A.
Publication year - 2006
Publication title -
european journal of heart failure
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.149
H-Index - 133
eISSN - 1879-0844
pISSN - 1388-9842
DOI - 10.1016/j.ejheart.2005.07.011
Subject(s) - skeletal muscle , medicine , heart failure , vo2 max , cardiology , treadmill , gastrocnemius muscle , physical therapy , physical medicine and rehabilitation , heart rate , blood pressure
Background: Skeletal muscle mass and peak oxygen uptake are important predictors of functional status and outcome in patients with stable chronic heart failure. Aims: To assess changes in skeletal muscle mass and peak oxygen uptake following an exercise training program. Methods: Thirty‐six patients with moderate stable chronic heart failure were randomly allocated to either a bicycle ergometer (bike) or functional electrical muscle stimulators (FES) applied to quadriceps and gastrocnemius muscles to be used daily for six weeks. Dual‐energy X‐ray absorptionometry (DEXA) scanning was performed before and after training along with symptom limited cardiopulmonary exercise test, quadriceps strength and fatigue resistance, and 6‐min walk test. Results: Both exercise modalities resulted in improvements in treadmill exercise time, leg strength, 6‐min walk test and peak oxygen uptake per kilogram of skeletal muscle. Despite significant improvements in functional capacity, there were no significant changes in body composition for total skeletal muscle mass, leg muscle mass or total body fat content. Skeletal muscle mass was strongly predictive of maximum oxygen uptake at baseline ( r =0.61, p <0.001) and after exercise training ( r =0.68, p <0.001). Conclusions: In moderate stable chronic heart failure, exercise training using bicycle ergometer or FES results in favourable qualitative rather than quantitative changes in skeletal muscle. Correction of maximum oxygen uptake for skeletal muscle mass rather than total body mass is a more sensitive measure of changes associated with exercise training.