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Collins EG, Langbein E, Orebaugh C. Can exercise training improve QOL in heart failure patients? A pilot study. Paper presented at: International Society for Heart & Lung Transplantation Annual Meeting; 1998 Jun 1; Chicago, IL.
In this pilot study, subjects with left ventricular dysfunction (LVEF 40%) completed six-weeks of moderate intensity exercise training to determine if improvements in QOL are associated with increased aerobic capacity. Subjects were 10 males (53-84 yr of age); eight completed exercise training and two served as controls. Baseline EF were 28 13% and 26% for the training (Tgrp) and control (Cgrp) groups respectively. At baseline, no significant differences were found between the two groups. Each subject repeated a symptom limited modified Naughton treadmill test with metabolic and hemodynamic measures, Rand Short Form 36, Minnesota Living with Heart Failure questionnaire, Cardiac Exercise Self-Efficacy Instrument, and a three-day activity log. Baseline maximal oxygen uptake (VO2max) were 18.1 2.8 for the Tgrp and 17.5 ml kg-1min-1 for the Cgrp (range = 16.2 - 18.8). Due to the small sample size and lack of a normal distribution, the Wilcoxon Matched-Pairs Signed-Rank Test was used to analyze the data. An = 0.025 was required for statistical significance. The 8% improvement in VO2max of the Tgrp was not statistically significant (p > 0.025). However, the 19% increase in total treadmill exercise time was significant (p < 0.02). An 8% decline in time and a 7% decline in VO2max were found in the two control subjects. QOL scores are expressed in terms of effect size relative to change (0.20 = small change, 0.50 = moderate change, and > 0.80 = large change). For the Tgrp, a large change was found in the subjects' vitality (energy or pep) from baseline to six-weeks (ES = 0.90). Moderate to small improvements were seen in the subjects' confidence in their ability to exercise (ES = 0.42), their mental health (ES = 0.44), and their overall sense of well-being (ES = 0.33). Due to the small group size, no meaningful interpretation of the Cgrp QOL data could be made. Analysis of the subjects' self-report, three-day activity log revealed an increase in estimated daily energy expenditure. At baseline, subjects utilized 1668 700 kcalsday. After six-weeks of training, subjects were more active, utilizing 2179 997 kcalsday . This difference of 511 kcals more per day translates into a 31% increase in caloric expenditure. Whereas the ability to generalize from the findings of this study is limited by the sample size, it is noteworthy that there was a positive association between the HF patients' perceived QOL and their improvements in exercise tolerance and increased activities of daily living. A randomized clinical trial is underway to further evaluate the strength of this important relationship.