Acute cardiovascular responses to leg-press resistance exercise in heart transplant recipients

Background: Reduced skeletal muscle strength is characteristic of individua ls following heart transplantation. Weight lifting exercise has been demons trated as an effective means by which to increase muscular strength in othe r cardiac patients but the appropriateness of this form of exercise in hear t transplant patients has not been investigated. The purpose of this study was to describe the cardiovascular responses of heart transplant patients t o a single, prolonged bout of weight lifting training. Methods: Twenty-thre e heart transplant recipients were stratified into early (Early; 3 months; n=6), intermediate (Intermediate; 1-3 years, n=7) and late (Late; 5-14 year s; n=10) post transplant groups and studied in four experimental conditions : supine rest, upright rest, single leg-press exercise (28 repetitions over 2 min 20 s at 50% 1 repetition maximum) and recovery. Swan-Ganz catheteriz ation allowed measurement of right heart pressures and cardiac output by th ermodilution. Systemic arterial pressures and heart rate were measured cont inuously using a non-invasive finger cuff. Results: Cardiac output increase d by 30, 40 and 54% during exercise in Early, Intermediate and Late, respec tively. Heart rate increased by 4.5% in Early compared to 11 and 16% increa ses in Intermediate and Late. At peak exercise, systolic blood pressures re ached average values of 179 +/- 9, 180 +/- 14 and 176 +/- 8 mmHg in Early, Intermediate and Late, respectively. Average mean pulmonary artery pressure did not exceed 30 mmHg and average pulmonary wedge pressure did not exceed 15 mmHg in any group during the exercise. Conclusions: These observations indicate that a lengthened set of single leg-press exercise at a moderate l ifting intensity can be performed within safe and acceptable physiological limits in patients following heart transplantation. To better address the s pecific rehabilitation needs of heart transplant recipients, future researc h should focus on developing training programs which include weight lifting exercise. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.