To determine the effect of resistance exercise training (ET) on glucocorticoid-induced myopathy in heart transplant recipients (HTR), 14 male HTR were randomly assigned to a ET group that trained for 6 months (54± 3 yr old; mean ± SD) or a control group (51 ± 8 yr old; mean ± SD).Methods:
Fat mass, fat-free mass, and total body mass were measured by dual-energy x-ray absorptiometry before and 2 months after transplantation (Tx), and after 3 and 6 months of ET or control period. The exercise regimen consisted of lumbar extension (MedX) performed 1 d·wk-1 and variable resistance exercises (Nautilus) performed 2 d·wk-1. PreTx body composition did not differ between groups.Results:
At 2 months after Tx, fat-free mass was significantly decreased below baseline in both control (-3.4 ± 2.1%) and ET groups (-4.3 ± 2.4%). Fat mass was significantly increased at 2 months after Tx in both the control (+8.3 ± 2.8%) and ET groups (+7.3 ± 4.0%). Six months of ET restored fat-free mass to levels 3.9 ± 2.1% greater (P≤ 0.05) than before Tx. Fat-free mass of the control group decreased progressively to levels that were 7 ± 4.4% lower than preTx values(P ≤ 0.05). Both groups increased knee extension, chest press, and lumbar extensor strength, but improvements in the ET group were four- to six-fold greater (P ≤ 0.05).Conclusion:
Our results demonstrate that glucocorticoid-induced changes in body composition in HTR occur early after Tx. However, 6 months of specific ET restores fat-free mass to levels greater than before Tx and dramatically increases skeletal muscle strength. Resistance exercise, as part of a strategy to prevent steroid-induced myopathy, appears to be safe and should be initiated early after heart Tx.