Age no barrier to exercise benefits in heart failure
MedWire News: Exercise training reduces markers of muscle breakdown in patients with chronic heart failure (CHF), and does so regardless of a patient's age, show findings from a randomized trial.
"Many physicians - and insurance companies - still believe that cardiac rehabilitation does not really help in old age. This study clearly falsifies this belief," said lead researcher Stephan Gielen (Martin-Luther-University of Halle, Germany) in a press statement.
Gielen et al specifically addressed the effect of age in their study. They recruited 60 CHF patients and 60 healthy controls, with half of each group being aged 55 years or younger and half aged at least 65 years. "In previous training studies in heart failure patients, elderly individuals were mostly underrepresented, making it difficult to extrapolate the beneficial effects of training interventions to the age stratum in which heart failure is most prevalent," they say.
The researchers found that, overall, 4 weeks of supervised endurance training significantly reduced levels of the muscle-specific ubiquitin ligase MuRF-1 messenger RNA in vastus lateralis muscle biopsies taken from CHF patients relative to those from patients assigned to a nonexercising control group.
MuRF-1 is involved in tagging proteins to be targeted for degradation in proteasomes. At the start of the study, levels of MuRF-1 were significantly higher in the CHF patients than in control participants.
But during training, MuRF-1 levels fell by about a third in the CHF patients who were assigned to undertake exercise, whereas exercise had no significant effect on levels in controls.
The effect of exercise was equally strong in CHF patients in the younger and older age strata, causing MuRF-1 reductions of 32.8% and 37.0%, respectively.
At baseline, CHF patients also had significantly reduced levels of the anabolic factor insulin-like growth factor-I in quadriceps biopsies, relative to controls. During exercise training, levels increased about twofold. This, together with the reduction in MuRF-1 levels, suggests that exercise reduces the anabolic-catabolic imbalance in the muscles of patients with CHF, say Gielen et al.
"Understanding the specific changes causing the catabolic-anabolic imbalance in CHF is an essential first step in the development of pharmaceutical intervention strategies aimed at blocking muscle catabolism in CHF," they conclude in Circulation.
"For the present, endurance training provides an excellent anabolic stimulus in both younger and elderly patients with heart failure and should be regarded as a key component of an anticatabolic treatment approach in heart failure patients of all age groups."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012
By Eleanor McDermid