Knee extensor muscle strength predicts ability to exercise in elderly HF patients

In elderly heart failure (HF) patients, knee extensor muscle strength appears to be an important determinant of exercise capacity, particularly in those with sarcopoenia, reports a recent study.

Researchers measured the 6-minute walking distance (6MWD) in 186 consecutive elderly patients with HF (mean age, 79.8±9.64 years; 105 females). None of the participants had documented physical disability. Knee extensor muscle strength was measured using a hand-held dynamometer, placed on the participant’s ankle and fastened to a table leg. Extensions were performed twice for each leg.

Seventy-seven participants were found to have sarcopoenia, yielding a prevalence rate of 41.3 percent. Ninety-two percent had New York Heart Association functional class III at baseline.

Multiple regression analysis found that walking speed was significantly predictive of 6MWD (B, 243.943±19.595; p<0.001), as were age (B, –1.542±0.614; p=0.013) and calf circumference (B, 2.914±1.411; p=0.041).

Knee extensor muscle strength likewise emerged as a factor significantly and positively correlated with 6MWD (B, 15.225±3.874; p<0.001). This effect was only evident and significant in those with sarcopoenia (B, 14.139±6.08; p=0.023). Walking speed also emerged as an independent determinant of 6MWD in both patient subgroups.

“To our knowledge, this study is the first report to demonstrate the relationship between the 6MWD and muscle strength in elderly patients with HF with and without sarcopoenia,” said researchers.

“[O]ur findings add new and meaningful information regarding the exercise prescription for improving the 6MWD. Resistance training appears to be the primary exercise intervention for patients with HF with sarcopoenia,” they added.