Adiposity facilitates increased strength capacity in heart failure patients with reduced ejection fraction

Background: Obesity is associated with relatively improved prognosis among heart failure (HF) patients. Mechanisms explaining this so-called "obesity paradox" have been unclear. We hypothesized that increased adiposity may contribute to increased strength capacity, and may thereby facilitate clinical benefits.

Methods and results: In a controlled, cross-sectional study, adults aged ≥ 50 years with HF with reduced ejection fraction (HFREF) (LVEF ≤ 40%) were compared to age matched controls. Body composition was determined by dual-energy X-ray absorptiometry (DXA). Aerobic (cardiopulmonary exercise testing), maximum strength (one repetition maximum [1RM]), and power (submaximal resistance/time) were assessed. 70 adults (31 HFREF, 39 controls; mean age 66.2 ± 9.6 years) were studied. Peak oxygen consumption (VO2) (15.4 ± 4.2 vs. 23.4 ± 6.6 ml O2 · kg(-1) · min(-1), p<0.0001), 1RM (154.8 ± 52.0 vs. 195.3 ± 56.8 kg, p<0.01) and power (226.4 ± 99.2 vs. 313.3 ± 130.6, p<0.01) were lower in HFREF vs. controls. 1 RM correlated with total fat (r=0.56, p<0.01), leg fat (r=0.45, p<0.05) and arm fat (r=0.39, p<0.05) in HFREF. Moreover, among HFREF patients with a high (≥ 30 kg/m(2)) body mass index (BMI), 1RM and fat mass were significantly greater than those with lower (<30 kg/m(2)) BMIs. Correlations between 1 RM and total fat (r=0.65, p<0.05) and leg fat (r=0.64, p<0.05) were particularly notable in the high BMI subgroup.

Conclusion: Increased adiposity correlates with relatively greater strength in HFREF patients which may explain some of the clinical benefits that result from obesity.