Effects of adding high- vs low-intensity resistance training to endurance training in patients with heart failure: preliminary results of a randomized controlled trial

Abstract

Background: In current ESC/EAPC guidelines, adding resistance training to endurance training is advised for patients with heart failure (HF), but the optimal intensity of the resistance training is unknown (40‐80% of 1RM is advised). Purpose: To investigate the effects of high‐ vs low‐intensity resistance training as an adjunct to endurance training on: Aerobic capacity (primary outcome), walking capacity, muscle strength and quality of life in patients with HF. Methods: Forty patients with HF were consecutively recruited in the cardiac rehabilitation center of the Hospital East‐Limburg in Belgium. Patients were block‐randomized (by age and sex) by an independent researcher to receive maximally 45 supervised sessions (3x/week) of high‐intense (HI: 3 exercises, 3x12 repetitions, 55‐70%1RM) or low‐intense resistance training (LI: 3 exercises, 3x22 repetitions, 35‐40%1RM) as an adjunct to endurance training (30 min/session; 50‐75% VO2max). The aerobic capacity (VO2max) was measured by a blinded assessor with a ramp cardiopulmonary cycling test (+5‐30W/min). Walking distance was assessed with a 6‐minute walk test (6MWT), maximal strength with 1RM (leg‐press, pulldown and dip), and quality of life with the Minnesota questionnaire. An unpaired t‐test, Mann‐Whitney U test or ANCOVA were used for betweengroup analysis, and paired t‐test or Wilcox sign‐rank test for the withingroup analysis. Results: Both groups had similar baseline characteristics and training adherence (HI vs LI; 20 vs 20 subjects; Age: 62±9 vs 59±13 years; Sex: 76% vs 79%male; BMI: 27±58 vs 29±4 kg/m2; LVEF: 35±10 vs 38±6%; Adherence: 33±10 vs 36±10 sessions; p>0.05). There were no adverse events. Both groups had significant within‐group improvements in aerobic and walking capacity (VO2max: LI (n=20) vs HI (n=19), p≤0.010; 6MWT distance: P≤0.007) (Figure 1), but these improvements did not differ between groups (VO2max: P=0.855; 6MWT distance: P=0.854). The LI group improved significantly more in muscle strength than the HI group (dip and leg‐press: P<0.001). Although the LI group significantly improved in the quality of life (Minnesota score reduction: P=0.028), the quality of life did not differ between groups (Minnesota score: P=0.756). Conclusions: Both low‐and high‐intense resistance training are similarly beneficial for improving aerobic and walking capacity in patients with HF. Surprisingly, low‐intense resistance training seems superior to high‐intense training in improving muscle strength.