Acute hemodynamic responses during resistance exercise with different intensities in patients with chronic heart failure

Abstract Background Resistance exercise is a key component of exercise programs for patients with chronic heart failure (CHF), aimed to counteracting skeletal muscle myopathy and increasing muscular strength and endurance. Current international guidelines recommend low- to moderate load resistance exercise with a high number of repetitions for patients with CHF, and evidence regarding acute hemodynamic responses to different strength exercise intensities in CHF is limited. Purpose To investigate the acute hemodynamic responses to resistance exercise with either high (HIGH) or moderate (MOD) load in patients with CHF. Methods A total of 13 patients with stable CHF due to reduced left ventricular ejection fraction (LVEF 40%) were recruited from a heart failure outpatient clinic. Three separate test sessions on different days were conducted, where session one included one-repetition maximum (1RM) testing. In a randomized cross-over design, participants performed three sets (S1, S2 and S3) of seated knee-extensions with either MOD load (15RM) or HIGH load (4RM), with one week between protocols. Non-invasive, beat-by-beat hemodynamic responses and cardiac output (CO; L min-1) were measured with a Finapres NOVA (FMS, The Netherlands) and PhysioFlow PF07 Enduro, at rest, during each set and post-exercise. Results Nine men and one woman, age 64 ± 7 years, LVEF 36 ± 6% completed all sessions. One participant dropped out due to knee pain and two for nondisclosed reasons. No adverse events occurred during testing or exercise. Systolic blood pressure (BP; mmHg) was significantly higher during MOD load (15RM) compared with HIGH load (4RM) across all sets as illustrated in Figure 1. (S1: 162±24 vs 139±18, p =.023, S2: 168±31 vs. 142±20, p =.028, S3: 185±43 vs. 141±17, p =.002). Diastolic BP did not differ at S1 (93±15 vs. 79±19, p=.064), but was significantly higher with MOD at S2 and S3 compared to HIGH load (S2: 109±26 vs. 75±17, p =.002, S3: 109±26 vs. 81±17, p =.017). Cardiac output did not differ between loads across sets (repeated measures ANOVA: F(1,9) =2.176, p =.134. Conclusion High-load resistance exercise with 4 repetitions elicited a significantly lower acute hemodynamic responses than MOD load exercise with 15 repetitions in ten patients with CHF due to reduced LVEF. These findings challenge current international guidelines and support the need of further research to optimize resistance exercise for patients with CHF.Figure 1.Systolic blood pressure (SBP)For image description, please refer to the figure legend and surrounding text.