Effects of an eight-weeks high-speed resistance training program on heart rate variability in community-dwelling independent older adults

Abstract

Objective: This study examined the effects of an eight-week high-speed resistance training (HSRT) program on heart rate variability (HRV) indices (time and frequency domain). Methods: This study included thirty-nine physically independent older adults (age, 68.50±3.52y; BMI, 27.88±4.37 kg/m2). The HSRT program lasted eight weeks, with three sessions per week with 50–60min, each session being comprised of five-six exercises, twothree sets, and six–ten reps/exercise. The intensity was gradually increased after each session in accordance with the movement velocity (>1.3 to 0.75 m/s) representing approximately 20% to 60% of one repetition maximum. Participants executed the exercises rapidly and explosively making all repetitions for each shortening phase (concentric phase) performed as quickly as possible with the lengthening phase of the muscle (eccentric phase) being controlled for 2–3 s. The velocity of the concentric phase in each exercise was monitored through a BEAST™ sensor (Beast Technologies, Brescia, Italy). The heart rate band has been used to assess the variation in sinus origin heartbeat intervals (Polar® H10, Kempele, Finland). Using the Kubios HRV software (Kubios HRV, University of Kuopio, Finland), HRV indices were calculated. The Ethics Committee of the University of Évora approved this study (approval no. 22030). A paired sample t-test (with a cut-off of p< 0.05 for statistical significance) was used for comparing each outcome. Results: After the intervention period, the HRV indices showed significant improvements: on SDNN (∆change=22.42; p=0.028; effect size [ES]=0.206); RMSSD (∆change=28.54; p=0.022; ES=0.213); pNN50% (∆change=52.25; p=0.045; ES=0.238); and on HF (∆change=48.65; p=0.023; ES=0.150). There were no differences on Average RR (∆change=-0.79; p=0.615; ES=-0.055); LF (∆change=-0.44; p=0.974; ES=0.01); and on the Ratio LF/HF (∆change=-1.98; p=0.899; ES=-0.023).Conclusions: The results suggest that the HSRT program is an effective and safe exercise approach to improve several HRV indices, especially SDNN and RMSSD indices.