Effects of a sixteen-week High-Speed Resistance Training program on heart rate variability indexes in community-dwelling independent older adults

Abstract

Objective: This study examined the effects of a sixteen-week high-speed resistance training (HSRT) program on heart rate variability (HRV) indexes (time, frequency, and non-linear domains). Methods: Seventy-nine independent older adults were divided into an intervention group (IG) [N=40, age, 68.50±3.54 years; body mass index (BMI), 27.88±4.37 kg/m²] and a control group (CG) [N=39, age, 72.08±5.89 years, BMI, 26.53±3.04 kg/m²]. The IG participated in supervised HSRT sessions three times weekly, with 5–6 exercises, 2–3 sets, and 6–10 repetitions, lasting 60–70 minutes. Intensity increased progressively based on movement velocity (>1.3 to 0.75 m/s), representing approximately 10% to 65% of one repetition maximum. Exercises were performed rapidly during the concentric phase, monitored via a BEAST™ sensor (Beast Technologies, Brescia, Italy), followed by a controlled 2–3 second eccentric phase. The CG maintained daily activities, tracked by the IPAQ Questionnaire. HRV was assessed using a heart rate band (Polar® H10, Kempele, Finland) and analyzed with Kubios HRV software (Kubios HRV, University of Kuopio, Finland). The study was approved by the Ethics Committee of the University of Évora (approval no. 22030). Results: After HSRT program, ANCOVA results showed significant improvements in total variability, expressed by mean RR in favour of the IG (p=0.049, η²p=0.050), and decreases in general heart rate (HR) variables in favour of the IG, such as mean HR (p=0.030, η²p=0.060), min HR (p=0.043, η²p=0.053) and max HR (p=0.050, η²p=0.049). Additionally, significant increases in stress index (p=0.002, dunb=0.52), SampEn (p=0.035, dunb=0.38, and DFA α1 (p=0.039, dunb=0.38) were obtained in the CG after intervention. Conclusions: This clinical trial highlights the significant potential of the HSRT program to improve overall variability and cause favorable modifications in older persons' parasympathetic indexes.