Effects of dynamic resistance training on heart rate variability in healthy older women

Twenty healthy women aged between 65 and 74 years, trained three times a week, for 16 weeks, on a cycle ergometer, to determine the effects of dynamic resistance training on heart rate variability (HRV). Subjects were allocated to two training groups, high (HI, n = 10) and low (LO, n = 10) intensity. The HI group performed eight sets of 8 revolutions at 80%, of the maximum resistance to complete 2 pedal revolutions (2RM); the LO group performed eight sets of 16 pedal revolutions at 40% of 2RM. Subjects were tested twice before, as control period (-4 weeks and 0 weeks) and once after training (16 weeks) for HRV, maximum voluntary contraction (MVC) of knee extensors and peak power (P-p) of lower limbs by jumping on a force platform. HRV was measured using time and frequency domain parameters. Two-way ANOVA for repeated measures was performed on all variables (P < 0.05). Results showed no differences between training groups. Following training HRV was not modified, while MVC and P-p significantly increased. The two proposed forms of dynamic resistance training were appropriate to improve muscle power and strength in elderly females without affecting HRV. More research should verify the effects of an isometric and more prolonged training stimulus on HRV in older subjects.