2020 Volume 8 Pages 11-27
Aim: This study compared changes in autonomic nerve indicators of high frequency (HF) norm and low frequency (LF)/HF ratio among young and elderly participants before and after standing: when actively standing up, when passively standing up with assistance from others, and when standing up with the aid of a lower-limb power-assisted robot (HAL) from a sitting position on a 40 cm-high chair. Methods: The sample comprised 11 healthy young and 14 elderly individuals aged 20-26 years (mean: 22.5±2.2) and 66-77 years (mean: 70.3±3.5), participants were asked to stand up under 3 different conditions and electrocardiogram measurements and blood pressure were measured. Results and Conclusion: Young and elderly participants showed decreased RRI across all conditions and no significant differences in average blood pressure were found before or after standing. Decreased HF norm and increased LF/HF ratio showed excitation of the sympathetic nerves, increasing blood pressure to compensate for and prevent orthostatic hypotension. Such compensation was likely not due to age although significant differences were found in the coefficient variance of RRI between young and elderly participants. HAL standing proved to have a marginal impact on young and elderly persons’ circulatory dynamics.
