Effects of brisk walking on autonomic nervous system reactivation in nursing home residents. Additional effects of transcutaneous vagus nerve stimulation

Abstract

It is well established that physical activity reduces the physiological effects of ageing. Among them, is the decrease of the autonomic nervous system (ANS) activity, which is associated with the increase of cardiovascular events and morbidities. It has been shown that high intensity cycle training can enhance the ANS activity by 30% in people with the age of 70. However, such trainings were done by old athletes, used to train at intensities that could not be tolerated by sedentary old people, such as nursing home residents. Furthermore, vagus nerve stimulation (VNS) is a novel technique that could potentialize the training effects on the ANS by reducing the parasympathetic activity decrease that occurs after an exhausting exercise. Therefore, we aim to compare the effects of a 9-month brisk walking training (1 time a week or 3 times a week) on the ANS of nursing home residents. Also, we wish to measure the effects of post exercise VNS stimulation on the ANS activity. One hundred and fifty 60-year-old subjects and older will be recruited within the ten nursing homes of La Mutualité française de la Loire, France, and will be randomized into 5 groups: – G1: one brisk walking session a week; – G2: one brisk walking session a week + VNS; – G3: three brisk walking sessions a week; – G4: three brisk walking sessions a week + VNS; – G5: control group (no training or VNS). Testing procedure will occur at the inclusion and after 3 months, 6 months and 9 months of training. The primary outcome measure is the heart rate variability (SDNN value) measured by 24 hours Holter ECG and baroreflex. We expect an increase of the ANS activity, particularly of the parasympathetic arm, with a dose–response relationship through training. The increase would be higher for the group of subjects having trained 3 times per week and who will receive VNS. Expected conclusion brisk walking training could enhance the ANS tone and could improve the parasympathetic/sympathetic balance in nursing home elderly. This effect would be potentialized by VNS.