Comparison of the Short-Term Effects of Horse Trekking and Exercising with a Riding Simulator on Autonomic Nervous Activity

The aim of this study was to determine whether sympathetic and/or parasympathetic nervous activities were altered after horse trekking (HT) and exercise with a riding simulator (RS). Changes in heart rate variability (HRV), salivary alpha-amylase (sAA) activity, and psychological states were compared between HT and RS. In HT, 26 university students with no disability rode on a horse with a leader along a trekking course for 30 min. As a control, the same participants rode on a AS in a room for 30 min. HRV and saliva were sampled at 120 and 60 min before and at 15, 60, and 120 min after each exercise. The values 120 min before exercise were used as baseline values, and the percentage of baseline values of each period were analyzed. Psychological tests were also conducted before and after the exercises. Two-way and one-way repeated measures ANOVA and Tukey's multiple comparison tests were used for statistical analysis. The high frequency component of HRV (HF), an index of parasympathetic nervous activity, was increased at 120 min after HT (194%) compared with that recorded 60 min before HT (113%). On the other hand, HF was increased at 60 min after RS (146%) compared with that recorded 60 min before AS (117%). There were neither main effects nor interactions with regard to LF/HF and sAA activity, indices of sympathetic nervous activity. There were interactions (exercise x time) with regard to vigor and anxiety. These findings suggest that merely 30 min of HT greatly increased the rider's parasympathetic nervous activity and vigor and lowered their anxiety, while AS also had a moderate effect on parasympathetic nervous activity. A new kind of therapeutic riding could be developed using HT or a RS.