Heart rate variability in practitioners of hippotherapy with down syndrome

Abstract

Background: Down syndrome (DS) can lead to motor, cognitive, and socio-affective disorders, and hippotherapy is one therapeutic modality. Alterations in heart rate (HR), defined as heart rate variability (HRV), are modulate by autonomous nervous system. However, many descriptions in the research literature on HRV in practitioners of hippotherapy with DS were not found. The hypothesis of this study is that hippotherapy can generate an increase in HRV in practitioners with DS due to the stimuli offered by the activity and movement of the horse. Purpose: To evaluate heart rate variability in practitioners of hippotherapy with DS before, during and after their practice. Methods: For this study, 6 children with Down syndrome, mean age 12± 1.6 years were recruited. The HR was obtained and calculated by the uptake of RR intervals (R-Ri) of the electrocardiogram, with a cardiofrequencimetre (Polar® RS800CX Heart Rate Monitor – Kempele – Finland), for 5 sessions of hippotherapy for 30 minutes once weekly. HR was collected before, during and after each session. For all statistical analysis, Sigma-Stat® Software version 3.5 was used and a significance level of p value lower than 5% (p< 0.05) were considered. Results: In the data analysis but with no significant results tended to decrease parasympathetic activity at rest, observed by rMSSD indices (square root of the mean squared differences between successive normal intervals) and pNN50 (percentage of adjacent RR intervals differing by duration 50 ms) between the first and fifth sessions. In the frequency domain values of HF (high frequency) have not changed. With respect to sympathetic activity observed at LF index (low frequency), we noted increasing trend. Was also found a significant decrease in parasympathetic activity (p= 0.031), observed by pNN50 index when comparing the behavior of the HR during the first and fifth sessions of hippotherapy in rMSSD index showed a tendency to decrease. In the frequency domain, there were no significant difference in the analyzed components, however, tended to increase in LF and decrease in HF comparing the period during sessions of hippotherapy. Conclusion(s): Through the proposed study it was concluded that during hippotherapy sessions pure threedimensional motion as well as the environment of a hippotherapy centre did not improve HRV in children with DS, so not confirming the hypothesis. Implications: This study showed that the threedimensional movement of the horse alone did not increase heart rate variability in children with DS. Further studies with a larger sample size and longer time should be performed in order to confirm whether HRV can be improved or not by hippotherapy.