Alterations in Heart rate Variability in Blind Patients

Abstract Blindness affect the daily life activities and the causes and prevalence are different worldwide. This study aimed to investigate the pattern of the autonomic nervous system modulation on the heart in blind and normal vision subjects submitted acutely to low vision. Normal vision (NV) subjects (N = 32) and blind patients (N = 24) were submitted to HRV analysis during resting, intervention and recovery periods. Intervention consisted of handling objects, short walking, and cognitive activities performed with pedagogic games while using sleeping masks. No difference was observed in indexes in the time and frequency domain, and in the geometric indexes comparing blind and NV subjected to acute low vision during resting and recovery. Nevertheless, during intervention, RMSSD, pNN50, and SD1were found lower in blind than in NV subjects. Therefore, blind patients showed similar HRV at resting or upon possible stressful challenges compared to NV subjects acutely subjected to low vision, indicating absence of differences in the cardiovascular risk between groups. In addition, blind patients show a smaller reduction in parasympathetic modulation on the heart during possible stressful challenges than NV individuals submitted to low vision, which is likely an important physiological adaptation for an adequate function of the cardiovascular system in blindness.