Comparison of autonomic heart control at rest in physically active individuals with and without spinal cord injury

Abstract

Introduction: Spinal cord injury (SCI) is a debilitating neurological condition that, according to anatomical height, affects the stability of cardiac autonomic control. In general, physically active individuals have better cardiac autonomic control as a
chronic adaptation induced by exercise. However, in the SC scenario, it is not yet clear whether physical exercise would also provide such adaptations. Objective: The aim of the study was to purchase cardiac autonomic control at rest from physically active
individuals with and without SCI. Methods: Sectional study in which physically active individuals with SCI (paraplegics - n = 10 and quadriplegics - n = 09) and without SCI (n = 09) were submitted to an assessment of heart rate variability (HRV) at rest, in a
sitting position, for electrocardiogram (ECG). The acquisition of the signals was made during 10 minutes, the last 5 being considered for the analysis. The HRV indices were calculated in the frequency and time domains using the Kubios software. The comparison between groups was made using non-parametric statistical procedures (α = 5%). Results: The paraplegia group was older than the group without SCI (p = 0.007). The groups were similar in relation to HRV indices in the time domain: SDNN, in ms (p = 0.327); rMSSD, in ms (p = 0.301) and average RR interval, in ms (p = 0.568). In the frequency domain, the groups were also similar for the LF indices, in ms2 (p = 0.312) and in u.n (p = 0.825); HF, in ms2 (p = 0.456) and in u.n (p = 0.825) and LF / HF (p = 0.825). The only difference observed was in the VLF index, in ms2 in which the paraplegia group had lower median values compared to the group without SCI (p
= 0.018). Conclusion: The absence of differences in HRV indices between groups suggests an adaptive characteristic of individuals with paraplegia and quadriplegia as a function of physical exercise.