Profile of cardiac autonomic modulation of individuals with incomplete cervical spinal cord injury practicing wheelchair rugby

Abstract

Introduction: The spinal cord injury (SCI) is a spinal injury that can occur in any of its segments, including whether or not the nerve roots and spinal cord and can lead to irreversible damage to the individual. However, the degree of impairment of cardiac function associated with neurological injury level. Cervical spinal cord lesions have an impaired autonomic function that contributes to the occurrence of cardiovascular diseases as compared to thoracic or lumbar spinal cord injuries. On the other hand, little is known about autonomic adjustments related to physical exercise for individuals with incomplete cervical spinal cord injury. Objective: The aim of this study was to investigate the profile of the cardiac autonomic modulation in resting individuals with incomplete cervical spinal cord injury (level of the cervical lesion C5 to C8) rugby practitioners in a wheelchair. Methods: The study included 20 male individuals divided into three groups. The control group (CG) consisted of eight subjects (28.3 ± 4.5 years, 178.4 ± 6.5 cm and 82.1 ± 6.8 kg; 27.2 ± 2.5 kg / m2) with intact spinal cord, regularly involved in a strength training program and low intensity aerobic training. Participated in the exercise group (EG) 8 individuals with incomplete cervical spinal cord injury (32.3 ± 4.5 years, 175.1 ± 5.3 cm, 73.6 ± 9.6 kg; BMI 23.8 ± 3, 6 kg / m2) Rugby practitioners in a wheelchair. However, the sedentary group (SG) consisted of four individuals with incomplete cervical spinal cord injury (30.8 ± 5.3 years, 173.4 ± 10.1 cm, 69.7 ± 7.1 kg; BMI of 23, 5 ± 2.9 kg / m2) who did not practice any type of exercise. All subjects were monitored at rest in the sitting posture by electrocardiogram (ECG) and the analysis of heart rate variability was calculated using algorithms based on MATLAB, from the extraction of RR intervals for 10 minutes of continuous recording. Results: The control group (CG) had significantly higher values in RR intervals, the ratio of adjacent RR intervals over 50 ms (pNN50), the number of interval differences of successive NN intervals greater than 50 ms (NN50), the root mean square of successive differences (RMSSD) and high frequency (HF) spectral power in comparison with EG and SG. On the other hand, the RR interval (SDNN) was significantly lower in the control group (CG). Moreover, by effect size statistics (ES) observed a tendency to reduce the LF standard in SG group when compared to the EG group. Conclusion: The practice of physical exercise seems to promote autonomic adjustments in patients with cervical spinal cord injuries incomplete rugby practitioners in a wheelchair.