Post-exercise heart rate recovery in individuals with spinal cord injury

Abstract

Study design: Prospective comparison of spinal cord injured (SCI) subjects and ambulatory subjects. Objectives: To determine the effects of the presence and level of SCI on heart rate recovery (HRR). Setting: Outpatient SCI center. Methods: HRR was determined in 63 SCI subjects (26 with tetraplegia, 22 with high-level paraplegia, 15 with low-level paraplegia) and 26 ambulatory subjects. To adjust for differences in heart rate reserve between groups (HRpeak minus HRrest), HRR was also 'normalized' to a range of 1 at peak heart rate and to 0 at 8 min, and the shapes of HRR curves were compared. Results: Although absolute HRR was similar between high-and low-level paraplegia, it was significantly more rapid in participants with paraplegia at 2, 5 and 8 min after exercise than in those with tetraplegia (39±14 vs 29±14 b.p.m., Po0.05; 51±14 vs 33±16 b.p.m., Po0.01 and 52±16 vs 36 ± 17 b.p.m., Po0.01, respectively). HRR among ambulatory subjects was more rapid than among those with tetraplegia at all time points in recovery. However, when normalized for heart rate reserve, HRR was significantly more rapid in tetraplegic subjects (Po0.001 vs paraplegia and ambulatory subjects). Conclusion: In SCI, HRR is strongly associated with the peak exercise level and peak heart rate achieved during exercise testing.

Incorporating physical activity into the rehabilitation process after spinal cord injury

“…Any SCI originating at or above these spinal segments contributes to changes in heart rate and blood pressure regulation at rest, a blunted response during exercise, and an impairment in heart rate recovery. 54,55 While the mean resting blood pressure and heart rate is lower among individuals with lesions above T6, these individuals are prone to life-threatening episodes of extreme hypertension (up to 300 mmHg systolic blood pressure), known as autonomic dysreflexia. 56 This sudden increase in blood pressure is typically provoked by noxious stimuli below the level of the lesion, such as bowel and bladder distension, spasms, or bladder catheterization.…”

Association of serum myokines and aerobic exercise training in patients with spinal cord injury: an observational study

“…There is a higher prevalence of cardiovascular diseases in patients with SCI compared to the healthy population [ 3 , 4 ] partly because of decreased physical activity. Muscle weakness and atrophy, and diminished aerobic capacity are common in patients with SCI [ 5 ], while autonomic dysfunction often results in altered heart rate (HR) and blood pressure (BP) response, further heightening cardiovascular risks [ 6 , 7 ].…”

Peak Heart Rates and Sympathetic Function in Tetraplegic Nonathletes and Athletes

“…Conversely, the average peak HR for athletes was >130 bpm, suggest ing that the sympathetic nervous system was a contribut ing factor. Previous literature has consistently demonstrated attenuated peak HR in nonathletic individuals with tetraple gia compared to nonathletic individuals with paraplegia (3,6,13,27) and able-bodied groups (27). The literature on exercise HR in athletic individuals with tetraplegia is incon clusive, with several studies demonstrating attenuated values compared to athletic paraplegics (2,7,20,23,24,29), whereas others report near-nonnal maximal HR responses (33,36,39).…”

“…After a cervical spinal cord injury (SCI), however, there seems to be an atypical HR response to exercise. In nonathletic individuals with tetraplegia, several studies have documented attenuated peak HR responses to exercise (3,6,12,21,25,27), which have been attributed to the loss of descending input to sympathetic preganglionic neurons. Conversely, there have been a few re ports of elevated exercise HR in elite athletes with tetraplegia (33,36,39).…”