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.

Study design: Cross-sectional analysis of a convenience sample of locally recruited participants, including both patients and volunteers. Objectives: To determine whether there is an association between plasma homocysteine and hypertension in persons with spinal cord injury (SCI). Setting: Spinal Cord Injury Service of the Veterans Affairs Palo Alto Medical Center (California, United States of America). Methods: The incidence of hypertension, dyslipidemia, insulin resistance, and the presence of metabolic syndrome were determined in 168 individuals with SCI (mean age 50.2712.8 years). Fasting lipids, insulin, glucose, plasma homocysteine, and anthropometric data was gathered for each subject. Results: Blood pressure values (Po0.001) and mean arterial pressure (Po0.05) increased with higher plasma homocysteine levels. Homocysteine values were also significantly greater among individuals with hypertension compared with those who were normotensive or prehypertensive (Po0.0001). There was an inverse relationship between plasma homocysteine levels and glomerular filtration rate and effective renal plasma flow (Po0.05). Conclusions: Plasma homocysteine levels are elevated in persons with SCI who have hypertension and inversely related to renal function, which suggests that renal dysfunction may be a link between homocysteine and hypertension in persons with SCI.