LAUSR

Objective: To determine whether there is a generalizable relationship between maximal heart rate (HR), age, and injury level in individuals with spinal cord injury (SCI). Methods: Retrospective analysis of aerobic capacity testing (VO2max) of 80 individuals with SCI. Hybrid (arms and legs) functional electrical stimulation (FES) rowing was used as the exercise modality, and multiple objective criteria of a maximal effort had to be achieved so that peak HRs approximated maximal in this population. The relationship between age, maximal HR, and injury level was examined with regression and analysis of covariance, with injury level as a continuous and categorical variable (thoracic vs. cervical). Results: The traditional age-related decline in maximal heart rate is largely preserved (Regression: Maximal HR = 204 – Age, r = -0.63, p < 0.001) in persons with thoracic (n = 42), but not cervical (n = 38), level SCI. There was no effect of sex, motor completeness, or aerobic capacity on this relation in those with thoracic SCI. Individuals with a cervical SCI have a reduced maximal heart rate (136 ± 18 bpm) and does not change with age (p = 0.23). Maximal heart in cervical SCI was not predictable from factors such as age, time since injury, weight, and injury level. Conclusion: Age-predicted maximal heart rate may be suitable for exercise testing and prescription for those with thoracic injuries but should not be used in the cervical spinal cord injured population. This work was supported by NIH grants R01 HL117037 R21 HD088891 and ACL NIDILRR grant 90SI5021. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.