The Role of Autonomic Function on Sport Performance in Athletes With Spinal Cord Injury

Abstract

Devastating paralysis, autonomic dysfunction, and abnormal cardiovascular control present significant hemodynamic challenges to individuals with spinal cord injury (SCI), especially during exercise. In general, resting arterial pressure after SCI is lower than with able-bodied individuals and is commonly associated with persistent orthostatic intolerance along with transient episodes of life-threatening hypertension, known as "autonomic dysreflexia." During exercise, the loss of central and reflexive cardiovascular control attenuates maximal heart rate and impairs blood pressure regulation and blood redistribution, which ultimately reduces venous return, stroke volume, and cardiac output. Thermoregulation also is severely compromised in high-lesion SCI, a problem that is compounded when competing in hot and humid conditions. There is some evidence that enhancing venous return via lower body positive pressure or abdominal binding improves exercise performance, as do cooling strategies. Athletes with SCI also have been documented to self-induce autonomic dysreflexia before competition with a view of increasing blood pressure and improving their performance, a technique known as "boosting." For health safety reasons, boosting is officially banned by the International Paralympics Committee. This article addresses the complex issue of how the autonomic nervous system affects sports performance in athletes with SCI, with a specific focus on the potential debilitating effects of deranged cardiovascular control.

Comparison of Different Blood Lactate Threshold Concepts for Constant Load Performance Prediction in Spinal Cord Injured Handcyclists

“…Bland–Altman plots also display a considerable range of peak HR responses (Figure 2). A possible explanation could lie in the SCI that may result in a delayed systemic adaptation to increased physiological demands (Krassioukov and West, 2014). However, this was considered and compensated in a prolonged warm-up phase.…”

Acute Effects of Caffeine on Heart Rate Variability, Blood Pressure and Tidal Volume in Paraplegic and Tetraplegic Compared to Able-Bodied Individuals: A Randomized, Blinded Trial

“…It is already well-known, that a spinal cord injury implies some crucial physiological adaptations due to the injury. Such consequences include not only bone mass, active muscle mass or the inability to use the limbs, but also gastrointestinal transition time, bladder, bowel and sexual functions as well as cardiovascular capacity and the activation of the autonomous nervous system [ 1 – 6 ]. As the sympathetic nerves leave the spine between Th1 and L2, loss of function highly depends on the level and severity of the lesion.…”

Boosting in Elite Athletes with Spinal Cord Injury: A Critical Review of Physiology and Testing Procedures

“…The thermoregulatory response to exercise in individuals with SCI has been reviewed elsewhere [56]. For an extensive review of the autonomic response to exercise, see Krassioukov and West [2].…”

“…For a practice to be deemed illegal it must meet two of the following criteria: (1) has the potential to enhance or enhances sport performance; (2) represents an actual or potential risk to the athlete; and/or (3) is against the spirit of the sport [61].…”

“…Another issue is that many athletes with SCI experience dysfunction of the autonomic nervous system (ANS) [1], which has major implications on athletic performance [2]. For individuals with cervical or high thoracic SCI, the diminished, or absence of, supraspinal control over spinal autonomic circuits results in altered vasomotor, sudomotor, and cardiac function that typically present as a blunted heart rate (HR) and blood pressure (BP) response to exercise [3][4][5][6][7].…”