Abstract
Context: Autonomic dysreflexia (AD), characterised by a transient increase in systolic
blood pressure (BP), is experienced by individuals with spinal cord injury (SCI) and can
be purposefully induced (‘boosting’) to counteract autonomic dysfunction that impairs
cardiovascular responses to exercise. Herein, we demonstrate the impact of
unintentional boosting observed during cardiopulmonary exercise testing (CPET) in an
inactive male with SCI (C5, motor-complete). Findings: On two separate occasions the
individual performed a standard arm-crank CPET (1-min stages, 7W increase in
resistance) following by a longer CPET (4-min stages, 12W increase in resistance),
both to volitional exhaustion. The second CPET was performed to confirm the accuracy
of exercise intensity prescription and verify peak exercise parameters. Immediately
following the second CPET on the initial visit, the individual reported symptoms of AD,
verified as a 58mmHg increase in systolic BP from baseline. Relative to the first CPET,
performed only 35 minutes earlier, there were pronounced differences in peak exercise responses. In comparison to the longer CPET performed on the second visit without a concomitant episode of AD (thereby controlling for the type of CPET protocol
administered), peak exercise outcomes were considerably elevated: power output
(19W), oxygen uptake (3.61 ml.kg.-1min-1), ventilation (11.4 L.min-1) and heart
rate (9 b.min-1). Conclusion/Clinical Relevance: This case raises important
considerations around the nuances of CPET in this population. In individuals
susceptible to BP instability, the physiologically boosted state may explain a significant
proportion of the variance in peak aerobic capacity and should be closely monitored before and after clinical CPET.
blood pressure (BP), is experienced by individuals with spinal cord injury (SCI) and can
be purposefully induced (‘boosting’) to counteract autonomic dysfunction that impairs
cardiovascular responses to exercise. Herein, we demonstrate the impact of
unintentional boosting observed during cardiopulmonary exercise testing (CPET) in an
inactive male with SCI (C5, motor-complete). Findings: On two separate occasions the
individual performed a standard arm-crank CPET (1-min stages, 7W increase in
resistance) following by a longer CPET (4-min stages, 12W increase in resistance),
both to volitional exhaustion. The second CPET was performed to confirm the accuracy
of exercise intensity prescription and verify peak exercise parameters. Immediately
following the second CPET on the initial visit, the individual reported symptoms of AD,
verified as a 58mmHg increase in systolic BP from baseline. Relative to the first CPET,
performed only 35 minutes earlier, there were pronounced differences in peak exercise responses. In comparison to the longer CPET performed on the second visit without a concomitant episode of AD (thereby controlling for the type of CPET protocol
administered), peak exercise outcomes were considerably elevated: power output
(19W), oxygen uptake (3.61 ml.kg.-1min-1), ventilation (11.4 L.min-1) and heart
rate (9 b.min-1). Conclusion/Clinical Relevance: This case raises important
considerations around the nuances of CPET in this population. In individuals
susceptible to BP instability, the physiologically boosted state may explain a significant
proportion of the variance in peak aerobic capacity and should be closely monitored before and after clinical CPET.
| Original language | English |
|---|---|
| Journal | Journal of Spinal Cord Medicine |
| Publication status | Accepted/In press - 23 Dec 2020 |