Catecholamines Response of High Performance Wheelchair Athletes at Rest and During Exercise with Autonomic Dysreflexia

Abstract

Autonomic dysreflexia presents a special situation in high-lesion spinal cord injury, however, intentionally or self-induced autonomic dysreflexia directly before or during competition to increase performance, so called 'boosting', is also being reported. In order to examine the influence of autonomic dysreflexia on plasma catecholamines, cardiocirculatory and metabolic parameters, 6 spinal cord injured wheelchair athletes with high-level lesions underwent wheelchair ergometry without (ST1) and with (ST2) autonomic dysreflexia. At the point of exhaustion significantly higher values for norepinephrine and epinephrine were observed in ST2 than in ST1. During autonomic dysreflexia a significantly higher peak performance (77.5 vs. 72.5 watt), higher peak heart rate (161 vs. 149 x min(-1)), and peak oxygen consumption (1.96 vs. 1.85 l x min(-1)), with comparable peak lactate (7.11 vs. 7.00 mmol x l(-1)) were reached on average. The blood pressure values in ST2 were partially hypertensive and higher than in ST1. In conclusion, autonomic dysreflexia, as a sympathetic spinal reflex, leads to a higher release of catecholamines during exercise. This results in higher peak performance, peak heart rate, peak oxygen consumption, and higher blood pressure values. The peak lactate, as an indicator of the anaerobic lactate metabolism, was unchanged. However, autonomic dysreflexia presents an unpredictable risk, caused predominantly by hypertensive blood pressure values, for high-lesion spinal cord injured persons at rest and more so during exercise; it is seen as a prohibited manipulation by the doping guidelines of the International Paralympic Committee.

Performance diagnostics in handbiking during competition

“…Although the athlete had a lesion-induced neuronally and hormonally inhibited positive chronotropic impact on the sympathetic neuronal system, his average heart frequency of 136 bpm was relatively high (the origin of sympathetic innervation of the heart is located between Th 1 und Th 4 ). 9 In this case, the average heart frequency is an important indicator of a rather high work load. As the lactate accumulation is limited due to the lesion level and the reduced effective muscle mass, 5 mean lactate values of 3.4 mmol/l, recorded at three points of time, speak for an intensive work load, too.…”

“…(Maximum lactate concentration on a previous stage test was 6.1 mmol/l). The average oxygen uptake of 1584 ml/min revealed a lower value compared to persons with a low-and mid-lesion level spinal cord injury (Th [5][6][7][8][9][10][11][12] according to the classification by 10 ), but this result can also be attributed to the reduced positive impact of the sympathicus. 9 In handbiking, the extent of energy consumption, which is a very important factor from the point of view of preventive medicine, is highly encouraging.…”

“…The average oxygen uptake of 1584 ml/min revealed a lower value compared to persons with a low-and mid-lesion level spinal cord injury (Th [5][6][7][8][9][10][11][12] according to the classification by 10 ), but this result can also be attributed to the reduced positive impact of the sympathicus. 9 In handbiking, the extent of energy consumption, which is a very important factor from the point of view of preventive medicine, is highly encouraging. 4,11,12 The American College of Sports Medicine (ACSM), for example, recommends an additional energy consumption by endurance sport on 3 days/week with a moderate intensity to prevent arteriosclerotic diseases.…”

The individual relationship between heart rate and oxygen uptake in people with a tetraplegia during exercise

“…18 AD may result in an uncontrolled elevation of BP, and during exercise, this may lead to sudden changes in HR and eventually a higher HR peak and VO 2peak . 19 Apart from the disturbed sympathetic innervation, persons with TP have a low physical capacity as a consequence of the low active muscle mass and inactivity of the venous muscle pump. Because of the disturbed sympathetic innervation and the low physical capacity, it is questionable whether HR can be used for monitoring exercise intensity in persons with a high-level PP or TP.…”

Lesión medular y ejercicio físico: revisión desde una perspectiva deportiva

“…Este procedimiento, que se conoce comúnmente como "boosting", que podría traducirse del inglés como "amplificador de presión" o "efecto turbo", aumenta la FC, la captación de oxígeno y la concentración de catecolaminas en sangre (Schmid et al, 2001;Wheeler et al, 1994), produciendo mejoras en el rendimiento deportivo valoradas en un 10 %, en hombres, competidores de maratón en silla de ruedas (Bhambhani, 2002). Asimismo, la percepción del esfuerzo realizado resulta más baja, mientras acusan un aumento del estado de alerta y de la agresividad (Wheeler et al, 1994).…”