Purpose: Lowered substrate availability and exercise-induced fatigue are known to impair motor performance. It is currently unclear, however, whether the human visual system is also susceptible to this type of functional impairment. The aim of this study was to assess the extent to which the neural control of eye movements and cortical processing of visual information are susceptible to exercise-induced fatigue and hypoglycemia. This study examined visual performance after prolonged exercise and energy depletion. Methods: Within a double-blind, randomized, cross-over design, 9 male cyclists (mean age 30.5 y and VO2max 61 ml/kg) consumed either placebo (fatigue + hypoglycemia condition) or carbohydrate (fatigue alone condition) solutions every 15 min during a 180 min cycling protocol. Exercise was performed after a 14h overnight fast at an intensity equivalent to 60% VO2max. Visual acuity, binocular function, global motion perception and saccadic eye moments, were assessed using an established social attention eye movement paradigm, which was employed before and after the exercise protocol. Eye movements were recorded using an infra-red eye-tracker. Heart rate and perceived exertion were recorded throughout the protocol and venous blood samples were collected at routine intervals for assessment of plasma glucose and serum insulin. Results: Fatigue alone or fatigue and hypoglycemia did not reduce visual acuity, binocular visual function, global motion perception or the effects of social attention on the latency of eye movements. There was, however, a significant reduction in the velocity (F[1,8] = 18.4, p = 0.003) and accuracy (F[1,8] = 34.7, p < 0.001) of saccadic eye movements for both the fatigue alone and fatigue + hypoglycemia conditions. Conclusion: Neural processing of visual information is robust to exercise-induced fatigue and hypoglycemia, however ocular motor control is susceptible to the effects of prolonged and depleting exercise. Exercise-induced perturbations in homeostasis may impair the function of cortical areas governing
© Copyright 2012 17th Annual Congress of the European College of Sport Science (ECSS), Bruges, 4. -7. July 2012. Veröffentlicht von Vrije Universiteit Brussel. Alle Rechte vorbehalten.