Effect of sub-maximal physical fatigue on auditory and visual reaction time in healthy adults: repeated measures design

Abstract

BackgroundAuditory reaction time (ART) and visual reaction time (VRT) are critical for patients with stroke, especially during balance training. According to the research, most patients with stroke are fatigued at sub-maximal levels during their stroke rehabilitation. Sub-maximal physical fatigue may affect ART and VRT and impede stroke rehabilitation. Hence, it is important to study the effect of submaximal physical fatigue on ART and VRT. A pilot study on healthy adults paves the way for further research on stroke rehabilitation. The purpose of this research is to find out if submaximal physical fatigue affects ART and VRT in healthy adults. In addition, this study also determines if ART and VRT recover to baseline after 15 min of rest post-fatigue session. Furthermore, the goal is to determine whether sub-maximal physical fatigue has a greater effect on ART or VRT.MethodsA repeated measures within-subject design was used in the study. Eighteen healthy participants (median age 24 years) completed two sessions of a sub-maximal fatigue protocol on a cycle ergometer until they reached a rating of perceived exertion (RPE) of 15 on a scale of 6–20. Two different fatigue sessions were conducted (one to study the effects of fatigue on ART and the other for VRT). ART or VRT was measured on computer software before (PRE), immediately after (POST-0), and 15 min after (POST-15) the sub-maximal physical fatigue protocol.ResultsThe value of median ART increased significantly from PRE to POST-0 (P = 0.002) and it decreased significantly at POST-15 (P = 0.010). Similarly, the value of mean VRT increased from PRE to POST-0 (P = 0.001) before decreasing significantly at POST-15 (P = 0.001). There was no significant difference between the effects of submaximal fatigue on ART and VRT (P = 0.156).ConclusionDue to submaximal physical fatigue, ART and VRT were slower, but they returned to baseline after 15 min of rest. Submaximal physical fatigue had an equal impact on ART and VRT. As balance training requires quicker ART and VRT for optimal outcomes, it may be better if the physiotherapists consider a 15-min rest period between the exercise and balance training in patients with stroke.