Chang, Y. K., Etnier, J. L., & Barella, L. A. (2006). The inverted-U relationship between arousal and fractionated reaction time. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 2149.

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The purpose of this study was to examine the relationship between arousal and cognitive performance using fractionated reaction time to identify the effects on central and peripheral components. Males (N = 16) served as Ss. Heart rate reserve (HRR) was determined by recording baseline HR and maximal HR during a ramped exercise protocol on a bicycle ergometer. Heart rate reserve was used as the index of arousal. On Day 2, Ss performed the reaction time task at eight different levels of arousal (20%, 30%, 40%, 50%, 60%, 60%, 70%, 80%, or 90% HRR). The order of presentation of the arousal levels was randomized using a Latin-Squares design with the limitation that the higher intensities (70%, 80%, and 90%) were never performed back-to-back and were not performed during the first trial block. At each intensity level, the resistance level on the bicycle ergometer was determined using information from the ramped exercise protocol to get the S's HR to the target level. Ss were asked to perform 10 simple reaction time trials once they reached target HR for each level of arousal.

A significant linear trend for movement time was revealed. For both movement and motor time, latencies generally decreased with increasing arousal levels. There was no significant difference in pre-motor time as a function of arousal.

Implication. Arousal induced by different exercise intensities influences the peripheral components of simple reaction time and does not affect the central components. In addition, the relationship tends to supports the drive theory instead of the inverted-U hypothesis. It was concluded that arousal influences simple reaction time through its impact on motor function rather than having an impact on cognition per se, and that this relationship is linear in nature.

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