Reaction time to peripheral visual stimuli during exercise under hypoxia

Abstract

The purpose of this study was to test the hypothesis that decrease in cerebral oxygenation compromises an individual's ability to respond to peripheral visual stimuli during exercise. We measured the simple reaction time (RT) to peripheral visual stimuli at rest and during and after cycling at three different workloads [40%, 60%, and 80% peak oxygen uptake (VO2)] under either normoxia [inspired fraction of oxygen (FIO2)=0.21] or normobaric hypoxia (FIO2=0.16). Peripheral visual stimuli were presented at 10 degrees to either the right or the left of the midpoint of the eyes. Cerebral oxygenation was monitored during the RT measurement over the right frontal cortex with near-infrared spectroscopy. We used the premotor component of RT (premotor time) to assess effects of exercise on the central process. The premotor time was significantly longer during exercise at 80% peak VO2 (normoxia: 214.2+/-33.0 ms, hypoxia: 221.5+/-30.1 ms) relative to that at rest (normoxia: 201.0+/-27.2 ms, hypoxia: 202.9+/-29.7 ms) (P<0.01). Under normoxia, cerebral oxygenation gradually increased up to 60% peak VO2 and then decreased to the resting level at 80% peak VO2. Under hypoxia, cerebral oxygenation progressively decreased as exercise workload increased. We found a strong correlation between increase in premotor time and decrease in cerebral oxygenation (r2=0.89, P<0.01), suggesting that increase in premotor time during exercise is associated with decrease in cerebral oxygenation. Accordingly, exercise at high altitude may compromise visual perceptual performance.

Does cerebral oxygenation affect cognitive function during exercise?

“…The decrease in adjusted P ET CO 2 indicates that hyperventilation occurred during exercise at 80% peak _ VO 2 . Hyperventilation leads to constriction of the arterioles in the brain (Nybo and Rasmussen 2007;Querido and Sheel 2007) and may decrease cerebral oxygenation (Ando et al 2010;Bhambhani et al 2007;Secher et al 2008). Hence, together with arterial de-saturation during strenuous exercise (Nielsen et al 1999), hyperventilation is likely to contribute to the decrease in cerebral oxygenation we observed during strenuous exercise.…”

“…When the brain is activated during exercise, an increase in cerebral oxygen supply is required to match the enhanced level of neuronal metabolism (Secher et al 2008). However, hyperventilation induced by strenuous exercise may lead to decrease in cerebral oxygenation (Ando et al 2010;Bhambhani et al 2007;Secher et al 2008). Thus, in the present study, we expected that if cerebral oxygenation is associated with cognitive function during exercise, a decrease in cerebral oxygenation may impair cognitive function during strenuous exercise.…”

Effect of Various Eye Exercise Techniques along with Pranayama on Visual Reaction Time: A Case Control Study

“…A study carried out in 10 male participants to examine whether cerebral oxygenation affects an individual's ability to respond to peripheral visual stimuli during exercise suggest that decrease in cerebral oxygenation, has a potential to compromise visual perceptual performance [9].…”

Sightings edited by John W. Severinghaus

“…Hypoxic Exercise Delays Response to Peripheral Visual Stimuli Ando, Yamada and Kokubu (2010) report that a decrease in cerebral oxygenation produced by exercise at 80% of VO 2max while breathing 16% O 2 compromises an individual's ability to respond to peripheral visual stimuli (p < 0.01). This effect was not present at 21% O 2 .…”