Abstract
Purpose :
Prolonged strenuous exercise can decrease the velocity of saccades. This kinematic impairment of eye movements suggests that central oculomotor control is susceptible to exercise-induced fatigue. In this meta-analysis, we combine 42,474 saccades measured during fatigue-inducing exercise, and sedentary rest, to predict the extent to which human physical characteristics influence the fatigability of saccadic eye movements .
Methods :
35 participants (14 male, 21 female) were included in a logistic regression analysis. Exercise involved 180 min of stationary cycling at an exercise intensity equivalent to 60% of maximal aerobic capacity. Aerobic capacity is a measure of cardiorespiratory fitness that can be used to precisely match exercise intensity across participants. Pro- and anti-saccades were measured before and after experimental treatments using infrared occulography within a comprehensive battery of visual system tests.
Results :
Despite the matched relative exercise intensity, aerobic fitness was a statistically significant factor in determining saccade velocity, with a 7% reduction in odds for slower saccades for every 1 ml/kg/min increase in aerobic capacity. Non-oculomotor perceptual tasks were unaffected by exercise. A higher proportion of females exhibited slower eye movements after exercise, with the odds ratio predicting females to be 2.3 times more likely than males to experience slower saccades. Other potentially influential factors, including age, body mass index, dietary caffeine intake, and the types of saccade analysed (pro or anti-saccades), had no significant influence upon the statistical model.
Conclusions :
Individuals with low aerobic fitness are more susceptible exercise-induced oculomotor fatigue. The protective effect of improved fitness appears unrelated to cardiorespiratory adaptations, as relative cardiometabolic demands of exercise were equivalent for all participants. Exercise training may improve the resilience of the brain-based components of oculomotor fatigue. Females appear more disposed to exercise-induced oculomotor fatigue. This effect was unrelated to sex differences in body mass and height. Mechanisms underpinning variation in oculomotor fatigability due to physical fitness and sex require further investigation.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.