A long, hard bout of exercise can reduce the efficiency of the muscles that move the eyes, and impair vision.
Vigorous workouts can impair eyesight by reducing eye movement
CBC Radio ·
Quirks and Quarks8:30Exercise Can Impair Your Eyesight - 2016/06/04 - Pt. 5
Vigorous workouts certainly make you tired, and it turns out that exercise can compromise the senses as well. Dr. Ben Thompson, associate professor at the University of Waterloo School of Optometry and Vision Science, and his colleagues, tested the ability to move the eyes - an important element in focusing and detecting movement - after a long and intense cycling workout.
They found that eye movement was slowed by nearly ten percent, a significant impairment.
The impairment wasn't related to cognitive function - the brain wasn't tired - but was due to a phenomenon called "central fatigue" that slows and reduces muscle activity - including those muscles that move the eyes - when the body is tired.
- Paper in Scientific Reports - Science news story