A team of scientists from four countries revealed that physical exercise can tire the eyes as well as the muscles, but a cup of coffee can revive them.
The New Zealand leader of an international study on Thursday in Wellington found the first scientific evidence that rapid eye movements slow down when the body is fatigued.
The study leader, Dr. Nicholas Gant of University of Auckland, said: “The results are important because our eyes must move quickly to capture new information.
“But there’s hope for coffee drinkers because this visual impairment can be prevented by consuming caffeine.”
Gant said in the study that cyclists exercised in a laboratory for three hours, after which their brain’s control of the visual system was tested using specialised eye-tracking cameras.
He said: “It’s remarkable that tiring the legs also slows the eyes.
“This might well be the reason the tired cyclist never saw that bus coming.”
The study leader said an imbalance in neurochemicals caused by strenuous exercise appeared to spread across the brain’s control systems.
He added that a modest dose of caffeine could restore chemical balance, helping signals from the brain to reach the eyes.
Gant said: “The amount of caffeine we gave during exercise was the equivalent of two cups of coffee.
“We saw no effect with a decaffeinated placebo drink.
“Interestingly, the areas of the brain that process visual information are robust to fatigue.
“It’s the pathways that control eye movements that seem to be our weakest link.”
Gant said the team was investigating the effects that psychiatric drugs, used to treat patients with abnormal levels of these neurotransmitters, had on the phenomenon.
Xinhua/NAN.
