To regular coffee or tea drinkers, it probably comes as no surprise that caffeine can perk up tired eyes. That’s probably why as many as 80% of people at any social event will accept an offer of coffee or tea. But a new study from researchers at the University of Auckland in New Zealand has confirmed the benefits of caffeine for eye movement in a very particular way.
Dr. Nicholas Gant and his team initially set out to determine whether the kind of physical fatigue produced by intense physical exercise, such as cycling, had an effect on rapid eye movement ability in the same way as it did with other motor functions, such as limb movement.
To find out, they recruited 11 well-trained cyclists to pedal on stationary bikes for three hours and subsequently measured their rapid eye movement functions with a head-fixed eye-tracking system. The results were conclusive.
“This is the first study to show impaired control of eye movements following fatiguing exercise,” the study’s authors commented alongside the publication of their findings in the journal Scientific Reports. “Prolonged use of the skeletal motor system influences the function of the oculomotor system, implicating a possible role of central fatigue.”
In other words, “These results are important because our eyes must move quickly to capture new information,” Dr. Gant 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 good news is that the study also found that ingesting caffeine during the exercise — a drink equivalent to the caffeine found in two cups of coffee, in the experiment settings — counteracted these eye-slowing effects. There was no such effect found with a caffeine-less placebo drink.
“There’s hope for coffee drinkers because this visual impairment can be prevented by consuming caffeine,” Dr. Gant said. So before your next ride, be sure to drink up — for your sight’s sake!