This probably won’t get you excited for your next session at the gym.
Turns out that exercise not only makes your muscles tired, but wears down your eyes as well.
When you’re training vigorously, your tiring muscles run out of fuel. Once they’re gassed, waste products in the body begin to build. An imbalance in the body’s chemical messengers, known as ‘central fatigue’, impedes the central nervous system from directing muscle movements efficiently. This could affect other motor systems not involved in the workout – like the eyes, for example.
To find out for sure, researchers provided 11 participants a carbohydrate solution either with a moderate dose of caffeine (which is known to stimulate the nervous system), or a placebo sans caffeine.
After three hours of intense cycling, the scientists tested the cyclists with eye-tracking cameras. They found the exercise reduced the speed of rapid-eye movements by 8%, struggling to capture new visual information.
The group that had the caffeine-infused solution didn’t suffer any eye setbacks, with some cyclists showing improved eye movement speed.
So it may be a good idea to drink some coffee before working out – or get someone to drive you home if you don’t.