The New York Times explains the results:
As it turned out, mental fatigue significantly affected the men’s endurance. They tired about 13 percent faster after the computer test than after watching “Earth.” They also reported that the workout felt far more taxing.
But, interestingly, their maximum contractile force was about the same after each session. Their muscles responded just as robustly to orders from the brain and the attached electrode after the draining mental workout as after the quiet session, even though the brain-fogged volunteers felt as if their muscles were much more exhausted. . .
. . .In simpler terms, exercise simply feels harder when your brain is tired, so you quit earlier, although objectively, your muscles are still somewhat fresh.
It's the first study to explore the subject, but it's an interesting result that deserves a closer look. Check out the link below to read the full study, or check out the New York Times' article about it here.But, interestingly, their maximum contractile force was about the same after each session. Their muscles responded just as robustly to orders from the brain and the attached electrode after the draining mental workout as after the quiet session, even though the brain-fogged volunteers felt as if their muscles were much more exhausted. . .
. . .In simpler terms, exercise simply feels harder when your brain is tired, so you quit earlier, although objectively, your muscles are still somewhat fresh.