Fighting Sleep: Losing Battle
Only recently have scientists come to understand this phenomenon called "mental fatigue," Robert Stickgold, PhD, a cognitive neuroscientist and psychiatrist at Harvard Medical School, tells WebMD.
With Harvard students as his test subjects, Stickgold has teased out some interesting conclusions.
Students volunteered to perform an hourlong, repetitive task that even Stickgold admits was "sort of tiring." They did it four times a day: at 9 a.m., noon, 4 p.m., and 7 p.m. "Lo and behold, they got worse and worse and worse" as the day wore on, he says.
He then tried a few things to ferret out just what "cured" mental fatigue.
- He changed the task a bit, and that helped. The students' "work" improved vastly -- performance went right back up to morning levels.
- A half-hour afternoon nap also helped. Their performance didn't get better, but it didn't get any worse.
- Even better: After an hour-long afternoon nap, students "bopped back to where they were in the morning" -- but only those who got rapid eye movement (REM) sleep, which helps with memory, learning, thinking.
- What worked best: A 90-minute nap created a "whopping improvement." Those students performed as well as "fresh" students with a full night's sleep, because they all got REM sleep.
The need for sleep -- as with all other biological drives -- involves a disconnect between what the body really needs and what it feels like it needs, Stickgold explains.
"In a funny way, it's as if only a small part of your brain needs sleep," Stickgold tells WebMD. "When this small part becomes saturated -- your inbox is full -- it will signal you."
Say you've been studying all night, and think you're burned out. Then someone shows up with tickets to the midnight show, and you bounce right up and go. You won't actually feel exhausted until 1:30 a.m. when you get home.
When we fight mental fatigue, that's the disconnect we're dealing with, he explains. "There are two ways to deal with burnout -- switch to a different task, or get some sleep," says Stickgold.