 Greg Belenky, M.D., and Hans Van Dongen of the Sleep Research Institute
at WSU Spokane use handheld devices to check the sleep habits and
reaction times of their sleep study volunteers.
No Snooze, You Lose
Shifting focus from molecules to people brings a different kind
of answer to the question of why we sleep: we just don’t function
well if we don’t.
The exact amount we need changes through our lifetime—babies
sleep a lot more, and old folks tend to sleep less—but the standard
advice to get eight hours of sleep a night is right for most
adults. Some oft-heard advice about naps, though, isn’t right—for
instance, that a short daytime nap will make up for a short night’s
sleep.
“That’s baloney,” says Greg Belenky. “A five-minute snooze in a
meeting takes the edge off the sleepiness, but it doesn’t improve
your performance.” If you only slept six hours in the past 24,
you’ll need two hours of nap time to top yourself off. So if you’re
going to rely on naps to stay rested, he says, do it right. “Nap
early, nap often.”
He should know. Belenky studied the effects of sleep deprivation
for the Army for more than two decades. He came to WSU Spokane in
2004 from the Walter Reed Army Institute of Research, where he
directed the Division of Neuroscience.
Other than using military style for clock times (“See you at
ten-hundred hours”), Belenky seems more like a cheerful academic
than a career Army officer. He laces his conversation with wordplay
and movie references. The Treasure of the Sierra Madre and
Night Shift come up in the first 15 minutes of our talk.
Belenky says the Army’s interest in sleep science centers on one
thing: performance. Will a soldier in the field make the right
decision and be able to follow through on it when called on to do
so?
His research showed that you don’t need to lose an entire
night’s sleep to be impaired. Even modest sleep deprivation over a
period of days—dropping from eight hours to seven hours of sleep
per night—significantly hinders mental performance, reaction time,
and judgment.
Belenky studies sleep and performance both in the field and in
the lab. In field studies, volunteers wear a wristwatch-like device
called an actigraph that records when the wearer is asleep
(motionless) and when he’s awake. The actigraph allows the wearer,
or a supervisor, to keep track of how much sleep the individual has
had. In the lab, Belenky restricts the sleep of volunteers by
different amounts for periods of up to two weeks. In both kinds of
tests, he measures the subjects’ performance on a psychomotor
vigilance task test, or PVT.
He hands me a Palm Pilot to let me try his latest version of the
PVT. A bull’s eye image appears on the screen. I push a response
button. The screen shows my reaction time—0.27 second. This goes on
for about a minute, the target image showing up at odd intervals.
My average score at the end is 0.302 second, a bit slower than a
well-rested person with PVT experience.
I note that three of my scores were much higher than the
others—over 0.4 second—and say it felt like they came after a
moment of inattention.
“Exactly!” Belenky says. He notes that Hans Van Dongen has shown
that the number of “PVT lapses”—response times of half a second or
longer—shoots up after just two nights of six hours’ time in
bed.
Half a second doesn’t sound like much, but if you’re driving 75
miles per hour, in half a second you’ll travel 55 feet—far enough
to cross two lanes of traffic and the median.
Add to that the finding that up to one-third of us are
chronically sleep deprived, and you get an even scarier picture. It
may not matter if you got a full quota of sleep this week. Odds are
the driver behind you, the one beside you, or the one in the
oncoming lane, didn’t.
“For years the Federal Motor Carrier Safety Administration said,
‘Oh, only about 5 percent of accidents are fatigue-related’” says
Belenky, “—but another 35 percent are from inattention!”
In fact, sleep shortage played a role, often the primary role,
in almost every accidental disaster in recent memory—the meltdown
at Chernobyl and the wreck of the Exxon Valdez, for
example.
Belenky says people who do well with substantially less than
eight hours of sleep per night are rare. And a person’s own
assessment of his or her fitness “is next to useless,” he says.
“Some people perform poorly and think they’re doing great, while
others perform fine and think they’re doing poorly.”
He says most tales of legendary figures who “never” sleep can’t
be believed. General Maxwell Thurman, who helped rebuild the Army
after the Vietnam era, “was rumored never to sleep,” says
Belenky.
“He was unmarried, sort of a military monk. A real fire-eater.
His staff all had to be there before he got there, and only could
leave after he left, and he had a driver. So basically he could
spend every waking minute on Army business and still get seven or
eight hours of sack time. To his staff it looked quite different.
That’s where the idea came from that the Old Man never slept. But
that simply wasn’t true.”
Belenky and Van Dongen are getting ready to start studies of
sleep and performance in the new “sleep suite” at the Spokane
campus. Equipped with private sleeping rooms and a shared kitchen
and living room, the sleep suite allows observers to track the
brain activity, sleep cycles, and PVT performance of four live-in
volunteers at a time. Also in the works are field studies with
medical residents at Spokane-area hospitals and Spokane police
officers, among others.
Page
1
2
3
Continued
|
