For Lisa Hanson, a stay-at-home mother in San Francisco, the alarm
that used to rouse her out of sleep most mornings was the sound of her
toddler.
“He wakes up at 5:30 screaming sometimes,” she said. “It
would jolt me awake, and then I’d be miserable and groggy all morning
because I’d be woken up when I’m in my deepest sleep.”
But last
month, Ms. Hanson started using a new program, the Renew SleepClock, an
iPhone app that keeps track of her sleep. Its makers, GEAR4, say that
the app uses radio sensors to detect breathing patterns and movements at
night, then uses that information to wake a person at the lightest
point of sleep, the optimal time to wake up. The theory is that awaking
from light sleep, as opposed to the deep stages of sleep, helps reduce
so-called sleep inertia, the cloud of grogginess and impaired alertness
that makes people desperately want to crawl back into bed. The app also
acts as a sort of sleep adviser, giving Ms. Hanson guidance about the
amount of shut-eye to shoot for and ways to get there.
“Since I’ve
been using it, I do feel better,” Ms. Hanson said. “It’s waking me up
in a more ideal stage of sleep and helping me have that much better of a
day.”
The Renew SleepClock, which costs $199,
is the latest addition to a new generation of smartphone apps designed
to analyze and improve sleep patterns. While experts have warned for
years that gadgets like smartphones are increasingly disrupting sleep by
keeping us connected 24/7, these programs claim to do the opposite. Two
other products that have gained followings are the WakeMate ($59.99), a wristband worn at night that wirelessly transmits data to the user’s smartphone, and the Zeo Sleep Manager-Mobile ($99), which uses a sensor-equipped headband to collect data about the user’s sleep habits.
While
all the apps vary, they generally work by having users pick a window of
time in the morning — typically 20 to 40 minutes long — during which
they would like to get up, then nudging the sleeper awake at the
lightest point of sleep in that window. Sleepers get a score each
morning that factors in the number of hours they slept while adding and
subtracting points for things like disruptions and the percentage of
time spent in the deep, restorative stages of sleep. The programs also
let users keep track of daily habits like caffeine intake, exercise and
meals, among other things, so they can see which habits might be
affecting their sleep.
But while some people swear by these tools,
scientists caution that the claims they make and the advice they dole
out to users may not be very sound.
“I think these are clever
devices, but there’s very limited data on how valuable they are,” said
Dr. David M. Rapoport, the director of the sleep medicine program at New
York University School of Medicine. “They’re a really good way to
capture data. But some of them are giving out recommendations in ways
that just aren’t proven.”
He points out that certain features,
like quantifying sleep and tracking habits, are particularly beneficial
because they identify sleep patterns. “Many people lie to themselves
about how much sleep they’re really getting,” he said. “If it takes an
app to tell you you’re only getting four hours a night and that that’s
why you’re tired, then that’s a good thing.”
But, he says, when an
app instructs you to get eight hours of sleep instead of seven, or to
avoid coffee after 6 p.m. for better sleep, it has gone too far, since
not everyone needs the same amount of sleep or is affected in the same
way by caffeine. “These apps tend to suggest that there’s a right way
you should do things,” he said, “but we cannot make the same
recommendations for everybody.”
Dr. Rapoport also questioned the claim that waking a person from light sleep prevents sleep inertia. While some studies have found evidence of this, others, like one carried out by Harvard researchers and published in The Journal of Sleep Research,
have found it has almost no effect. “It is not clear that
systematically waking people up in light sleep is going to benefit them
or lead to better health,” he said.
Toward
the end of a normal night of rest, the amount of time spent in deep
sleep tends to diminish, so it’s likely that any alarm will wake a
person in light sleep anyway, said Dr. Meir H. Kryger, a professor at
Yale Medical School and the author of a new e-book, “The iGuide to
Sleep.”
“At 6 or 7 in the morning, it’s very likely that a person
will not be in a very deep state of sleep,” he said. “Simply knowing
that means that these devices have a very good chance of working just
because of biology. On the other hand, so does any alarm clock.”
That
is not enough to dissuade faithful users of the programs, like Bart
Epstein, 43, a longtime Zeo user who lives in Arlington, Va. Mr.
Epstein, an executive at Tutor.com, an online tutoring program, says he
has no doubt that the program lives up to its claims. After years of
sleeping poorly, he began using the Zeo, which helped him identify
habits that were keeping him “wired” at night and cutting into his
sleep, like evening exercise, and it forced him to be disciplined about
his bedtime regimen.
“Having all the data that it collects is what
influences me,” he said. “You can lie to yourself and lie to your
spouse, but you can’t lie to the Zeo. It holds you accountable.”
Best of all, he said, he no longer struggles with morning grogginess. “It just doesn’t happen anymore.”
