Bedroom-Invading Smartphones Jumble Body’s Sleep Rhythms
By Jason
Gale Jan 7, 2014 11:28 AM PT
Having trouble sleeping? Check for a glow, inches from the pillow.
Sleep specialist Russell Rosenberg, who was an adviser on the International Bedroom... Read More
Using a
smartphone, tablet or laptop at bedtime may be staving off sleep, according
to Harvard Medical School scientists,
who have found specific wavelengths of light can suppress the slumber-inducing
hormonemelatonin in
the brain.
“We have
biologically shifted ourselves so we can’t fall asleep earlier,” said Charles
A. Czeisler, a professor of sleep medicine at Harvard Medical School. “The
amazing thing is that we are still trying to get up with the chickens.”
The result is
less sleep -- and less time for the body to recover. Routinely getting fewer
than 8 hours of sleep compromises alertness, reaction time, efficiency,
productivity and mood, according to Australia’s Sleep Health Foundation.
In the U.S.
alone, revenue from clinics treating sleep disorders expanded 12 percent
annually from 2008 to 2011, reaching $6 billion, according to IBISWorld.
Drowsy drivers cause 1,550 fatalities in the U.S. a year, the National
Department of Transportation estimates, and insomnia-related accidents in the
workplace cost $31.1 billion annually,
a study last year found. Insufficient sleep has become so prevalent it is now
considered a public health epidemic, according to the U.S. Centers for Disease Control and
Prevention.
“Sleep is in a
battle for our time with work life, social life and family life,” said David
Hillman, a sleep specialist at the Sir Charles Gairdner Hospital in Perth,
Western Australia,
and the chairman of the Sleep Health Foundation. “For a lot of us, it comes off
a poor fourth in that battle.”
Many Gadgets
Regular sleep
disturbances are associated with ailments including obesity, diabetes, heart
disease and cancer, according to Hillman.
Modern
technology isn’t helping.
The National
Sleep Foundation in Arlington, Virginia, commissioned
a survey of 1,500 randomly selected adults in the U.S., Canada, Mexico, Germany, U.K. and
Japan to understand their bedroom environment and its effect on sleep for their
inaugural 2013
International Bedroom Poll. The results, published in September,
showed that more than half of respondents in the U.S., Canada and U.K., and
two-thirds in Japan,
used a computer, laptop or tablet in the hour before bed.
At least
two-thirds of people in all countries surveyed watched TV in the hour before
bed. Only about half said they get a good night’s sleep on work nights.
Body’s Rhythm
“It’s a massive
issue, particularly when you talk about technology,” said Sarah Loughran, a
sleep researcher at the University of Wollongong, south of Sydney. “We’re not
just talking about mobile phones -- but iPads, TVs, laptops. A lot of these
things are in the bedroom.”
Smartphone
manufacturers shipped 724 million of the units globally last year, compared
with 151 million in 2008, according to data compiled by Bloomberg.
While the noisy
ping of a nocturnal e-mail or text message can interrupt sleep,
staring at the gadgets’ screen late at night may be more detrimental, according
to researcher Czeisler, who is also head of sleep medicine atBoston’s Brigham and
Women’s Hospital.
The timing of exposure
to the light-dark
cycle is the most powerful means by which the circadian
clock, the body’s biological time keeper, is synchronized to the 24-hour day,
Czeisler’s research found. He began studying the impact of the circadian rhythm
on sleep in 1972 and has written about 200 scientific papers and review
articles on the subject. He estimates that since the advent of
electricity-powered light, people’s internal sleep triggers have been pushed
back 6 hours.
Night Owls
“It’s our
exposure to artificial light, particularly in the evening between the timing of
sunset and when you normally go to bed, that’s dramatically changed the timing
of our endogenous circadian rhythms,” Czeisler said in an interview.
After being
awake 8 or 10 hours, people start to run out of steam, Czeisler says, prompting
their internal clock to send out a surge of wakefulness that builds until
melatonin is produced to suppress the circadian system and facilitate sleep.
Light exposure in the evening delays the melatonin surge.
Two research
groups in the U.K. and U.S. published studies in 2001 showing that short
wavelengths of light inthe blue part of
the spectrum are
the most active in suppressing
melatonin.
Energy-saving
light-emitting diode lights, known as LED, are especially problematic,
according to Czeisler. LED lights are used in flat-panel televisions, computer
displays and smartphone screens and they are replacingless-efficient
incandescent light bulbs worldwide.
Digital Bedmate
Setting a
technology curfew and using yellow-based lighting in the evening that can be
dimmed and switched off completely by 10:30 p.m. will improve chances of a good
night’s sleep, he said.
“It may be that
gradually lowering the light might be more powerful than just shutting them off
all at once,” Czeisler said. If computers can’t be avoided at night, he
recommends reducing the screen’s blue wavelength light.
Michael Herf,
creator of the Picasa online photo-sharing software bought by Google Inc. in
2004, has come up with an answer: a computer program that automatically alters
the intensity and spectrum of light emitted by the display according to the
time of day. The free software, called f.lux,
has been downloaded 8 million times since Herf and his wife Lorna developed it
in their Los Angeles home in 2008.
Adrenalin Rush
“We put it up
just for some of our friends to try,” Herf, 38, said in a telephone interview.
“This one kind of took off.”
The night-time
setting reduces exposure to the most alerting wavelengths of light by 70 to 90
percent by relying on other colors on the spectrum that interfere less with the
circadian system, Herf said.
In theory,
f.lux should make a difference, according to Czeisler. But it’s no magic
bullet.
There’s another
reason computers, phones and other technology can perturb sleep when used
shortly before bed, says the University of Wollongong’s Loughran. Engaging the
brain with information that’s exciting or provocative can trigger emotional and
other hormonal responses, including the release of adrenalin.
“In
evolutionary terms, as soon as you have something to which you have to respond,
a little blip of adrenalin let’s say, you’re in a mode that might require a
response,” said Susan A. Greenfield, senior research fellow atEngland’s Oxford
University, whose interests include the impact of modern technologies on the
brain. “You have to put yourself in an environment where you can feel relaxed
and safe, where you can go back into your inner world just before you go to
sleep.”
The ideal
bedroom has no distracting bright light or noise, said Greenfield, who is also
a member of the U.K.’s House of Lords.
Sleep
specialist Russell
Rosenberg, who was an adviser on the International Bedroom Poll,
offers simple advice: “Relax, turn off the mobile phone and TV, and create a
more pleasant bed-time routine.”
To contact the
reporter on this story: Jason Gale in Melbourne at j.gale@bloomberg.net
To contact the
editor responsible for this story: Jason Gale at j.gale@bloomberg.net
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