Facts of Life
Facts of Life:
Issue Briefings for Health Reporters
Vol. 9, No. 1
January 2004
A Wake-Up Call on the Value of Sleep
The Issue
The Facts
Insufficient Sleep or Excess Waking?
The Ripple Effects of Tossing and Turning
Expert Sources
References
The Issue:
Too many
people get too little sleep. For some, the problem is insomnia. Researchers
call it DIMS — difficulty initiating or maintaining sleep. Much insomnia
is short-term, a result of transient anxieties. But medical, psychological
and social stresses cause insomnia lasting months or years.
Out of Breath
Another
leading cause of sleeplessness is obstructive sleep apnea, in which sleeping
people stop breathing for 20 or 30 seconds several times an hour. In sleep
apnea, the soft tissues of the neck and throat temporarily close off the
air passage. Risk factors for OSA include being overweight, male and over
40. These brief interruptions in breathing decrease blood oxygen levels
and cause recurrent wakefulness, which leads to disruption in mood, neurocognitive
changes and daytime sleepiness. Snoring and frequent sleep interruptions
also disturb bed partners of those with sleep apnea. Other circadian rhythm
disturbances occur with jet lag, shift work and the body’s changes
at adolescence.
A few people get
too much sleep. Narcolepsy is a rare neurologic condition producing excessive
sleepiness and loss of muscular control. It is likely due to the absence of a
protein in the brain. Restless leg syndrome is another sleep disorder — a
need to move the legs, accompanied by muscle ache or “creepy-crawly” sensation.
Drug treatments may help.
[11]
The Facts:
- Each year, 200,000
auto accidents are blamed on sleepy drivers. Fatality rates in sleep-related
accidents (1.4 percent) are almost as great as those
involving alcohol (2.1 percent). [1, 11, 15]
- Most sleep-related crashes involve driving off the
road faster than 50 miles an hour and occur between midnight and 7
a.m. or 1 p.m. and 3
p.m. More than half of these drivers were under age 25, and most were
alone. [1, 11]
- Sleep shortages and irregular sleep cycles may affect
health care, because medical professionals in hospitals must be awake
and functioning at times
that are in conflict with normal sleep patterns and circadian physiology.
[2]
- The costs of insomnia were estimated at $13.9 billion
in 1995, because of impaired memory and decreased economic output
due to poor concentration
and impaired ability to accomplish daily tasks. The condition also
leads to lessened enjoyment of personal relationships. About 20
percent of urban
employees work outside the hours of 8 a.m. to 5 p.m. [3, 16]
- Caffeine helps overcome sleep inertia, which
includes cognitive performance impairment and grogginess. Sleep-deprived
U.S. Navy SEALs improved their
marksmanship in training exercises when given 200-300 mg of caffeine.[4,
5]
- Risk factors for sleep apnea, caused by soft
tissues of the throat blocking the airway, include obesity,
snoring and high blood pressure. The condition
occurs in as many as 4 percent of men and 2 percent of women
age 30 to 60. Even more meet at least one criterion for sleep
apnea, including a
breathing stoppage for at least 10 seconds more than five times
an hour.[6]
- A study of National Football League players
estimated that 14 percent of all team members and 34 percent
of linemen may have sleep apnea, although
they are young and otherwise healthy. [7]
- Sleep
apnea is known to cause high blood pressure and is also
associated with ischemic heart disease,
heart failure,
stroke and cardiac arrhythmias.
It is also associated with glucose intolerance and insulin
resistance, precursors of Type 2 diabetes. Treatment
for sleep apnea includes weight
loss, sleeping on one’s side and avoiding alcohol
or sedatives. [8, 9]
- The modest sleep
loss that results from going to bed even an hour later
than usual can
compromise children’s alertness
and brain functioning.
- Experts
say the best solution for sleepiness is to get enough sleep.
Accidents caused
by drowsiness could be reduced if sleepy drivers
stopped for a short nap and had a cup or two of coffee.
[10]
Insufficient
Sleep or Excess Waking?
Like that half-full or half-empty glass, sleep may be
in the drowsy eye of the beholder.
A recent study by members of the Division of Sleep and Chronobiology
in the psychiatry department at the University of Pennsylvania School
of Medicine says the problem of sleeplessness is not so much the lack
of sleep as the staying awake too long. [13]
The researchers restricted sleep among healthy volunteers to four
or six hours a night for two weeks. These seemingly minor sleep deprivations
do not have minor effects.
Sustained night after night, they affect alertness, working memory
and cognitive function and produce the same outcomes on psychological
tests as one to two days of total sleep deprivation.
That means that excess wakefulness rather than cumulative loss of
sleep is the main cause of reduced neurocognitive function, say the
researchers.
They estimated that the critical waking period beyond which these
lapses occur is 15.84 hours, meaning the average sleep needed per night
is 8.16 hours.
“The present data suggest that this temporal regulation of sleep
serves to protect human neurobehavioral functions from degradation
due to excessive wakefulness within and between circadian cycles,” they
say.
Despite these objective results, the subjects tended to minimize their
own sense of sleepiness.
“The
lack of reports of intense feelings of sleepiness during chronic
sleep restriction may explain why sleep restriction is widely
practiced — people have the subjective impression they have adapted
to it because they do not feel particularly sleepy,” the Penn
researchers say.
The
Ripple Effects of Tossing and Turning
Lack
of sleep is a problem for more than the individual staring at the
ceiling in the middle of the night.
“Pervasive sleep deprivation and untreated and mistreated sleep
disorders remain arguably the biggest health problem in America,” says
William C. Dement, M.D., Ph.D., of Stanford University, who has studied
sleep for half a century. “The costs of a sleepy society include
lost lives, lost income, disability, lost educational opportunities,
accidents and family dysfunction.”
.
.
Expert
Sources:
David F. Dinges, Ph.D.
U. of Pa. School of Medicine
(215) 898-9989
dinges@mail.med.upen.edu
www.med.upenn.edu/ins/faculty/dinges.htm
William C. Dement, M.D., Ph.D.
Stanford University
(650) 723-6320
dement@stanford.edu
Alan Schwartz, M.D.
Johns Hopkins Bayview Med. Ctr.
(410) 550-1850
schwartz@mail.jhmi.edu
Also see:
National Center on
Sleep Disorders Research
www.nhlbi.nih.gov/about/ncsdr/index.htm
See a past issue of Facts of Life on this topic:
www.cfah.org/factsoflife/vol3no3.cfm
References
1. Pack, A.I.,
Pack, A.M., Rodgman, E. et al. Characteristics of crashes attributed
to the driver
having fallen asleep. Accident Analysis & Prevention.
1995 Dec; 27(6):769-75.
2. Buysse, D.J., Barzansky, B., Dinges, D. et al. Sleep, fatigue,
and medical training: setting an agenda for optimal learning and patient
care. Sleep. 2003 Mar 15;26(2):218-25.
3. Rajaratnam, S.M., and Arendt, J. Health in a 24-h society. Lancet.
2001 Sep 22; 358(9286):999-1005.
4. Van Dongen, H.P., Price, N.J., Mullington, J.M. et al. Caffeine
eliminates psychomotor vigilance deficits from sleep inertia. Sleep.
2001 Nov 1; 24(7):813-9.
5. Tharion, W.J., Shukitt-Hale, B., Lieberman, H.R.. Caffeine effects
on marksmanship during high-stress military training with 72 hour sleep
deprivation. Aviation, Space and Environmental Medicine. 2003 Apr;.74(4):309-14.
6. Flemons, W.W.. Clinical practice: Obstructive sleep apnea. New
England Journal of Medicine. 2002 Aug 15;.347(7):498-504.
7. George, C.F., Kab, V., Levy, A.M. Increased prevalence of sleep-disordered
breathing among professional football players. New England Journal
of Medicine. 2003 Jan 23 ;348(4):367-8.
8. Wolk, R., Kara, T., Somers, V.K. Sleep-disordered breathing and
cardiovascular disease. Circulation. 2003 Jul 8; 108(1):9-12.
9. Punjabi, N.M., Sorkin, J.D., Katzel, L.I. et al. Sleep-disordered
breathing and insulin resistance in middle-aged and overweight men.
American Journal of Respiratory and Critical Care Medicine. 2002 Mar
1; 165(5):677-82.
10. National Highway Traffic Safety Administration, Drowsy Driving
and Automobile Crashes: Report and Recommendations. April 1998. http://www.nhlbi.nih.gov/health/prof/sleep/drsy_drv.pdf
11. Earley, C.J.. Clinical practice. Restless legs syndrome. New
England Journal of Medicine. 2003 May 22; 348(21):2103-9.
12. Powell, N.B., Schechtman, K.B., Riley, R.W., et al. The road to
danger: the comparative risks of driving while sleepy. Laryngoscope.
2001 May; 111(5):887-93.
13. Van Dongen, H.P., Maislin, G., Mullington, J.M., Dinges, D.F.
The cumulative cost of additional wakefulness: dose-response effects
on neurobehavioral functions and sleep physiology from chronic sleep
restriction and total sleep deprivation. Sleep. 2003 Mar 15; 26(2):117-26.
14. Sadeh, A., Gruber, R. and Raviv, A. The effects of sleep restriction
and extension on school-age children: what a difference an hour makes.
Child Development 2003 Mar-Apr; 74(2):444-55.
15. Roehrs, T. and Roth, T. Sleep, sleepiness, and alcohol use. National
Institute on Alcohol Abuse and Alcoholism. http://www.niaaa.nih.gov/publications/arh25-2/101-109.htm.
16. Roth, T., Ancoli-Israel, S. Daytime consequences and correlates
of insomnia in the United States: results of the 1991 National Sleep
Foundation Survey. II. Sleep. 1999 May 1; 22 Suppl 2:S354-8.
The Center for the Advancement
of Health is an independent nonprofit organization that promotes
greater recognition of how psychological, social, behavioral,
economic and
environmental factors influence health and illness. The Center advocates the highest
quality research and communicates it to the medical community and the public. The
fundamental aim of the Center is to translate into policy and practice the growing body of
evidence that can lead to the improvement and maintenance of the health of individuals and
the public. The Center was founded by the John D. and Catherine T. MacArthur Foundation
and the Nathan Cummings Foundation, which continue to provide core funding. Funding for
this series was provided by the Robert Wood Johnson Foundation.
For Information Contact:
Kristina Campbell
Editor, Health Behavior News Service
Center for the Advancement of Health
2000 Florida Ave., NW, Suite 210
Washington, DC 20009
p. 202.387.2829 / f. 202.387-2857
press@cfah.org
http://www.cfah.org
© Copyright 2003, Center for the Advancement of Health
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