Embed Size (px)
Citation preview
BioEd Online
Sleep and Human
Performance
David F. Dinges, PhDTeam Leader
Neurobehavioral and Psychosocial Factors National
Space Biomedical Research Institute
Professor of Psychiatry Division of Sleep and
Chronobiology Department of Psychiatry
University of Pennsylvania School of Medicine
BioEd Online
www.BioEdOnline.orgBioEd Online
Sunset over North America Feb.1, 2003
Melatonin receptor binding on the human suprachiasmatic nucleus (SCN)
(courtesy of David Weaver)
SCN
Cross section image shows the light-sensitive melatonin receptor cells on the biological “clock” (red areas) in
the human brain.
24-hour cycle
Human Genetic Molecular “Clock”
BioEd Online
Sleep-wake cycles are controlled by a genetic 24-hour “clock” in our
brains that influences our performance, moods and physiological functions.
www.BioEdOnline.orgBioEd Online
Complex Animals Sleep and Need Sleep to Survive
BioEd Online
www.BioEdOnline.orgBioEd Online
24h blood draws24 hr core body
temperature
Volunteer Live Laboratory Sleep Studies
The effects of sleep deprivation have been investigated scientifically by having healthy young adults go without sleep while undergoing continuous physiological monitoring of brain activity and performance.
Courtesy of David F. Dinges, PhD
BioEd Online
24 hr blood draws
24 hr behavioral monitoring
24 hr EEG, EOG, ECG, EMG
www.BioEdOnline.orgBioEd Online
24 hr Infrared
Monitoring
24 hr Performance Testing Computer test batteries are used to evaluate volunteer brain functioning.
Sleep Performance Laboratory
Courtesy of David F. Dinges, PhD
BioEd Online
www.BioEdOnline.orgBioEd Online
There are Differences Among People in the Duration of Sleep Needed
Studies indicate adolescents (ages 13-21 years) generally need more sleep per day (8.5-10 hours) than do most adults (7-8 hours).
Adolescents are vulnerable to sleep loss by having poor sleep habits due to staying up too late studying, playing or socializing.
Excessive daytime sleepiness is a problem in adolescents; it often reflects a sleep debt resulting from inadequate sleep duration at night.
Adolescents have sleep disorders that further limit their sleep time. These can include the following (among others).
Delayed sleep phase syndrome = unable to fall asleep until early morning and unable to wake up until late morning
Insomnia = difficulty falling asleep or staying asleep Obstructive sleep apnea = cessation of breathing during sleep
BioEd Online
www.BioEdOnline.orgBioEd Online
Dinges, D. F. (1986)
Sleep Latency = Sleep Propensity = Sleepiness
Latencies from wake to stage 1 non-REM sleep (Aw-S1) and to stage 2 non REM sleep (Aw-S2), and from stage 2 to slow wave sleep (S2-SWS) become exponentially shorter as the need for sleep increases.
BioEd Online
www.BioEdOnline.orgBioEd Online
Brain Imaging Studies
Schema of PET acquisition processSites of reduced brain activity
resulting from sleep deprivation, as revealed by
PET imaging.
PET imaging can provide information about metabolic activity in the brain.
prefrontal cortex
thalamus
posterior parietal cortex
www.BioEdOnline.orgBioEd Online
Van Dongen, H. P. A., Maislin, G., Mullington, J. M. & Dinges, D. F. (2003).
Normal alert performance
Performance errors equal to being awake 24-40 hours
Performance errors equal to being awake 40-64 hours
Zone of impaired
performance
Repeated days of sleep restriction
Lapse
s of
att
enti
on
duri
ng p
erf
orm
ance
(sl
ow
react
ion
tim
es)
Repeated nights of sleep restricted to less than 8 hours
time in bed (TIB) resulted in cumulative cognitive deficits that were equal to those found after 1 and 2 nights
without any sleep.
“Sleep debt” results from sleeping less than needed to be fully alert and at your best performance.
BioEd Online
www.BioEdOnline.orgBioEd Online
Pack, A. I., Pack, A. M., Rodgman, E., Cucchiara, A., Dinges, D. F., & Schwab, C. W. (1995). Adapted 2007
Risk of Drowsy Driving Crashes in Adolescents/Young Adults
BioEd Online
0
50
100
150
200
250
300
350
400
450
Time of Day
Num
ber o
f C
rashes
Time of Day
Nu
mb
er
of
Cra
sh
es
100
150
200
50
250
300
350
400
450
0
0:0
02:0
04:0
06:0
08:0
010:0
012:0
014:0
016:0
018:0
020:0
022:0
0
Escalating occurrence of accidents across the night shift from 0:00hr to 8:00hr
