BioEd Online Sleep and Human Performance David F. Dinges, PhD Team 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

BioEd 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.

BioEd Online Complex Animals Sleep and Need Sleep to Survive BioEd Online

BioEd Online 24h blood draws 24 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

BioEd 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

BioEd Online There are Differences Among People in the Duration of Sleep Needed Studies indicate adolescents (ages years) generally need more sleep per day ( 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

BioEd 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

BioEd Online Brain Imaging Studies Schema of PET acquisition process Sites 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

BioEd Online Van Dongen, H. P. A., Maislin, G., Mullington, J. M. & Dinges, D. F. (2003). Normal alert performance Performance errors equal to being awake hours Performance errors equal to being awake hours Zone of impaired performance Repeated days of sleep restriction Lapses of attention during performance (slow reaction times) 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

BioEd 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 Time of Day Number of Crashes :00 2:004:006:008:00 10:0012:0014:00 16:0018:0020:0022:00 Escalating occurrence of accidents across the night shift from 0:00hr to 8:00hr