Sleep Copyright © 2001 by Harcourt, Inc. All Sleeping and waking rhythms • Biological rhythms in animals: – Annual cycles – Monthly cycles – 24-hour cycles (circadian) • Levels of consciousness vary throughout a 24-hour period – Ninety-minute cycles (stages of sleep) Copyright © 2001 by Harcourt, Inc. All Sleep Facts Sleep is an interplay between: •Internal biological clock (circadian rhythms), and •External factors (e.g., light/dark cycles, sociocultural factors, stressors) Copyright © 2001 by Harcourt, Inc. All Physiological assessment of sleep Copyright © 2001 by Harcourt, Inc. All Stages of Sleep Copyright © 2001 by Harcourt, Inc. All Sleep architecture Copyright © 2001 by Harcourt, Inc. All Dreams • Function of Dreams? – Freud – “Daytime residue” – Activation-Synthesis Hypothesis • “What’s in a dream?” (video Sci Amer #14)) Copyright © 2001 by Harcourt, Inc. All Sleepless in Swannanoa (Sleep Deprivation and its Effects) Copyright © 2001 by Harcourt, Inc. All How much do we need and why do we need it? Reference: NSF Copyright © 2001 by Harcourt, Inc. All Sleep as restorative Sleeping brain is active: Regulates immune and endocrine functions essential for general health Copyright © 2001 by Harcourt, Inc. All Sleep as a necessity Main Point: Sleep has a strong impact on our waking life: from mood to alertness to learning to motor skills to health, etc.… Yet, we treat sleep as a luxury rather than as a necessity. Copyright © 2001 by Harcourt, Inc. All Sleep Facts • Adult sleep need is usually 7-9 hours (Homeostatic “set point”?) • Impairment in performance occurs with as little as one or two hours less per night. • Sleep debt from restricting sleep to 5-6 hours a night accumulates with time. Copyright © 2001 by Harcourt, Inc. All Sleep’s demand… Sleep is mediated by central nervous system. With accumulating sleep debt, we show the signs of impending sleep … Copyright © 2001 by Harcourt, Inc. All Chronically Sleep Deprived... The average American sleeps fewer than 7 hours 37% of adults say they are so tired during the day it interferes with daily activities 74% of adults experience symptoms of a sleep disorder a few nights a week or more Just one in five adolescents gets an optimal nine hours of sleep on school nights (High school seniors – 6.9 hrs/nt) College students – 6.1 hrs/nt NSF Sleep in America Poll Copyright © 2001 by Harcourt, Inc. All Are You Sleep Deprived? 1. I need an alarm clock in order to wake up at the appropriate time. 2. It’s a struggle for me to get out of bed in the morning. 3. Weekday mornings I hit the snooze bar several times to get more sleep. 4. I feel tired, irritable, and stressed out during the week. 5. I have trouble concentrating and remembering. 6. I feel slow with critical thinking, problem solving, and being creative. 7. I often fall asleep watching TV. 8. I often fall asleep in meetings or lectures or in warm rooms. 9. I often fall asleep within five minutes of getting into bed. 10. I often feel drowsy while driving. 11. I often sleep extra hours on weekend mornings. 12. I often need a nap to get through the day. Copyright © 2001 by Harcourt, Inc. All Sleep Deprivation Are WWC students sleep deprived? Sample: 202 students* • 6.9 hrs/nt • 29% get 6 hours or less • 2 out of 3 get 7 hours or less • 25% feel either “very” or “extremely” tired in the morning Copyright © 2001 by Harcourt, Inc. All *Swoap (2008) WWC Survey, Consequences of Sleep Loss Behavioral/Mood Physiological Sleepiness / Microsleeps Psychomotor Impairment Accidents Decreased Work Productivity Reduced Quality of Life Mood Effects Deficits in Learning and Memory Lack of Awareness/Concentration Substance Use / Abuse Immuno-compromise Insulin Resistance Increase in stress hormones Blunted Arousal Response (EEG) Copyright © 2001 by Harcourt, Inc. All Effects on health: Institute of Medicine Report An Unmet Public Health Problem “The cumulative effects of sleep loss and sleep disorders represent an underrecognized public health problem and have been associated with a wide range of health consequences including an increased risk of hypertension, diabetes, obesity, depression, heart attack, and stroke. Almost 20 percent of all serious car crash injuries in the general population are associated with driver sleepiness. Hundreds of billions of dollars a year are spent on direct medical costs related to sleep disorders such as doctor visits, hospital services, prescriptions, and over-thecounter medications.” Copyright © 2001 by Harcourt, Inc. All Effects on health Dr. Jan Born-- Univ. of Luebeck, Germany found that people who sleep only 6 hours: •Have lowered their resistance to viral infection by 50% •Produce half the flu fighting antibodies after a flu shot Copyright © 2001 by Harcourt, Inc. All Effects on workers Up to 70 million working Americans suffer from sleep deprivation. The cost to businesses is enormous • increased health care costs • sleep-deprived workers are responsible for causing a 250% increase in serious work errors, many work-related accidents, and increases in absenteeism and presenteeism American Institute for Preventive Medicine Copyright © 2001 by Harcourt, Inc. All Effects on driving (Jan, 2008) – Three Florida A&M University students were involved in a fatal car accident off Interstate 10. The 5:30 a.m. accident on Jan. 6 left two of the students injured and one dead. Freshmen Antoine Gordon, 18.; Carlos Wilkins, 18; and Cornell Wedge, 19, were driving back to campus from winter break when Wilkins fell asleep at the wheel. Wilkins said once Wedge, who sat in the passenger seat, noticed Wilkins was asleep he tried to wake him. However, with the semi truck that rode beside them as well as the constant nudge from Wedge, Wilkins was startled and lost control of the Ford Escort. The car veered off the road into a ravine and hit three trees. Gordon, who was asleep in the backseat with no seatbelt, died on impact. Prior to the accident, Gordon's mother said she sensed the group was tired and insisted they pull over and rest before continuing to campus. Instead of taking a break, the three students decided to continue driving. Copyright © 2001 by Harcourt, Inc. All “Drowsy Driving” – Physiological effects (underaroused cortex) – Poor judgment – Driving 60 mph… how far do you travel during a microsleep (4 sec)? Conservative estimate: 100,000 accidents/yr; 1500+ deaths/yr Majority occur between 12 & 6 a.m. Copyright © 2001 by Harcourt, Inc. All Hours of Sleep and Equivalent Blood Alcohol Level for Sedative Effects BrEC, %* 0.190 0.15 0.10 0.05 0.095 0.102 4 2 0.045 Legal Intoxication† 0.20 0.00 6 0 Sleep time (hours in bed) *Approximate breath ethanol concentration (BrEC) at peak; †Above 0.05% for legal intoxication in many states. N=32 healthy subjects without prior sleep deprivation and with 85% sleep efficiency. Sleep loss group (n=12) was tested in all 4 conditions, with 3 to 7 days of recovery time between tests, and compared with ethanol group (n=20). Roehrs T, et al. Sleep. 2003;26:981-985. Copyright © 2001 by Harcourt, Inc. All NSF campaign against Drowsy Driving Copyright © 2001 by Harcourt, Inc. All Substance use and sleep deprivation The relationship between substance abuse and sleep disturbance is bidirectional. • Not only does substance abuse lead to sleep disturbances, but sleep disturbance can lead to substance abuse. • One way that sleep disturbance may create a pathway for substance abuse is that the combinations of sleep disturbance, excessive daytime sleepiness, and poor outcomes, can lead to self-medication. Students may use stimulants to increase daytime alertness and alcohol and marijuana to decrease depressive mood and sleep problems. Copyright © 2001 by Harcourt, Inc. All Bootzin & Stevens, 2005 Effects on learning Considerable scientific evidence supports a role of sleep in memory and learning. Numerous investigators have reported sleep-dependent learning across sensory, skill, and motor memory domains. Both animal and human studies especially implicate sleep as important for the process of memory consolidation following initial learning. Distinct memory processes may be related to specific sleep states (i.e., REM) such that sleep disruption negatively impacts learning. Copyright © 2001 by Harcourt, Inc. All Effects on cognitive performance • Reduced ability to process, concentrate & remember • Reduced ability to communicate 1/3/08 Fatigue Factor Gives Equal Time to Candidates (NYTimes) – Mike Huckabee offered his “apologies” last week over the killing of former Prime Minister Benazir Bhutto of Pakistan. (He meant “sympathies,” his campaign clarified.) Sleeping much? “Obviously, I could use more than I am getting,” said Mr. Huckabee, who is down to about four hours a night. – “Senator Barack Obama blamed fatigue for his drastically overstating the death toll from tornadoes in Kansas in May. He said 10,000 people died. (12 did.) Copyright © 2001 by Harcourt, Inc. All Effects on cognitive performance • Poor decision skills and increased risktaking • Reduced ability for complex problemsolving (study on REM- vs. NREM-deprived students) • Reduced vigilance and increased errors (study on Marines in training) Copyright © 2001 by Harcourt, Inc. All What to do?? • Ingest stimulants? (e.g., Caffeine, Provigil – the “cognitive enhancers”) Copyright © 2001 by Harcourt, Inc. All What to do?? Take a pill for “perfect” sleep or find the “perfect” mattress Copyright © 2001 by Harcourt, Inc. All What to do, really… – When we don’t get enough sleep, our bodies DEMAND it. Listen to that demand… – Get out of debt… “sleep debt” – Sleep hygiene • Fitness, nutrition, nicotine, caffeine, alcohol, “worry time,” establish routine cycles (don’t change drastically on weekends) • What about naps? Copyright © 2001 by Harcourt, Inc. All Sleep Disorders • 40 million Americans • Insomnia – recurring problems in falling or staying asleep • Narcolepsy – uncontrollable sleep attacks – sufferer may lapse directly into REM sleep, often at inopportune times Copyright © 2001 by Harcourt, Inc. All Sleep Disorders • Sleep Apnea – characterized by temporary cessations of breathing during sleep and consequent momentary reawakenings • Night Terrors – high arousal-appearance of being terrified – usually in Stage 4, within 2-3 hours of falling asleep Copyright © 2001 by Harcourt, Inc. All Sleep Disorders • REM Sleep Behavior Disorder (video) Copyright © 2001 by Harcourt, Inc. All