SLEEP 4: Sleep Your Health Today, 6th edition

Sleep Circadian rhythm: internal daily 24-hour cycle of waking and sleeping Most adults need about 8–9 hours of sleep each night A typical college student sleeps only 6–7 hours a night on week nights

Sleep and Your Health Sleep is a period of rest and recovery from the demands of wakefulness It can be described as a state of unconsciousness or partial consciousness from which a person can be roused by stimulation We spend about a third of our lives sleeping

Health Effects of Sleep Sleep is strongly associated with overall health and quality of life Restoration and growth take place during the deepest stages of sleep Natural immune system moderators increase during sleep and promote resistance to viral infections A lack of sleep can lead to a breakdown in the body’s health-promoting processes Short sleep: less than 7 hours; increases risk of negative health outcomes Long sleep: 10 hours or more; has not been found to have negative health consequences

Health Effects of Sleep Sleep deprivation and other sleep disorders are associated with serious physical and mental health conditions ( See p. 79, text) Slowed reaction time High blood pressure, heart disease, stroke Suppressed immune system Overweight and obesity Breast cancer Diabetes Dementia, Alzheimer’s, multiple sclerosis, Parkinson’s disease

Sleep Deprivation Sleep deprivation is the lack of sufficient time asleep, a condition that impairs physical, emotional, and cognitive functioning Effects all domains of functioning Emotional effects, including heightened irritability and difficulty handling stress Reduced motivation Reaction time, coordination, and judgment Memory impairments

Sleep Deprivation Chronic sleep deprivation damages brain cells and impairs debris removal, accelerating brain aging Sleep debt is the difference between the amount of sleep attained and the amount of sleep needed to maintain alert wakefulness during the daytime, when the amount attained is less than the amount needed Can’t be made up for with extra sleep on weekends May disrupt sleep structure Prescription stimulants are not a healthy solution

What Makes You Sleep? Circadian rhythms are maintained by the suprachiasmic nuclei (SCN) in the brain Internal “biological clock” that controls body temperature and levels of alertness and activity SCN signal the release of hormones, including signaling the pineal gland to release melatonin, which increases relaxation and sleepiness, and the pituitary gland to release growth hormone during sleep to help repair damaged tissues External environmental cues such as light are also important

The Structure of Sleep The brain cycles into two main states of sleep: Non-rapid eye movement (NREM) Rapid eye movement (REM) NREM sleep: Stage 1: relaxed, half-awake sleep Stage 2: brain activity slows and movement stops Stages 3 and 4: Blood pressure drops Heart rate slows Blood supply to brain minimized Stage 4 is referred to as deep sleep

The Structure of Sleep REM sleep: Brain activity becomes more like being awake Dreams are most likely to occur in this stage REM sleep paralysis: periods of no muscle tone and immobility Appears to give the brain the opportunity to “file” ideas and thoughts into memory Creative and novel ideas may be more likely to flourish

The Structure of Sleep Insufficient REM sleep may impair memory and the ability to learn new skills REM rebound effect: when long sleep is possible after inadequate sleep for several nights, you will have longer and more frequent REM sleep Demonstrates importance of REM sleep to the brain

Sleep Cycles After the first REM period, you cycle back and forth between REM and NREM stages Repeats about every 90 to 110 minutes until waking Children and adolescents experience large quantities of “deep sleep” As people get older, high-quality, deep sleep becomes more elusive Structure is essentially the same for men and women Women have more slow-wave sleep (NREM stages 3 and 4) and experience more insomnia

Sleep Cycles Figure 4.3 : One night’s sleep cycles. After your first REM period, you cycle back and forth between REM and NREM sleep stages. Typically, you experience four or five sleep cycles each night. After the second cycle, however, you spend little or no time in NREM stages 3 and 4 and most of your time in NREM stage 2 and REM sleep. After each successive cycle, the time spent in REM sleep doubles, lasting from 10 to 60 minutes at a time.

Sleep Disorders - Insomnia Insomnia: difficulty falling or staying asleep Can be caused by stress, anxiety, medical problems, poor sleep environment, noisy or restless partners, and schedule changes Distress over inability to fall asleep also contributes Improved sleep habits and exercise have been shown to improve sleep quality for chronic insomnia

Sleep Apnea Sleep apnea: periods of nonbreathing during sleep Almost 40% of U.S. population may have some form of sleep apnea Some 80–90% of cases are undiagnosed Central sleep apnea: brain fails to regulate the diaphragm and other breathing mechanisms correctly (rare) Obstructive sleep apnea: upper airway is obstructed during sleep Person is typically unaware of the typical pattern of snoring and gasping

Figure 4.4 Obstructive sleep apnea. (a) Normally, the airway is open during sleep. (b) When the muscles of the soft palate, tongue, and uvula relax, they narrow the airway and cause snoring. (c) If these structures collapse on the back wall of the airway, they close the airway, preventing breathing. The efforts of the diaphragm and chest cause the blocked airway to become even more tightly sealed. For breathing to resume, the sleeper must rouse enough to cause tension in the tongue, which opens the airway.

Sleep Apnea Obstructive sleep apnea is potentially dangerous, even fatal Associated with high blood pressure and increased risk of heart disease and stroke If not severe, sleep apnea can be addressed by behavioral strategies More severe cases are often treated with a continuous positive airway pressure (CPAP) machine Through a mask, pressurized air is gently blown into the patient’s nose

Sleepwalking Disorder Sleepwalking disorder: a person rises out of an apparently deep sleep and acts as if awake Episodes typically last less than 10 minutes Most sufferers have no family history of the disorder May be brought on by excessive sleep deprivation, fatigue, stress, illness, excessive alcohol, and use of sedatives

Sleep-Related Eating Disorder and Night Eating Syndrome Sleep-related eating disorder (SRED): a person rises from bed during the night and eats and drinks while asleep About three-quarters with this disorder are female The person has no memory of the episode (or multiple episodes), and does not experience indigestion or feelings of fullness Night eating syndrome: a person eats excessively during the night while awake Repeatedly awakens during the night to eat, then eats very little during the day

Evaluating Your Sleep Take the sleep latency test Sleep latency: amount of time it takes a person to fall asleep Check for symptoms of a sleep disorder Look at behavior change strategies If referred to a sleep clinic or lab, you may be asked to monitor your sleeping habits at home, or you may be evaluated in a lab Multiple Sleep Latency Test: administered as an index of daytime sleepiness, usually repeated five times during the day in a sleep clinic

Getting a Good Night’s Sleep Most people experience disordered sleep at some point, experiencing the symptoms of sleep disorders but less frequently and less severely Ways to ensure healthy sleep patterns include moderating technology use and adopting other sleep-friendly habits and behaviors

Taking a Break from Technology Artificial blue light from computers, televisions, and phones blocks the production of melatonin, the hormone that induces sleep If possible, turn off electronic devices at least 2 hours before going to sleep Alternately, dim brightness levels or adjust light sources from blues to reds Answering texts and calls interrupts sleep architecture and can also lead to awkward and embarrassing communications

Establishing Good Sleep Habits Maintain a regular sleep schedule Be smart about napping Create a sleep-friendly environment Avoid eating too close to bedtime Avoid caffeine, nicotine, and alcohol Get regular exercise but not close to bedtime Manage stress and establish relaxing bedtime rituals Consider your bed partner

Creating a Sleep-Friendly Environment Your bedroom should be comfortable, secure, quiet, cool, and dark, giving special consideration to the following: Choice of mattress and pillow Clean sheets Quiet Temperature Air quality Body position Chronic pain

Using Sleep Aids and Sleep Apps Frequently prescribed sleep medications induce sleep but suppress both deep sleep and REM sleep Daytime side effects include decreased memory and intellectual functioning Many OTC medicines contain antihistamines Can cause dehydration, agitation, constipation Rebound insomnia can occur, worse than before medication was taken A variety of smartphone apps can be calming and help induce sleep, or will track your sleep quality

Using Sleep Aids and Sleep Apps Many complementary and alternative products aim to address sleep problems Herbal products, most commonly valerian Can interact with other medication and drugs Dietary supplements, especially melatonin Aromatherapy, using certain scented oils Relaxation drinks, or anti-energy drinks Because of the potential for adverse affects, it is important to consult with your health provider

In Review How does sleep affect your health? What makes you sleep? What is the structure of sleep? What are common sleep disorders? How can you enhance the quality of your sleep?