Presented by: Rachel Manber, PhD
Professor, Psychiatry and Behavioral Sciences
Director, Insomnia and Behavioral Sleep Medicine Program
Stanford University Medical Center
May 5, 2011
Some changes in sleep are a natural part of getting older. Many older adults tend to wake up more often during the night, with more fragmented sleep, and experience a decrease in the deepest sleep stage, known as slow wave sleep. Changes in circadian rhythm (the internal clock that tells you when to sleep and when to wake up) may be part of the reason why older people go to sleep earlier in the evening and wake up earlier in the morning.
However, ongoing sleep difficulties and waking up tired every day are not a normal part of aging, said Rachel Manber, PhD, a professor of psychiatry and director of Stanford’s Insomnia and Behavioral Sleep Medicine Program, at a presentation sponsored by the Stanford Health Library. Dr. Manber is the author of a book on the subject called “Quiet Your Mind and Get to Sleep.”
Sleep is not a unified state. It involves a series of cycles between rapid eye movement (REM) sleep and non-REM sleep, which is made up of stages—Stage 1 is light, Stage 2 is deep enough that you are aware that you have been asleep, and Stage 3 is the deepest and most restorative stage. This sleep cycle tends to follow a 90-minute pattern throughout the night.
For most young people, the slow brain waves of Stage 3 take place during the first two or three hours of sleep, so even when they do not sleep enough they are not sleep-deprived. As we age, however, there is a drop in deep sleep and sleep patterns become more fragmented, with disruptions from tossing and turning, stress, and trips to the bathroom.
“As we get older we tend to get more lighter-stage sleep and experience more wakefulness,” said Dr. Manber. “Generally we don’t lose the ability to fall asleep but rather the ability to sleep for long periods of time. We’re less able to experience the consolidated sleep we had when we were younger.”
Older people tend to be less affected by sleep deprivation, she added, and appear to be able to function better with less sleep than younger people.
Although older women tend to report poor sleep more often than men, Dr. Manber said that laboratory tests show that women may actually be sleeping as well or better than men. It’s also unclear whether older people may actually need less sleep or are responding to age-related changes in the ability to fall asleep and remain asleep, she added.
A recent study by the National Institutes of Health suggests that healthy older people may require about 1.5 hours less sleep than younger adults, an average of 7.5 hours per night. The study also indicates that seniors sleep less even when given the opportunity for more sleep.
Sleep is regulated by two interconnected processes—the sleep drive and the circadian clock—that create our sleep patterns, the balance between the drive to sleep and the factors that prevent it. Sleep drive is the force toward sleep that accumulates until the body can be replenished with slumber. Its counterpoint is the circadian clock, a biological time keeper that synchronizes our sleep patterns with daylight and signals us when to wake.
“Both aspects need to be aligned so that the sleep drive is high and the sleep opportunity is congruent with the circadian clock,” Dr. Manber said. “
Some people have a biological clock that is naturally advanced. These “larks” go to bed earlier than most people their age and cannot sleep after a certain point in the morning. For others, the alert signals from their natural biological clocks stay on longer, causing a delayed sleep phase. These “night owls” are still wide awake in the evening, have trouble falling asleep, and have great difficulty waking up.
While most people do follow a normal circadian rhythm, larks and owls maintain a variance that they should learn to accommodate. Bright light can help reset the body clock, but needs to be applied regularly to realign the circadian system and strengthen the sleep drive signal.
When Sleep is an Issue
Normal sleep is determined by three factors: a strong sleep drive, a correctly timed opportunity for sleep, and a low arousal threshold.
In primitive times outside threats lowered the arousal threshold, but today’s manmade problems can increase arousal and override the need for sleep.. Hyperarousal can lead to insomnia, a condition defined by difficulty falling asleep or staying asleep, waking up too early, or experiencing poor quality sleep.
“Insomnia is a 24-hour disorder,” said Dr. Manber. “It involves poor sleep at night and impaired function during the day. It impacts your life, not just your sleep.”
Acute insomnia is usually a response to a situation: worries about work, family, or health. However the condition may become chronic if sleep remains elusive after the stress subsides or the person adjusts to the situation. Dr. Manber compared insomnia to a Pavlovian response: the insomniac becomes conditioned to associating the bed with sleep problems, which perpetuates the sleeplessness.
“People with insomnia tend to try harder to fall asleep,” she said. “A combination of external factors and a genetic predisposition toward internalizing stress can create a cycle of non-sleep. The more you try to control your sleep, the worse it gets.”
When insomnia patients try to suppress their thoughts when trying to try to sleep, it takes them longer to drop off and the quality of their sleep is worse. They demonstrate cognitive arousal—their mind literally cannot shut down. They suffer from pre-sleep anxiety, anticipating problems with sleep and following rigid rules to protect their time.
Dr. Manber described a study that compared sleepiness levels during the day for insomniacs and people who had been deprived of sleep to the same degree. Given opportunities to take naps during the day, the insomniacs took longer to fall asleep and remained more tired than the sleep deprived. “The study showed that people with insomnia may be tired, but they are not sleepy,” she said. “Insomnia results in sleep deprivation because of internal reasons. Sleep deprivation of good sleepers by external reasons leads to sleepiness.”
Dr. Manber teaches skills to help people stop thinking about their problems falling asleep. She uses cognitive behavioral therapy, a psychotherapeutic approach designed to influence behavior by modifying mental processes. Studies have shown that this approach is as effective as medication with the added benefit of lasting longer, being more cost effective, and inducing no unwanted side effects that are often associated with drugs.
She also had some specific suggestions for those who find sleep elusive:
- Do not spend much time awake in bed
- Establish a regular wake-up time that fits your circadian clock
- Go to bed only when sleepy
- Do not try to force yourself to sleep
About the Speaker
Rachel Manber, PhD, is a professor in the Department of Psychiatry and Behavioral Sciences and director of the Insomnia and Behavioral Sleep Medicine Program, part of the Stanford Sleep Disorders Clinic. Her work focuses on behavior modification interventions to treat insomnia and other sleep disorders. Dr. Manber received a PhD in mathematics from the University of Washington and a PhD in clinical psychology from the University of Arizona. After teaching in universities in Wisconsin and Arizona, she joined Stanford in 2000.
For More Information:
About Dr. Manber
Insomnia and Behavioral Sleep Medicine Program
Google knol article
“Quiet Your Mind and Get to Sleep”