Presented by: Mehrdad Ayati, MD
Clinical Instructor, Internal Medicine
Stanford University Medical Center
April 19, 2012
You go to bed, only to start tossing and turning, with no rest in sight. Or you fall asleep, only to wake up at 3 am. Having trouble falling asleep—or staying asleep—is a common problem, especially among older people.
But what is sleep exactly? And why does it become so elusive as we age? The reasons can range from physiological factors, such as chronic pain, hormones, or gastrointestinal problems, to environmental elements like light or noise, according to Mehrdad Ayati, MD, a clinical instructor of medicine, who spoke at a presentation sponsored by the Stanford Health Library.
We spend about eight hours a day, 56 hours a week, and 2,920 hours a year sleeping—almost a full third of our lives. But though sensory activity and voluntary muscles are on low, our brains are still quite active.
“Sleep is still a mystery,” said Dr. Ayati, “but we are understanding more about its function and what factors can affect our ability to sleep.”
Series of Cycles
Sleep involves a series of cycles triggered by a complex group of neurochemicals that respond to cues from the body and the environment. This sleep pattern follows an alternating cycle throughout the night. The first phase is called slow wave sleep, which is the deepest and most restorative stage. Slow brain waves occur at the beginning of the night, with a deep drop of consciousness. As we get older, however, there is a marked drop in these stages of our deepest sleep.
About 25 percent of sleep involves rapid eye movement (REM), the second cycle, which is associated with dreaming. REM sleep is sometimes called paradoxical sleep because the brain is still quite active. Blood pressure is low and muscles are inactive during REM sleep to prevent us from acting out our dreams. REM phases can last from five to 30 minutes, and most people can recall at least snatches of their dreams if they are wakened from this cycle. People with dementia tend to have more REM sleep and can develop REM sleep behavior disorders like sleepwalking.
Sleep is regulated by a complex network driven by several neurotransmitters, including acetylecholine, which appears to affect dreams; dopamine, which enhances wakefulness and alertness; and histamine, which can induce wakefulness (which is why many antihistamines cause drowsiness).
These neurotransmitters work in conjunction with our circadian clock, a biological time keeper that synchronizes our chemicals, hormones, body temperature, and sleep patterns. The circadian clock is also involved in the production of melatonin, a hormone produced by the pineal gland in the brain that is suppressed by light. Among other influences, melatonin regulates the core body temperature and circulation.
Together these processes control when we sleep and how deeply we sleep, said Dr. Ayati. For example, younger people spend more time sleeping and a greater percentage of sleep in a REM state compared with adults. He also described a typical wake-sleep cycle: Highest melatonin rates occur around 9 pm and production stops at 7:30 am; highest body temperature and blood pressure take place around 7 pm; deepest sleep takes place at 2 am, followed by lowest body temperature at 4:30 am.
Factors that can Affect Sleep
But as we get older, more internal and external factors can make sleep elusive or less satisfying. We spend more time in bed but more time awake, and the kind of sleep we get is the lighter stage. Dr. Ayati said close to 40 percent of older women develop sleep problems, usually related to hormone changes associated with menopause.
Sleep can also be affected by COPD and other respiratory problems; gastrointestinal ailments like irritable bowel syndrome; blood sugar fluctuations from diabetes; and chronic pain stemming from fibromyalgia and arthritis. There is a strong association between cardiovascular disease and sleep problems: people with sleep apnea, for example, are at a higher risk for heart attack.
But simply getting older may be the biggest cause of problematic sleep patterns. About 40 percent of older adults report having trouble falling asleep, and 30 percent report waking up in the middle of the night. About half use medication to help induce sleep, and more than half report experiencing daytime drowsiness. Almost two-thirds have some physical condition that can affect sleep.
Dr. Ayati said a key problem is that circadian rhythms change, causing sleep to become more fragmented, with disruptions from tossing and turning, and trips to the bathroom (a condition called nocturnia). For many people this change might be due to lifestyle changes, such as losing a loved one or limited social contact, which can cause anxiety. Because of physiological changes, medications, alcohol, and stimulants can also exert more influence over sleep patterns. Common prescriptions like antidepressants can actually make matters worse, he added.
“Older people are awake longer and more susceptible to changes in routine,” he said. “Over time the circadian cycle will change by itself.”
In hospitals and nursing homes, circadian cycles are affected by daytime napping, inactivity, noise, medication, and changes in routine.
Management and Treatment
A change in sleep hygiene is the best first step to managing and treating sleep problems.
“You can help yourself find your own circadian rhythm,” Dr. Ayati said. ”Go to bed the same time every day—even on weekends—and never go to bed unless you are sleepy. The bed is not the place to read, watch TV, or think.”
Though not a big proponent of naps, he did say that short naps of 15-20 minutes can be helpful for some people. He also suggested:
- Stay in bed only when asleep and get up as soon as you awaken
- Exercise daily but not just before bedtime
- Relax mentally before getting ready for bed
- A light snack is OK unless you have reflux
- Cut out caffeine, alcohol, and nicotine
- Control the noise, light, and temperature in your bedroom
- If you can’t sleep after 30 minutes, get up but keep lights low
He also recommends using cognitive behavioral therapy, a psychotherapeutic approach designed to influence behaviors and perceptions by modifying mental processes. Other approaches may include bright light therapy to enhance melatonin production and relaxation techniques. Prescription or over-the-counter medications can help but only as a short-term remedy since they can cause even more sleeping problems, he said.
About the Speaker
Mehrdad Ayati, MD, is a clinical instructor of internal medicine with a special focus in geriatric medicine. He received his medical degree from the Iran University of Medical Sciences. He completed his internship and residency at the University of California, Davis, and his fellowship at Stanford.
For More Information:
About Dr. Ayati
Stanford Sleep Center
Aging Adult Services