Older Adults And Diminishing Rem Sleep: Why And How?

Sleep patterns change as we age. Older people tend to have a harder time falling asleep and wake up more often during the night and earlier in the morning. They spend less time in deep, dreamless sleep and have more fragmented sleep. This is due to a combination of physiological changes in sleep, changes in sleep-related habits, and increased rates of sleep disorders.

Older adults experience shorter total sleep time (TST) than younger adults, with total sleep time decreasing until about age 60, then stabilizing through the later decades of life. This may be due to a combination of physiological changes in sleep, changes in sleep-related habits, and increased rates of sleep disorders.

Older adults spend a lower percentage of their sleep time in both slow-wave (a.k.a. deep sleep) and REM sleep compared to younger adults, and the time it takes to fall asleep increases slightly as well. The number of arousals and total time awake after falling asleep also increases with age.

Circadian rhythms become weaker and are less responsive to external stimuli and tend to shift earlier with advancing age.

The production of melatonin, which is normally produced in response to darkness and helps promote sleep by coordinating circadian rhythms, decreases as people age.

Older adults experience a shift in sleep timing, with a tendency to go to bed and wake up earlier

Older adults tend to experience shorter total sleep time (TST) than younger adults, with TST decreasing until about age 60, then stabilising through the later decades of life. This may be due to a combination of physiological changes in sleep, changes in sleep-related habits, and increased rates of sleep disorders.

The circadian rhythm in older adults becomes weaker and tends to shift earlier with advancing age. This is caused by age-related neuronal loss in the suprachiasmatic nucleus, reduced production of melatonin, and eye changes that reduce the ability of light to reach the retinal ganglion cells responsible for circadian entrainment. As a result, older adults become sleepy earlier in the evening and wake up earlier in the morning.

Older adults also experience a decrease in melatonin secretion, which is normally produced in response to darkness and helps promote sleep by coordinating circadian rhythms. This can further contribute to the shift in sleep timing.

In addition to these changes in sleep timing, older adults may also experience an increase in daytime napping. This can be attributed to biological changes, as well as lifestyle changes that accompany ageing. For example, older adults may have more time for napping during the day due to reduced work, physical, and social activity.

Older adults experience reduced slow-wave sleep, which is the deepest sleep stage

The amount of slow-wave sleep begins to decline in early adulthood. Elderly adults typically experience shorter periods of slow-wave sleep, and fewer of them. This is a consistent and most prominent finding across studies.

Older adults tend to wake up more often during the night, and their sleep is more fragmented and lighter, with brief arousals or longer awakenings throughout the night.

The reduction in slow-wave sleep may be related to a decrease in the production of melatonin, which is normally produced in response to darkness and helps promote sleep by coordinating circadian rhythms.

Older adults experience impaired sleep maintenance, with more frequent awakenings during the night

The body's internal clock, known as the suprachiasmatic nucleus (SCN), is responsible for regulating 24-hour daily cycles, including sleep patterns. As people age, the function of the SCN deteriorates, disrupting circadian rhythms and causing older adults to feel tired earlier in the evening and wake up earlier in the morning. This shift in sleep timing is known as a phase advance.

In addition, older adults experience a decrease in the production of melatonin, a hormone that is normally released in response to darkness and helps promote sleep. This reduction in melatonin secretion can further disrupt sleep patterns.

Other factors that can contribute to impaired sleep maintenance in older adults include the presence of medical and psychiatric conditions, such as arthritis, congestive heart failure, depression, and gastroesophageal reflux disorder. Respiratory disorders, such as sleep apnea, also become more common with age and can lead to multiple arousals during the night.

Furthermore, lifestyle changes that often accompany aging, such as retirement and social isolation, can increase stress and anxiety, which can also contribute to sleep disturbances.

To improve sleep maintenance, older adults can implement strategies such as exercising regularly, reducing exposure to stimulants like caffeine, avoiding naps during the day, and establishing a consistent sleep schedule.

Older adults experience a decrease in the amount of time spent in REM sleep

Sleep patterns change as we age, and older adults experience a decrease in the amount of time spent in REM sleep.

REM sleep is one of the two main types of sleep, the other being non-rapid-eye-movement (NREM) sleep. NREM sleep is further broken down into three distinct stages: N1, N2, and N3. N1 sleep is very light sleep; N2 is slightly deeper sleep; and N3, also called slow-wave sleep, is the deepest NREM sleep stage. REM sleep, on the other hand, is characterised by rapid eye movements and a "desynchronized" EEG pattern consisting of low-voltage, high-frequency waves. Most vivid dreams occur during this stage.

As people age, they tend to spend less time in REM sleep. This is due to a variety of factors, including changes in the body's internal clock, reduced melatonin secretion, and an increase in medical and psychiatric conditions that can disrupt sleep. Additionally, older adults may nap more frequently during the day, which can further disrupt their sleep patterns.

The decrease in REM sleep can have significant health effects, including increased daytime sleepiness, cognitive impairment, and cardiovascular issues. However, it's important to note that the relationship between REM sleep and memory consolidation is still not fully understood, with some researchers arguing that REM sleep may not have any function in memory consolidation at all.

To improve sleep quality, older adults can take steps such as exercising regularly, reducing exposure to stimulants like caffeine, avoiding substances that interfere with sleep, and maintaining a regular sleep schedule.

Older adults experience a reduction in sleep efficiency, with a greater proportion of time spent awake during the night

The body's internal clock, or the suprachiasmatic nucleus (SCN), is responsible for regulating 24-hour daily cycles, known as circadian rhythms. As people age, the function of the SCN deteriorates, disrupting circadian rhythms and causing people to feel tired earlier in the evening and wake up earlier in the morning. This is known as a phase advance. Older adults may also experience a reduced ability to adjust to changes in their sleep schedules, such as during daylight savings time or jet lag.

In addition to changes in the SCN, decreased production of the hormone melatonin may also play a role in disrupted sleep in older adults. Melatonin is typically produced in response to darkness and helps promote sleep by coordinating circadian rhythms. However, as people age, the body secretes less melatonin, which can contribute to sleep disruption.

Mental and physical health conditions, such as depression, anxiety, heart disease, diabetes, and arthritis, may also interfere with sleep in older adults. The use of multiple medications to manage these conditions can further contribute to sleep issues. Lifestyle changes that often come with aging, such as retirement and social isolation, can also increase stress and anxiety, impacting sleep quality.

The combination of these factors can lead to older adults waking up more frequently during the night and experiencing more fragmented and less restful sleep. This reduction in sleep efficiency can have negative consequences on overall health and quality of life.

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