As we age, the way we go through the different stages of sleep throughout the night changes. A good night’s sleep is typically made up of 4 to 6 sleep cycles, each lasting 90 to 110 minutes. Each cycle contains four phases. The first three phases are known as non-REM, so they are labeled NREM1, NREM2 and NREM3. Then, we finally slip into REM, aka dream sleep.
“With typical aging, there’s a pretty consistent pattern, so generally, with aging, individuals get less slow-wave, or we also call that deep sleep or non-REM stage 3 sleep; they get more light sleep or non-REM stage 1, stage 2 sleep,” Drerup says. Some of the factors that contribute to older adults getting less restorative sleep include pain, arthritis, needing the bathroom more frequently during the night or disruptions from sleep partners, like snoring. Getting less restorative sleep also increases the risk for sleep disorders like sleep apnea or periodic limb movements, both of which can further disrupt sleep.
Another common issue with aging is how circadian rhythms are influenced by the timing of our sleep. “Older adults commonly will develop an earlier circadian timing, so they get sleepy earlier and have an earlier wake time. So, they have a weaker circadian signal—oftentimes that will contribute to the earlier bedtimes and wake times.” In addition, Drerup says that melatonin rhythms are less robust with aging and that older adults have weaker responses to light, both of which help regulate sleep.
Sleep Apnea and Insomnia in Older Adults
With aging, insomnia rates also increase. Drerup explains that a common situation she sees with older adult patients is that when they retire, they can actually have more problems sleeping because they lack a consistent routine and their activity levels decrease. Other external daytime cues or zeitgebers like light exposure, social interaction and exercise can also impact sleep/wake rhythms. “Sun is the cue to readjust your internal clock, your circadian rhythm and your hypothalamus,” says Dr. Sameh Aziz, a pulmonary and critical care medicine physician for Carilion Clinic. And while there isn’t a standardized range for hours of sunlight per day, Aziz shares that he believes older adults “need 4 to 5 hours of sun exposure during the day; it definitely would vary based on their living situation and is going to vary by season as well. With daylight saving time, you have very limited exposure to light.”
To help get to the root cause of insomnia in older adult populations, Aziz recommends starting by evaluating sleep hygiene. He recommends having a fixed time to go to sleep and to wake up, staying active with social interaction and exercise and optimizing one’s sleep environment. That means ensuring an optimal temperature, a comfortable and supportive mattress and comfortable pillows. He also recommends minimizing exposure to screens, caffeine, alcohol and tobacco before bed. If you’re taking medication, check with your doctor to ensure that you’re taking the proper dose and discuss any side effects that may negatively affect sleep.
Napping in Older Adults
Napping during the day can be beneficial, as long as naps don’t take away from nighttime sleep, Drerup says. “Sometimes people get days and nights switched because they’re sleeping a lot during the daytime because of a lack of social engagement or schedule, and then they won’t need sleep at night,” she says. Drerup recommends taking a 20-minute power nap, or if a longer nap is warranted, aiming for at least 60 to 90 minutes so that you get a full sleep cycle. Anything within that range can make you feel sleepy or groggy because you’re waking from stage 3 sleep. If napping does start to impact sleep duration and sleep quality during the night, it might be time to reset by either decreasing the length of naps or cutting one out and increasing activity to help drive sleep pressure for nighttime sleep.
Cognitive Decline in Older Adults
The biggest concern for older adults is that poor sleep is associated with impaired cognition, including difficulty focusing, concentrating or accessing short-term memory. “There are some studies suggesting higher risks of dementia and higher mortality risks,” Drerup says. “It’s very complex because it’s not necessarily causality, and it’s often bi-directional. Poor sleep can potentially contribute to cognitive issues. But also, poor sleep can be an early marker of disease.” One study published by the National Institutes of Health found that lack of sleep in middle age may increase dementia risk. The study’s findings suggest that “people who slept 6 hours or less per night in their 50s and 60s were more likely to develop dementia later in life” and that “inadequate sleep duration could increase dementia risk and emphasize the importance of good sleep habits.”
Seniors’ Sleep and Mental Health
Poor sleep can also negatively affect mental health and emotional regulation in older populations. “Because they’re having poor sleep, they’re always depressed, and they also have underlying irritability and anxiety,” Aziz says. In addition, if older adults feel fatigued, they may be more likely to socially isolate—either because they feel unsafe leaving the house or because they need to catch up on sleep—which can contribute to depression.