How Sleep Changes as We AgeChanges in your sleep patterns are a normal part of aging. In general, people tend to have a less satisfaction and more trouble with sleep than when they were younger - this includes both falling asleep and staying asleep [National Sleep Foundation]. As a result, an extremely common misconception about sleep is that we need less sleep as we get older. You may have heard such from your grandparents or even wondered about it yourself.
In actuality, our need for sleep remains constant throughout life. It's also no coincidence that many (though not all) older Americans report being less satisfied with and restored by sleep. For these reasons, it's not uncommon for our sleep habits to change as we age. Have you been craving a nap in the afternoon more and more as you get older? Has your "getting up" time been moved back earlier and earlier over the years? If you are answering yes to these questions, it's likely age related sleeping changes.
What are the Five Stages of Sleep?Sleep occurs in five stages and two different types of sleep: (1) Non-Rapid Eye Movement (NREM) and Rapid Eye Movement (REM) sleep. These periods include dreamless periods of light and deep sleep, and periods of active dreaming sleep. While we sleep, we cycle through these stages multiple times throughout the night. These stages are [Sleep Association]:
- Stage 1 (NREM): lightest stage of sleep which includes Alpha phase (daydreaming, meditation) and Theta phase (twitching, in between awake and sleep), and is characterized by normal breathing, muscle tone present, slower EEG brain frequency
- Stage 2 (NREM): light stage of sleep that lasts about 20 minutes, breathing slows, body temperature drops, heartbeat slows and brain begins to disengage from surroundings
- Stage 3 (NREM): transition between light and seep stages of sleep where brain begins to send Delta waves throughout body
- Stage 4 (NREM): very deep sleep with slow brain waves (Delta) that lasts about 30 minutes, muscles fully relaxed, energy is restored in body (gives you the sense of restoration), and anti-stress hormones released
- Stage 5 (REM): deepest stage of sleep (and where dreams occur) but with most brain activity, body is immobilized
Simplified graph showing 5 stages of sleepWhen you go to sleep, your body may go through this sequence in order, but once achieved it may skip around between the stages - people tend to experience REM sleep 4-5 times per night.
Aging and the Stages of SleepIn addition to having more trouble falling and staying asleep, older people tend to [National Sleep Foundation]:
- Spend more time in the "lighter" stages (stages 1 and 2) of sleep
- Spend less time in the more restorative, deeper stages (stages 4 and 5)
- Experience less REM sleep
- More awakenings during sleep cycle during the night
- Increase in medications
- Going to sleep earlier
- Physical conditions/illnesses
- Natural changes to circadian rhythm
Potential Sleep Problems Not Related to Age
Older people tend to exhibit more sleep disorders [NSF's 2003 Sleep in America], and may be more prone to sleep disorders. This is an important fact to recognize. It's also important to recognize what may be normal (albeit confounding or confusing changes) and what are abnormal sleep changes.
While a shift in circadian rhythm (earlier to bed, earlier to rise) may be normal, early to bed and late to rise is not considered a normal circadian rhythm shift. While it may be normal to feel less satisfied in the morning and want a nap in the afternoon, chronic sleepiness all day long is generally not a normal part of aging. Having trouble falling asleep may be normal, but lying in bed for hours every night is likely abnormal and not related to aging.
The main point is this: sleep changes as you age are normal, as discussed, but extreme changes or changes that interfere with your ability to be healthy and functional are likely not related to aging. Pay attention to the factors that may be causing a sleep disorder:
- Large hormonal changes later in life
- New medications
- Not getting enough physical activity
Keeping a sleep journal over the course of several weeks and noting down your struggles is an extremely valuable tool to bring to a doctor or sleep specialist to address any concerns you might have.