Finding the Sweet Spot: How Much Sleep Is Just Right?
A recent study led by American researchers (and reported by CNN) took a close look at over 4,400 people averaging 71.3 years of age. Participants came mainly from the United States, Canada, Australia, and Japan—a real international slumber party. The scientists were careful to point out that their conclusions are based on self-reported data, which has its limitations. Still, after consulting other experts in the field, most of their observations held up.
One key takeaway: Both short and long nights of sleep can mess with the body’s ability to reap the full benefits of rest. Dr. Marc Rey, president of the French National Institute for Sleep and Alertness (INSV), sheds light on what’s happening in the brain:
“One of the roles of long, deep sleep is to vary the spaces between neurons. When we sleep, these spaces grow, making it easier for toxins to be flushed away from the body.”
One such toxin is beta-amyloid, which accumulates during daytime brain activity. This needs to be eliminated each day; sleep deprivation reduces the brain’s ability to do so. If left to build up, beta-amyloid is strongly suspected to contribute—at least in part—to neurodegenerative diseases such as Alzheimer’s.
The Dangers of Too Little—and Too Much—Sleep
A night that’s too short doesn’t just make you yawn at breakfast. According to the study, it can reduce your ability to learn, think, remember, and pay attention. Virginie Sterpenich, a neuroscientist from the University of Geneva in Switzerland and a specialist in sleep, confirms:
“Older adults’ brains are impacted by both a lack and an excess of sleep.”
Sleep itself changes with age—not only do we generally sleep lighter, but we also lose some deep restorative stages. As Sterpenich notes:
“When we’re young, sleep is deeper because much is new and needs to be processed. As we get older, we lose some of this deep sleep. The need for it seems to drop—but the need for good, restorative nights does not!”
If sleep is cut short, the brain simply doesn’t get enough time to recuperate. Daytime brain activity creates a kind of electrical buzz that leads to fatigue. At night, the brain needs a pause to sort out the events of the day and reorganize memories—a bit like running a nightly recap of your soap opera, just with more neurons involved.
How Aging Affects Our Relationship with Sleep
Technically speaking, the older brain needs more sleep to compensate for its declining capacity. Still, as Sterpenich assures us:
“There’s no need to worry about sleeping nine or ten hours a night if you feel well.”
Some people are simply ‘short sleepers’ and cope better with less rest. Yet, even they may find themselves indulging in longer nights when the chance arises. Sterpenich puts it simply:
“Like the recommendation to eat five servings of fruits and vegetables per day, you should make sure your sleep suits your needs and keep active during the day.”
- Watching screens late at night can make falling asleep harder, and leads to more sedentary evenings.
- Staying physically active, eating healthy, and not overdoing screen time applies to grownups as much as to kids—yes, really!
Our circadian rhythm—the internal clock guiding about 24 hours of wake and sleep—also changes as we age. According to Sterpenich:
“Its amplitude diminishes. The difference between being awake and resting becomes less pronounced.”
This means both lighter nights and sometimes feeling only half-awake after a long sleep, especially in older adults. Which might explain why the study found that seniors whose sleep periods are too long or too short experience more noticeable drops in cognitive abilities.
When More Isn’t Merrier: Sleep Excess and Its Pitfalls
Sterpenich cautions that sleeping an excessive 14 or 15 hours is cause for concern—it can even be a symptom of depression. Still, solid sleep is a known shield against brain degeneration. Dr. Rey agrees that while it’s harder to prove a direct link between too much sleep and cognitive decline, one thing’s clear:
“Sleeping more than nine hours leads to cognitive difficulties. But is it the excess rest leading to problems, or are early cognitive declines making people sleep more? It’s a bit of a chicken-and-egg question and still needs deeper study.”
So, whether you’re a night owl, an early bird, or more of a nap enthusiast, the simple message is this: When it comes to sleep in our senior years, balance is key. Listen to your body’s needs, keep moving during the day, and don’t be shy about hitting the hay—just not for half the day!
John is a curious mind who loves to write about diverse topics. Passionate about sharing his thoughts and perspectives, he enjoys sparking conversations and encouraging discovery. For him, every subject is an invitation to discuss and learn.
