We’re often told sleep is good for our brains, but too many daytime Zs may be a red flag.
As with practically everything associated with the Mediterranean lifestyle, we’re used to hearing that an afternoon nap — or siesta, if you’re feeling continental — is good for our brain health. A recent study however has highlighted a worrying association between taking longer daytime naps and developing Alzheimer’s disease.
According to The Guardian, the study, which followed over 1,400 participants around 81 years old for several years, discovered that those who napped for longer than an hour each day were 40% more likely to develop Alzheimer’s than participants who napped for less than an hour. The same association was noted in people who napped more frequently — with participants who napped at least once daily exhibiting a 40% higher risk of Alzheimer’s than those who didn’t nap every day.
Crucially, excessive napping was found to be a symptom, rather than a cause of dementia. So while sleeping in the afternoon won’t necessarily cause cognitive decline, it may be a sign that some impairment is already underway.
We spoke to Elias Zerhouni, M.D., a founding board member of Davos Alzheimer’s Collaborative and former director at the National Institutes of Health, and Dr. Dalia Lorenzo, a neurologist at Baptist Health’s Miami Neuroscience Institute, to unpack these findings — and get a little more background on how to spot the signs and symptoms of Alzheimer’s, and how to spot them.
How much napping is too much napping?
As Dr. Lorenzo explains, excessive napping can occur as a result of many different conditions — including medication side effects, untreated sleep apnea, and depression — so it’s not a specific marker for any one condition.
“That being said, the degeneration of areas of the brain that occurs in dementia, such as Alzheimer’s dementia, can involve centers of alertness,” she notes. This degeneration in the brain can lead to long periods of impaired alertness, or lethargy and excessive napping.
The neurodegeneration found in conditions like Alzheimer’s dementia and frontal temporal dementia also occurs in a particular order. This means that one part of the brain is affected first, before the disease moves on to the next.
“Because of this progression, the symptoms that crop up for patients also change over time,” Dr. Lorenzo explains. “For example, in Alzheimer’s dementia, the temporal lobes, which subserve short-term memory, are usually affected first. That is why the initial symptom commonly reported is short-term memory loss. As the neurodegeneration spreads to other areas of the brain, other symptoms can start to show up, such as difficulty with spatial functioning like getting dressed.”
Other neurodegenerative disorders can cause patients to experience an irresistible urge to sleep during the day, and conditions like narcolepsy and Parkinson’s disease also have significant sleep-related symptoms, so it’s important to seek medical advice before jumping to any conclusions over what’s prompting daytime sleep.
We’re often told sleep is good for our brains. But what’s the ideal amount of sleep for neurological health?
This can vary according to age, but Dr. Zerhouni notes that recent studies point to between 5.5 and 7.5 hours per night for maintaining brain health. Quality sleep is critical too. “Being asleep for a long time, but having that sleep be interrupted frequently, is not likely to yield the benefits of deeper sleep for fewer hours,” he says. So being in bed for nine hours but waking up for half an hour every 90 minutes won’t necessarily provide the benefits that shorter, uninterrupted sleep might.
The amount of uninterrupted sleep you need to remain healthy is individual — you may need more (or, if you’re very lucky, less!) sleep than the “optimal” average number to stay well.
“Most people require about 7-8 hours of sleep to feel fully rested and to gain maximal benefits of recharging the brain and body for the following day,” says Dr. Lorenzo. “But there are people, and it should be emphasized that this is a minority of people, who require only 4-6 hours to feel fully rested.” Others, she adds, may need 9-10 hours of sleep to feel their best.
How can we find out how much sleep is best for us?
“Usually, the best way to determine your individual sleep needs is during periods where you can sleep at liberty,” says Dr. Lorenzo. A two-week vacation during which there’s no need for an alarm clock or any early rising would be ideal.
“Usually it’ll take a few days, or up to a week, to catch up on sleep after the chronic sleep deprivation that many people live with routinely,” explains Dr. Lorenzo. “After that initial payback, however, we usually settle into a sleep pattern that’s more natural to our physiology.” So whether you’re an early bird or a night owl, your sleep cycles will be most efficient when they’re aligned with your natural tendency.
What are some key warning signs of dementia?
When a person finds themself struggling with problem solving, memory, or interpreting the world around them in a way that feels out of step with their “usual” abilities, that can be a subtle sign of dementia.
“Patients may report having difficulty cooking a meal they have made for many years,” explains Dr. Lorenzo, “Or they may say that they’re not able to wrap their mind around how to solve a problem they could previously have managed.” Learning new things and recalling information can be particularly difficult, as can anything that requires concentration. Patients often begin to struggle with language: mispronouncing words, not being able to think of the right words, or saying the wrong words.
These difficulties can also extend to spatial skills, like those required to use cell phones, remote controls, or tools. “Familiar tasks that require multistep processes, such as getting dressed or getting ready for bed, may take longer,” explains Dr. Zerhouni.
In some patients, these changes can extend to a patient’s mood, personality, and judgment. “Patients can develop apathy, and appear withdrawn from their usual activities,” says Dr, Lorenzo. “They can have impaired judgment and be taken advantage of — or conversely, develop delusions and become very suspicious.”
What should you do if you notice dementia warning signs in yourself or someone else?
“Consult with a doctor immediately,” says Dr. Zerhouni. “A number of conditions can result in memory loss or other dementia symptoms, but Alzheimer’s treatment begins with identifying the issues and obtaining a diagnosis as early as possible — through psychiatric evaluation, cognition screening, and standard medical tests and brain scans.”
It’s also important to remember that all those healthy lifestyle choices that benefit your body will also benefit your brain. Eating nutritious foods, exercising both your body and mind with activities as simple as walks and crosswords, and receiving psychiatric treatment if needed, can all help you stay sharp for long into your golden years.
