“When we’re asleep, there’s an increased flow of fluid through the brain, and this is hypothesized to clear out waste products and lower their concentration,” he explained.
Among the waste products lowered by sleep are the proteins beta amyloid and tau. At night, both of these proteins are released less and cleared more. In people who develop Alzheimer’s, both proteins build up to dangerous levels. Beta amyloid forms sticky clumps that interfere with signaling between neurons, and tau forms tangled knots that kill the neuron itself. When these proteins can’t be normally removed, they may be more likely to eventually begin sticking together into pathological forms, Lucey said.
Other proteins implicated in different kinds of dementia also follow this circadian waste removal rhythm, he added. “We’ve also looked at alpha synuclein, a protein that is important in both Parkinson’s disease and Lewy body dementia, and whose concentration increases with sleep deprivation.”
Sleep’s effects on cognitive health may range far beyond protein clearance. Inadequate sleep is also associated with atherosclerosis, hypertension, obesity, diabetes and depression — all of which are important risk factors for Alzheimer’s disease and other dementias.
“An important question for the field to study is how sleep disturbance in people with diabetes or obesity changes their risk of developing Alzheimer’s disease,” Lucey said. “Treating sleep disorders may be even more important in these individuals.”
Sleep: Just one healthy habit that benefits the brain
“Sleep is one potential risk factor associated with dementia, but it’s not the only one,” said Claire Sexton, director of scientific programs and outreach at the Alzheimer’s Association. Her suggestion: Don’t focus on just one factor. Instead, “try to create a healthy lifestyle that might actually, truly help prevent dementia.” A nutritious diet, physical activity and social engagement have also been linked to better brain health.
The Alzheimer’s Association is putting sleep front and center in its own research right now. The group has just launched U.S. POINTER-zzz, a $5.3 million study to examine whether lifestyle changes that might reduce Alzheimer’s risk also improve sleep. U.S. POINTER-zzz is a substudy of U.S. POINTER, a two-year clinical trial testing whether a combination of exercise, diet, mental stimulation and social support can reduce the risk of dementia in people who may be at increased risk for cognitive decline.
U.S. Pointer-zzz is recruiting subjects for the study. You may qualify if you are 60 to 79 years old, not a regular exerciser and have a risk factor for memory loss (family history of memory problems or slightly high blood pressure, cholesterol or blood sugar). You can learn more about U.S. Pointer here.
Sleep-starved? Tips for dealing with insomnia
The bad news: Sleep problems might increase your risk of dementia. The good news? You can do something about it.
“People often think that poor sleep is something that just happens naturally as we get older, that it’s something we have to live with and can’t do anything about,” said Ronald Chervin, M.D., a neurologist and director of the Sleep Disorders Centers at the University of Michigan. “That’s simply not true. Poor sleep is not a feature of getting older. And if you’re not sleeping well, instead of suffering and just accepting it, talk to your primary care doctor or a sleep medicine physician. Usually there is a diagnosis and a treatment available.”
In the meantime, here are some of Chervin’s top tips for improving your sleep.
- Control your environment. A comfortable bed in a cool, dark, quiet room is the most conducive setup for high-quality sleep.
- Limit screen time for an hour or two before bed. “TV is full-spectrum light, and phones and tablets emit a lot of blue light, which can reset our circadian rhythm and delay sleep onset,” he said.
- Avoid stressful mental pastimes before bed. This might mean switching off the TV or closing your book, depending on the content.
- Avoid alcohol for a few hours before bedtime. It’s a sedative, true, but a short-acting one that leaves you vulnerable to abrupt waking once the effect of the alcohol wears off.
- Exercise regularly, but earlier in the day rather than close to bedtime.
- Establish a routine that lets your brain know sleep is coming soon. Set a regular bedtime, and if you are vulnerable to insomnia, set a regular wake-up time.
- Talk to your doctor about cognitive behavioral therapy for insomnia (CBTI). This psychological intervention is part education and part behavior modification. Usually delivered by a trained professional, it can encompass sleep restriction initially while you learn to sleep efficiently again, as well as other techniques that have been demonstrated by years of research to help restore — and then maintain — healthy sleep.