Stay Sharp! Sleep, Aging, and Your Brain

It’s an unfortunate but nearly universal fact that as we age, we become a little less…um…what’s the word we’re looking for… quick. Or, as our slowed synapses might have it, the brain don’t work so good no more. This is nothing to get down on yourself for—deficits in cognitive performance are a universal consequence of the aging process. It can start from as early as 45 years old, and its myriad forms—cognitive decline, dementia, Alzheimer’s disease—stem from the same basic condition: age. Like your skin and your bones, your brain gradually becomes weaker over time, and things like learning new skills, retaining memories, and using language become more and more difficult. For most, it usually happens so slowly that it’s hard to notice that anything is happening at all.

So is there anything you can do to halt, or at least slow down, this process? For those of us already in the age group most likely to suffer from dementia and mental decline—65 years and older—a variety of methods may help slow the onset, including managing blood sugar levels, staying physically active, consuming a lot of antioxidants (berries are a brain favorite), and keeping the brain challenged with activities like crossword puzzles, ongoing study, and meditation.

But an ounce of prevention is worth a pound of cure. What can be done to reduce the risk of cognitive decline? How can we stop it before it’s begun? The tactics above are certainly useful, but there’s an undervalued factor that’s as simple and effortless as closing your eyes.

Oh yeah, we’re talking about sleep.

You probably already know that when you’re tired, your mind moves a little more slowly than usual, and science has proven this from every angle. Sleep deprivation severely diminishes your ability to learn and retain information, all while decimating your coordination and reaction time to boot.

What’s really troubling is that these problems compound over the long term. One day of low sleep will disrupt a litany of hormonal reactions that your body needs for optimal function. Fortunately, catching up on those lost Zs with some better sleep will more or less right the wrong—the body is nothing if not good at bouncing back.

But what happens if the body isn’t given the time it needs to recover? What if one day of bad sleep is followed by another, and another? A 2014 study in the American Academy of Sleep Medicine sought to answer that question by looking at 2,822 men with a mean age of 76 years. After using a wrist actigraph to study their sleeping habits over an average period of three and a half years, they found that fragmented sleep resulted in a 40 to 50 percent increase in the odds of clinically significant cognitive decline. This is such a severe increase that the study authors equated it with adding on five years of age. They also noted that cognitive impairment is actually increasing in the elderly, making it all the more important to nail down its causes.

Sleep (or lack thereof) is a pretty darn big one, and other studies have found plenty of reasons why. Sleep apnea, for instance, disturbs sleep quality and can result in less oxygen reaching the brain, and a 20-year study of Californian women found that women with problematic sleep were almost twice as likely to experience dementia or cognitive impairment. Other research has found that fragmented sleep, whatever its cause, results in an overall reduction in slow-wave sleep, which is crucial for normalizing cortisol and inflammation, which can both lead to mental decline.

In the end, sleep isn’t just important; it’s a pillar of a healthy lifestyle, equally as crucial as diet, exercise, and mental health. Indeed, it has a profound effect on all three. While six-pack abs may be impossible to maintain in a nursing home, cognitive function is—especially if you start sleeping better tonight.