Why Do We Sleep Less As We Age?

As a teenager, could you easily sleep until noon, if uninterrupted? Many teenagers get a whopping 12 hours of sleep per night, but unfortunately, to many of us, this number is simply a dream. But why does it get harder to sleep as we age? And what are the consequences?

Latest Evidence on Sleep and Aging
A recent scientific review published in Neuron explains that as we age, we lose the ability to get restorative sleep. Starting in your mid-30s, it takes longer to fall asleep, you spend fewer total hours asleep, have a reduced amount of non-REM sleep (a.k.a. deep sleep), and are more restless throughout the night. One possible explanation for these changes comes from studies in rats, in which researchers found that the number of brain cells responsible for sleep and wake stability decrease by 40% over their lifespan. This lack of restorative sleep has major effects on the brain, in terms of memory and learning ability. In fact, evidence shows that lack of sleep is linked with reduced working memory and reasoning. Other rat studies have even shown that a chronic lack of sleep is connected with many diseases, including Alzheimer’s and cancer.

Why Does This Happen, and What Can You Do?
Scientists hypothesize that either our sleep needs decrease as we age OR that we need the same amount of sleep as we age, but our ability to get that sleep decreases. Although there is support for both ideas, the best current evidence points to the idea that our sleep needs remain the same, but our biological ability to meet those needs is impaired as we age.

But don’t lose more sleep over it: If you want to work on meeting your sleep needs, the Sleep Foundation has several tips on how to maximize sleep, including a regular sleep schedule and daily exercise.

(Feature photo courtesy of pixabay.com)

Tara Grieshaber

Tara Grieshaber is an intern with the Healthy Aging Project, and a student in the Integrative Physiology Department at the University of Colorado Boulder.