Wellness, Home & Lifestyle, Science & Tech

Sleep Across Our Life Span

Matthew Walker

Lesson time 12:23 min

Sleep evolves as we age. Explore how sleep is affected by the changes we experience and how better sleep can help prevent disease.

Students give MasterClass an average rating of 4.7 out of 5 stars

Topics include: Alzheimer’s Prevention


[MUSIC PLAYING] - You may have a sense that as you're getting older, perhaps the quantity and the quality of your sleep is a little bit harder to come by. And we know that aging will slowly deteriorate the quality and the quantity of your sleep. When we're very young in fact, even when we're in utero, we spend most of our time not in nonrapid eye movement sleep, not in deep non-REM sleep, but actually in REM sleep. And then in the first two years of life, we continue to feast on rapid eye movement sleep. And it's about a 50/50 distribution. So in our first two years of life, about 50% of our time is spent in non-REM sleep. And about 50% of that sleep time is spent in REM sleep. So as we shift from infancy through to childhood and then into our teenage years, we start to feast much more on nonrapid eye movement sleep and less on REM sleep. And once we get to adulthood, we seem to have this sort of 4 to 1 ratio. Almost like if you're thinking about mixing a sleep cocktail, it would be four parts non-REM and one part REM. As we get older, the continuity of our sleep decreases. In other words, we start to wake up more often. And we spend more time awake throughout the night. What we've also found is that the electrical quality of our sleep will begin to decline. And in fact, it starts to happen quite early. We can see the decline in your deep sleep electrical brain quality happening in your mid to late 30s, and then it declines significantly. In fact, the drop in deep sleep quality in particular is perhaps one of the most remarkable and robust physiological changes that we see across the entire lifespan. Doesn't that mean older adults simply just need less sleep? And the answer seems to be no. That's not true. It would be a little bit like saying, well, as we get older, our bones become weaker. So doesn't that just mean that older adults need weaker bones? Well, no. That increases their risk of fracture if they fall. And we actually will supplement the diet of older adults with things such as calcium to try and improve the strength of their bones. But we don't appreciate and think about sleep in that same way. And that's one of the myths. It's not as though we need less sleep as we get older. It's simply that our brains as they deteriorate, just like the rest of our bodies, our brains can't generate the sleep that they still necessarily need. One of the other features that we know happens as we get older is not just a change in the quantity and the quality of our sleep but also a change in our circadian rhythm. And more specifically, the strength of the signal of the circadian rhythm being drummed out by the brain actually starts to become a little bit more shallow, a little bit more muted. As we get older, we may find it more difficult to be active and alert during the day because we don't get the strong or as strong a signal from our circadian rhythm of the drive to be awake. And then similarly, we don't get the same...

About the Instructor

As a professor of neuroscience and psychology at UC Berkeley and the director of the Center for Human Sleep Science, Matthew Walker is an expert on sleep. In this class, he will illuminate the science behind sleep and teach you how to increase the quality and quantity of your sleep. Learn how to prevent sleep debt, navigate the effects of alcohol and caffeine, and improve your health. Your best sleep starts tonight.

Featured Masterclass Instructor

Matthew Walker

Neuroscience professor Matthew Walker teaches you the science of sleep and how to optimize it to better your overall health.

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