David PerlmutterPresident,, Perlmutter Health Center · Board-Certified Neurologist | Functional Medicine Pioneer | #1 New York Times Best-Selling Author | International Speaker | Host of The Empowering Neurologist Podcast

You May Be Measuring Sleep the Wrong Way

21 Aug 2026 · 1 min

Watch on YouTube

1:11

In this YouTube talk, Dr. David Perlmutter argues that the common focus on sleep duration overlooks the crucial importance of sleep quality, particularly time spent in deep sleep. He explains that deep sleep activates the brain's glymphatic system, which clears metabolic waste, misfolded proteins, and other debris, thereby supporting brain health. Perlmutter recommends using wearable devices such as the Apple Watch, Whoop, or Oura Ring to monitor not just total sleep time but also deep‑sleep metrics. He further suggests that lifestyle adjustments—like optimizing sleep environment, timing, and habits—can improve both the quantity and quality of sleep, ultimately enhancing the brain’s cleaning processes.

Chapters

How many times have you wondered if you're getting enough sleep? Well, I'm here to tell you that's one question, but another question that's equally important is how many times have you been asked about the quality of your sleep? The quality is something people don't really ask about, but these days we know that's really important. The reason we want to look at the quality and the quantity of our sleep is because quality has to do with how much time we're spending in, for example, deep sleep. Deep sleep is when we activate the glymphatic system. That is a system in our brain's physiology that allows the brain to really basically take out the garbage, if you will, to remove those products of brain activity, those misfolded proteins, those products of bacterial degradation, those products of even neuronal degradation, things that don't belong in the brain. So it means metricizing. It means gaining a sense of what's going on during our sleep period. By wearing an Apple Watch, a Whoop, or an Oura Ring to find out not just how long we are sleeping, but the quality of our sleep, and beyond that, then to see what our lifestyle changes can do to improve not only quantity, but quality as well.