Wellness, Home & Lifestyle, Science & Tech

Sleep and the Human Body

Matthew Walker

Lesson time 17:05 min

Matthew explains how we can learn to boost our immunity and reduce health risks by sleeping better.

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

Topics include: Improve Your Immunity • Your Hormonal Health • The Cancer Connection • Preserve Your DNA


[MUSIC PLAYING] - So when it comes to your physical health, sleep may be as, if not more important than, diet or exercise. We often think of sleep perhaps as the third pillar of good health alongside diet and exercise. But in truth, that's not really the case. Sleep is actually the foundation on which those two other pillars will sit. So many of us when we get sick, what we typically want to do is just sort of curl up in bed and go to sleep. And the reason in part is because we're actually trying to sleep ourselves well. There is a very intimate association between your sleep health and your immune health. And so that mentality, that idea you can sleep when you're dead, well, firstly, we know from the evidence that that is mortally unwise advice. If you adopt that mindset, your quality of life will be worse. And your lifespan will be significantly reduced. That's what epidemiological studies teach us across millions of individuals. There's a very simple truth. The shorter your sleep, the shorter your life. But let's come back to the story of sleep and the immune system. Firstly what we know is that individuals who report sleeping less than seven hours of sleep a night are almost three times more likely to become infected by the rhinovirus, which is the common cold. We also know that individuals who sleep five hours or less a night are almost 70% more likely to become infected by pneumonia, a respiratory infection that we know is associated with conditions such as COVID infection. In one study, they took a group of healthy individuals. And rather than deprive them of sleep for an entire night, they actually just limited them to four hours of sleep for one night. And they focused on a critical immune factor. In fact, these are called natural killer cells. And you can think of natural killer cells almost like the Secret Service agents of your immune system a little bit like James Bond. And they are very good at identifying dangerous unwanted elements and eliminating them. And when they looked at these individuals who'd been limited to four hours of sleep for just one night, what they found was a 70% drop in natural killer cell activity. That is an alarming state of immune deficiency. And it happens quickly after just one short night of sleep. And I should note by the way that those natural killer cells, one of the things that they will be preventative of and are wonderful assassins against are cancerous cells. Now, it's not to suggest that short sleep is associated with every single form of cancer. That's not true. But what we do know is that short sleep duration has been associated with a doubling of your risk for the development of things such as lung cancer, ovarian cancer, as well as thyroid cancer, even myeloma, which is a form of blood cancer linked to lymphoma. That's just the impact of one night of four hours of sleep. You could perhaps imagine the circumstance or the state of your immune system after weeks, if not ye...

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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