Using Red Light to Improve Metabolism & the Harmful Effects of LEDs | Dr. Glen Jeffery

**Andrew Huberman** (0:00)
Let's talk about indoor lighting, because I am very concerned about the amount of short wavelength light that people are exposed to nowadays, especially kids.

**Glen Jeffery** (0:08)
This is an issue on the same level as asbestos. This is a public health issue, and it's big. And I think it's one of the reasons why I'm really happy to come here and talk, because it's time to talk. When we use LEDs, the light found in LEDs, when we use them, certainly when we use them on the retina, certainly looking at mice, we can watch the mitochondria gently go downhill. They're far less responsive. They, their membrane potentials are coming down. The mitochondria are not breathing very well. You can watch that in real time.

**Andrew Huberman** (0:44)
Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life.
I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. My guest today is Dr. Glen Jeffery, a professor of neuroscience at University College London. In today's episode, we discuss how you can use light, in particular red, near-infrared, and infrared light to improve your health. And no, not just by getting sunlight. Although we do talk about sunlight, Dr. Jeffery's lab has discovered that certain wavelengths or colors of light can be used to improve your skin, your eyesight, even your blood sugar regulation and metabolism. Dr. Jeffery explains how light is absorbed by the water in your mitochondria, the energy producing organelles within your cells, to allow them to function better by producing more ATP. He also explains how long wavelength light, things like red light, can be protective against mitochondrial damage caused by excessive exposure to things like LED bulbs and screens, which of course we are all exposed to pretty much all day long nowadays, and simple, inexpensive, and even zero-cost ways that you can get long wavelength light exposure, and again, not just by getting more sunlight. He explains that long wavelength light can actually pass into and through your entire body, and that it scatters when inside you. Now that might sound scary, but it's actually a great thing for your health, because that's how long wavelength light can improve the health of all your organs, by entering your body and supporting your mitochondria. Believe it or not, certain wavelengths of light can actually pass through your skull, into your brain, and help promote brain health. During today's episode, we also discuss new findings that correlate the amount of sunlight you're exposed to with longevity. Those are very surprising findings, but they're important. Also why everyone needs some UV light exposure. And we discuss whether it's important to close your eyes when using red light devices or in red light saunas, and how best to apply red light and things like infrared light in order to drive maximum health benefits. Today you're going to learn from one of the greats in neuroscience as to how to use light to improve the health and longevity of any and every tissue in your body and the mechanisms for how that works. Before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero cost to consumer information about science and science-related tools to the general public. In keeping with that theme, today's episode does include sponsors. And now for my discussion with Dr. Glen Jeffery. Dr. Glen Jeffery, welcome.

**Glen Jeffery** (3:14)
Thank you. Thank you very much.

**Andrew Huberman** (3:16)
We go way back. Later I'll tell a little bit of the story and why it is truly unforeseen that we'd be sitting here talking about what we're talking about. But it's great to see you again. And I'm super excited about the work you've been doing over the last few years, because it's completely transformed the way that I think about light and health, light and mitochondria. And frankly, every environment I go into now, indoor or outdoor, I think about how that lighting environment is impacting my cellular health, maybe even my longevity. So if you would be willing, could you explain for people a little bit about light as let's say the visible spectrum, the stuff that we can see and the stuff that's kind of outside what we can see as a framework for how that stuff impacts ourselves? Because I think without that understanding, it's going to be a little bit mysterious how it is that lights of particular colors, wavelengths as we call them, could impact our mitochondria the way they do. But with just a little bit of understanding about light, I think people will get a lot more out of our conversation.