Light Exposure

Following on from sleep, I wanted to touch upon light. And this is something that many people might not think about when it comes to hormonal health. But light exposure is really crucial for so many functions in our body, and in our modern environments we have become very disconnected with natural daylight and are spending so much more time indoors, exposing ourselves to so much more artificial light, especially artificial blue light. Even the type of lights, in terms of light bulbs, have changed in the past couple of decades. And this is actually to the detriment of our health as well. Light exposure is really important to understand because it can influence so many things. We talked earlier about how the light we’re exposed to impacts our circadian rhythm — that internal biological clock that tells us what time of day it is. And so, if we are out of sync with the natural light outside throughout the day, our body’s going to be really confused. That’s going to obviously have an impact on our sleep later at night. But that chronic exposure to artificial light — and also the lack of daylight — is going to impact our cortisol levels, especially if we’re exposing ourselves to blue light at times of the day when blue light shouldn’t really be that prevalent. In the natural world, we have different types of light throughout the day. You might have heard of some of these already, especially because there are a lot of devices now that try to mimic this — when you can just actually go outside. But anyway, I digress. In the morning, when we wake up at sunrise, the dominant type of light in the sky is red and infrared light. Red and infrared light have actually been shown to be really healing to many areas of our physiology. They’re important for our mitochondria, which are the energy-producing powerhouses in our cells. You might have seen red light devices being sold, or red light masks for skin health. Red and infrared light are really potent, powerful healing light. This light is most prevalent around sunrise — you can see it in the color of the sky. As the morning progresses, red and infrared light start to decline and we start to have more blue light in our days. Around solar noon, it’s a lot of bright blue light, but it has different wavelengths — it’s not the same as the blue light from a lamp shade or our computer screens. As the day goes on, the blue light reduces, and as we get closer to sunset, the red and infrared light come back. The lack of light at night helps us to fall asleep and sleep through the night. That is the natural cycle of the day. But in our modern world, we’ve bypassed that. We wake up in the morning and we’re exposed to bright blue light from our phones, which is basically like midday sun. So if you’re waking up and the first thing you do is switch on your phone, it’s sending that message to the body that it’s midday, and your body’s like, “Hang on a minute — we haven’t had time to slowly ramp up our cortisol levels.” You’re basically shot out of a cannon from the moment you wake up. We don’t want that, because the cortisol that gets prioritized first thing in the morning from being exposed to blue light from our phones or overhead lighting takes away from progesterone and pregnenolone production to make cortisol. So it’s a hormonal disaster waiting to happen. It’s also going to impact blood sugar as well. Light exposure influences cortisol levels, it influences the hormone leptin — which we talked about earlier — the satiety hormone. Leptin also influences progesterone production and ovulation. If this is dysregulated — and leptin is very light-sensitive — that’s going to impact hormones and satiety levels. That’s why people who do shift work can really struggle from a metabolic point of view. I’ve seen clients who were shift workers struggle with fertility too, because it can dysregulate hormones. Light exposure also impacts insulin levels. Spending a lot of time in bright light at night can affect insulin and blood sugar and actually increase blood sugar. The combination of staying up late in front of the TV and snacking makes this worse. Jack Kruse once said that light exposure is actually worse than the snack itself when it comes to blood sugar and insulin resistance. And then obviously, if we’re exposing ourselves to bright light at night, melatonin isn’t produced adequately. Melatonin starts to get produced toward the end of the day to help us fall asleep. If it’s being suppressed by artificial light at night, that’s going to impact our sleep. Melatonin also impacts ovarian follicles and has been shown to influence follicle-stimulating hormone, endometrial receptivity, and even fertility outcomes — as seen in IVF research. So light exposure influences everything from our blood sugar, stress hormones, reproductive hormones, satiety hormones, and insulin. Obviously, we can’t go back to living in a little house on the prairie and just having candles — although I do have candles in my house in the evenings during winter. But I know it’s not realistic for everyone, and we live in a modern environment where we’re exposed to blue light throughout the day through screens, phones, and overhead lighting. So what can we do to offset this without having to go back in time? Here are a few tips to optimize your light environment if you’re able to. And again, I don’t want this to add to your to-do list — just small, feasible things that make you feel good. A lot of people who start doing this see real shifts in mood as well. Getting up with sunrise exposes your eyes to red and infrared light first thing in the morning. That primes your body and circadian clock, and even your skin. Red and infrared light are crucial for mitochondrial production — the energy cells, the batteries of your cells that make up your tissues, organs, and you. If you’re able to see the sunrise, that’s amazing — and it’s a massive mood lifter if you do it regularly. If not, then as we said earlier, get outside first thing in the morning — open a window, look at the sky, go outside if possible. Even better, because we have light sensors on our skin, not just our eyes. Avoid glasses or contact lenses first thing in the morning and get outside for as little as a minute or as long as you can — the longer the better. Maybe you can journal outside, have your morning hot water and lemon outdoors, sit in stillness, take your dog for a walk — whatever’s feasible for you. Throughout the day, try to spend some time outside, especially if you’re working on screens. Take breaks to step outside for a few minutes to reset your body clock. Eating outside has been shown to help with insulin regulation and blood sugar balance too. You can go deep into this — there are apps like My Circadian App where you can see, depending on where you are, when daybreak, sunrise, UVA, and UVB occur. UVB is great for vitamin D production, and UVA is great for hormonal health — usually about an hour after sunrise. In the evening, we want to wind our lights down along with the sun — following that natural rhythm. As we approach sunset, dim the lights. After sunset, avoid blue light exposure as much as possible. It’s not always easy, so do what you can. You can buy light bulbs that don’t emit blue light, dim your lights, use candles, or enable filters on your devices to turn screens red. Blue light blocker glasses — usually dark orange or red — can also make a massive difference. I noticed it with my daughter when I changed her night light to a red light with no blue light. She reads with it and falls asleep much better. She uses blue light blockers at night too if we’re watching TV. It’s not about being perfect, but being aware and following the natural rhythm as best you can. In winter, it’s trickier because it’s darker in the mornings and nights, but just be mindful of blue light exposure and how much time you spend outside. Even a few minutes outdoors can have a massive impact on cortisol levels, hormones, blood sugar balance, insulin, and sleep. These are just some ideas — and we’ll put them all into practical action.