Yes, Light Is A Form Of Medicine: Here's Why + The Dosage You Need

In terms of light, much of the conversation tends to focus on quantity, not quality. We know that getting some vitamin D from sunlight is crucial, and baking in the sun for ages does quite a lot of harm in the long run. But in terms of the types of light itself? You might not give it a second thought.

Well, according to New York Times bestselling author Max Lugavere, we should start using different types of light to our advantage. In fact, light is a form of readily available, no-cost medicine, and it's crucial for our sleep, cognitive function, and (as it turns out) our immune systems. But as with most aspects of well-being, it's all about balance. "Light is either a form of medicine, or it can potentially accelerate aging," he says.

As a general rule, you want to get some bright light into your eyes when you wake up in the morning, says Lugavere. Not only does it help you wake up and feel less groggy (the dreaded "sleep hangover" is no joke), but that morning light has actually been shown to promote brain-healthy neurotransmitters. "Getting bright light in your eyes in the morning puts the brakes on melatonin release, and it's been shown to boost serotonin in the brain, which is involved in having a healthy mood and cognitive function," Lugavere explains. 

That boost of bright light in the mornings also balances our circadian rhythms, which as we know is significant for many other processes in our body (including immune health). By getting that bright, natural light into our eyes first thing in the morning, Lugavere says we can set our circadian clocks, even if you're spending your day mostly indoors. 

According to Lugavere, you need a light intensity of 1,000 lux or brighter to anchor your circadian clock and reap the health benefits. While that number sounds pretty large, rest assured that it only takes about half an hour of natural light to reach the threshold. 

As Lugavere notes, light has a huge impact on our sleep—and, transitively, our health. "Bright light at the end of the day can have an opposite effect," he explains. Meaning, while light may be considered a form of medicine, when used at the wrong time it can have the opposite effect, he says. That's not to say you need to wear an eye mask everywhere you go once the sun goes down; dim light is totally fine. After all, "A hunter-gatherer would be exposed to a campfire and the moon and stars in the sky," Lugavere notes. That dim light won't reach 1,000 lux, so it shouldn't be cause for alarm. 

What does reach 1,000 lux is that artificial, fluorescent light we expose ourselves to every time we watch Netflix or scroll through social media before bed. According to Lugavere, that's the type of bright light that interrupts our circadian rhythms: "By exposing your eyes to extremely bright light at night, you're actually pumping the brakes on melatonin at the time of the day when you want melatonin to be properly expressed. That's how light can act as a pro-aging agent," he says.