Why Light Matters - Part Three: Why You Need Darkness To Be Healthy

In nature, daylight is only half of the recipe for a healthy circadian rhythm and high-quality sleep - the other half is darkness. 

Darkness is the key signal in your evening environment that directs your brain to wind down and produce large amounts of your key sleep hormone melatonin.

Melatonin is the hormone that creates the condition for your body to experience high-quality sleep, and because of this, it also affects the function of virtually all of the other hormones and neurotransmitters in your body.

Your ability to produce high amounts of melatonin directly impacts every area of health including your weight, mood, appetite, digestion, metabolism, immune system, muscle growth, libido, sleep and much more... 

It can't be emphasised enough how important it is that your body is able to produce as much melatonin as possible at nighttime if you want to be a healthy and happy human being.

The amount of melatonin that you're able to produce is directly proportional to the quality of your sleep, your mood and your overall health.

More darkness after sunset = more melatonin = a longer and happier life

Now... it's crucial you understand that once the sun sets outside, all forms of natural blue and green light (that were given off in high amounts by daytime sunlight) disappear from view until the sun rises the next day. 

Blue light, and to a lesser extent green light, stimulate your brain and prevent it from calming down, producing melatonin and preparing for sleep. 

This makes perfect sense because you want to be energised during the daytime when the sun is full of blue and green light, and you wouldn't want to be producing melatonin and falling asleep... which is why these types of light begin to disappear in the hours leading up to sunset.

For millions of years, the only types of light that we were able to access after sunset were red, orange and yellow frequencies (the colours of fire).

These are much less energetic wavelengths of light that have a far smaller impact on our circadian rhythm and melatonin production. 

The problem is we aren't living outdoors under nature's laws anymore. We're now in control of the type of light that we're exposed to in our environment at night.

This is empowering once we begin to responsibility for our nighttime light exposure.