Why morning sunlight exposure helps your sleep better
A couple of areas always top the charts when experts talk about health and longevity. Diet, exercise and sleep. Earthy30 is primarily about diet. However, after Level 1, we add 10 mins of morning sunlight and exercise into the equation for Level 2.
This piece is about the relationship between sunlight and sleep optimisation. If you’re someone who has a hard time getting to sleep, this blog is for you, offering a rationale for viewing morning sunlight, backed up with science popularised by famous neuroscientist, Andrew Huberman.
Using sunlight to set your circadian rhythm
Catching morning rays helps trigger a sequence of reactions that awaken your body. Specifically, each morning when we wake, we have a (healthy) spike in cortisol. Adding sunlight to the equation strengthens the spike and helps galvanise your body into action.
Once started, these reactions also set a stop time, some 16 hours later, which helps turn wakefulness into sleepiness through the secretion of melatonin. This daily dance between awakeness and alseepness is known as our circadian rhythm.
According to world renowned neuroscientist Andrew Huberman, catching morning sunlight in the first 3 hours of the ‘day’ (loosely before 10am) helps keep our circadian rhythm on track… If we spend a lot of time indoors, working late and not getting natural sunlight, our body clock can slip and we end up with a kind of mild jet lag.
Why does morning sunlight help wake us up?
Perhaps you’ve heard of the ‘golden hour’ or ‘red sky at night, shepherds delight’, two phrases that describe the colour of the sky.
This sky colour, and indeed the light all around us, changes throughout the day. In the middle of the day, the light is pure blue. However, in the morning and evening, the light has a more yellow/blue contrast.
The neurons in the eye - the melanopsin ganglion cells - are experts at detecting this yellow/blue contrast. Before 10am, if you catch morning sunlight, your eyes understand that it’s morning, helping spike cortisol and set your body clock. In this context you could consider your eyes to be more like ‘sensors’ than seeing apparatus.
You have to be outdoors for morning sunlight set your body clock
Aside from the colour of the light, the intensity of the light is important too. Huberman says, “The key is to view morning sunlight for 5-10 minutes on clear days, 10-20 minutes on overcast days, and 30 min on overcast days.”
Here’s why:
You’d be surprised how little light is given off by indoor lights compared to being outdoors, and how much more light you get when the sun isn’t diffused by clouds. Earthy30 did a fun test with an app called Light Meter where you can measure the intensity of light using your phone.
Light is measured in lux. 1 lux is the amount of illumination created by one candle, on a square metre of paper, one metre away.
You can see here the difference between a cloudy day and a bright one, measured in lux.
This is what 11,100 lux looks like
This is what 61,000 lux looks like
Morning sunlight and Earthy30
In Earthy30 Level 2, we encourage you to get 10 minutes of sunlight during the hour after waking. If you make this healthy habit part of your everyday morning routine, you’ll entrain your body to wake early up switch off in time for bed, helping with sleep - that essential pillar for longevity.
