Light
- Summary
- Problem: Not Enough Light in the Morning
- Solution: Light Therapy Lamps
- Problem: Too Much Light at Night
- Solution: Blue Light Reduction
- Problem: Vitamin D Deficiency
- Solution: More Vitamin D
- Note: Color Temperature
Summary
Get plenty of bright light in the morning and afternoon. Limit light exposure (especially blue light) in the evening before bed. If you live in a northern latitude, consider taking a vitamin D supplement.
Problem: Not Enough Light in the Morning
Humans need to be exposed to light during the day. When bright light hits the retinas it breaks down melatonin, kickstarts wakefulness, and resets our circadian rhythm. Due to modern lifestyles (being indoors) and varying weather conditions (cloudy days) many of us don’t get the required morning light exposure which leads to grogginess, insomnia, and depression1.
Solution: Light Therapy Lamps
The minimum effective dose for light therapy is considered to be white light at the cornea of 2,500 lux for 2 hours or 10,000 lux for 30 minutes1.
For reference, typical indoor lighting is 300-500 lux, an overcast day is 1,000 lux, and being outside on a sunny day is >10,000 lux2.
Schedule and climate permitting, the best way to get this exposure is to spend time outside (without sunglasses)! However, for those of us who live in miserable, cloudy areas the next best thing may be a light therapy lamp. This light therapy lamp is the one I have used for the past year while working on my computer in the mornings, and it has helped tremendously.
Problem: Too Much Light at Night
Artificial light and digital screens flood our eyes with light well past sunset. This additional artificial light prevents the release of melatonin which keeps us awake and lowers the quality of our sleep. All light does this to some degree, but the blue wavelengths of light are particularly bad.
Solution: Blue Light Reduction
-
Avoid digital screens and bright light 1-2 hours before bedtime. Reading paper books is a good substitute.
-
Wear orange glasses 1-2 hours before bedtime. You’ll look like a dork but they’ll reduce some of the blue light entering your eyes.
-
Color temperature software - most modern operating systems (Windows, MacOS, iOS, Android) have a built-in feature to adjust the color temperature of your display at night, reducing blue light output. Look in your display settings for a feature called “Night Light” or “Night Shift” or similar. Third-party software like f.lux also exists.
-
Take a melatonin supplement 1 hour before bedtime. Higher doses are not better - start with 0.5 mg to 3 mg.
Problem: Vitamin D Deficiency
When the UV rays in sunlight hit skin it promotes the synthesis of vitamin D3. Spending most of our lives indoors, living in a northern latitude in the winter, having the skin completely covered by clothing or sunscreen all reduce the amount of vitamin D our bodies generate. Given these factors, vitamin D deficiency is extremely common and can lead to problems with inflammation, immunity, mood, and bone health4.
Solution: More Vitamin D
-
If you live in a sunny climate close to the equator, go outside! 30 minutes of full-body exposure (without sunscreen) a few times a week is thought to be sufficient. Obviously use moderation here - for any longer than 20-30 minutes at a time you should be wearing sunscreen - the goal is NOT to give yourself skin cancer!
-
You can try to obtain as much vitamin D through your diet as possible, but this is notoriously difficult given that most foods (cod liver oil excepted) only contain minimal amounts of vitamin D4.
-
Take a vitamin D + vitamin K supplement. Aim for 2,000 - 4,000 IU of vitamin D per day. Adequate vitamin K intake is also helpful so as not to calcify the arteries.
Note: Color Temperature
Light with a high color temperature (e.g. a cloudy day ~7000K) tends to look more blue and feel “cooler”. Light with a lower color temperature (e.g. candlelight ~1900K) tends to look more orange and feel “warmer”.
The unpleasant character of florescent lights is due to a high color temperature. Many people (myself included) find interior lighting with a lower color temperature much more enjoyable to be around. Pay attention to color temperature when shopping for light bulbs. Modern specialty LEDs exist which have a low color temperature (~2200K) and feel warm like traditional incandescents.