Sunshine and Melatonin (and your sleep cycle)
It’s now common knowledge that nighttime exposure to computer, tablet, and TV screens sabotages sleep —the light they emit simulates sunlight, thus suppressing sleep hormones. There are even special glasses that you can purchase pretty cheaply on Amazon that block the most disruptive light wavelengths.
However, plenty of daytime sunlight is vital for good sleep, and most of us don’t get near enough.
Research shows the average person spends less than an hour a day outside. Compare this to our ancestors that would literally spend all day outside.
For shift workers it’s even worse. So for all you firefighters, nurses, police officers and whoever else on those night shifts, thank you, but prob best to leave those shifts to the young ones.
That lack of exposure to sunlight inhibits production of melatonin, a hormone that triggers the sleep cycle and puts us to sleep. Also remember that Serotonin is converted into Melatonin.
So if you have a serotonin deficiency (think depression) it can make it even more difficult to get a good nights sleep. Now your tired, depressed and can’t sleep. And the cycle continues in a wonderfully perpetual cycle of never-ending torture. But, thankfully there is help!
A Finnish rat study observed one group living under fluorescent lighting (hmmm - sounds like just about every person in America right. Living in our little work boxes inside our bigger building boxes. We drive from our living box to our gym box to our shopping box to our work box, back to our house box. All to rinse and repeat the next day) Anyway, the other group was exposed only to sunlight through windows every day. While both groups received the same duration of both light and darkness during the study, the rats exposed to sunlight produced significantly more melatonin.
It’s not that the artificial light was detrimental. It simply wasn’t strong enough — the sunlight was more than seven times brighter than the fluorescent light. Nature knows best!
This is what boosted melatonin production. Researchers assert that variation of light throughout the day, from dawn to dusk, also supports healthy melatonin production. Basically, it is better to have a little variation in the strength of the light like the sun rising, mid day, and late afternoon sun as opposed to the constant light from your little boxes.
During a sunny day, lux levels (which measure the intensity of light) reach 50,000. Compare this to indoor lighting, which ranges in the low to mid hundreds at the most. For most of human history we have lived with natural light and it plays a significant role in the function of the body and brain.
Why melatonin and light rhythms are so important
Anyone who has suffered through insomnia and sleep deprivation understands the importance of sufficient and quality sleep. Generally we should get at least 6 hours but preferably 8 for most people. And getting naps is a great way to help make up for a sleep deficiency, as long as they aren’t too late in the day. A short 20 - 30 minute power nap is a great way to regenerate your lagging brain function.
However, melatonin and our sleep-wake cycle (also called circadian rhythm) are intertwined with every system in the body, affecting much more than how rested or tired we feel. Tons of studies point to the importance of a healthy sleep-wake cycle for overall immune, hormonal, and mental health.
Remember, our body is like a complex spiderweb. Everything is connect to one another. I talk about this in some of my other blogs.
For instance, one study found that women suffering from PMS show chronically low melatonin levels. Just two hours a day of exposure to sunlight increased their melatonin levels and relieved their symptoms.
A German study showed subjects with mood imbalances exhibited healthier serotonin levels after just one week of light therapy. And there are some pretty cheap options for some light therapy products. Check out the link for the most common light therapy lamp I recommend in my office.
Another study showed subjects experienced a 160 percent increase in melatonin at night after just a half hour of exposure to bright light from a light box.
How to get enough outdoor light in an indoor world
It’s not easy getting enough sunlight when you’re indoors all day working or going to school. But it’s vital for healthy sleep, brain function, and metabolic function to get enough light exposure. As long as its the right type of light.
Some solutions are obvious —
1. Spend as much time outside as you can (my personal favorite, but not always feasible). Eat lunch outside and go for a walk on your breaks. Maybe you can even work outside on your laptop if your job is portable. This is what I do when I’m working on patient files on my non patient days.
2. If possible, work near windows that get plenty of natural light. One study showed employees working near a window received twice as much light as their coworkers who didn’t and hence enjoyed more sleep.
3. If sufficient exposure to natural light isn’t possible, indoor light therapy has been shown to help relieve sleep and mood imbalances. Again, check out my link to my favorite lamp. You want to get one that is 10,000 Lux
Look for a light box that delivers plenty of lux and is big enough for sufficient exposure. The Center for Environmental Therapeutics provides criteria for purchasing a reliable light box, which they recommend using for at least a half hour in the morning. I often recommend doing 2 - 30 minute sessions per day. Or, just leave it on all day.
So let your light shine on!
I’m Dr. Craig Mortensen
Be Healthy, be happy!