The Roman Empire had laws guaranteeing people's access to sunlight in their homes.
The Greeks used light to build solariums for healing. They knew that light was important for the fortification of bones and treatment of jaundice in infants – methods we still practice today. The Greek physician Hippocrates even used sunlight to treat rickets, obesity, metabolic disorders, and to cauterize wounds.
In the 1860s, Florence Nightingale taught her nurses about the importance of being exposed to fresh air and sunlight during convalescence.
Flash forward to today where 93% of our time is spent indoors. Sadly, we find people supplementing their diets with the so-called sunshine vitamin, vitamin D, rather than spending more time outside.
And healers of all sorts still recommend light therapy – in many forms – to treat a variety of ailments... For instance, photobiomodulation therapy – which targets the regenerative properties of cells in the body.
Turns out, the body has three pathways by which it uses light: through the eyes and vision, through a non-visual optic path, and via photobiomodulation...
Light enters the eyes through the cornea. The cornea then bends the light in such a way that allows it to pass through the pupil – which is in the center of the iris. The light then reaches the eye's crystalline lens, which focuses the light rays for our retina. The retina captures the light like the film of a camera does and processes the input into impulses that are sent to the optic nerve.
Light reaches the eye via the non-visual optic pathway as well. This happens by way of non-visual photoreceptors in the eye. These cells tell your brain that there is light present without you having to actually "see" it.
Photobiomodulation occurs when the mitochondria in our cells are exposed to and subsequently absorb light. This absorption produces cellular energy and allows the cell to perform its various functions.
This chart below shows all the possible treatment targets using photobiomodulation therapy...
Essentially, light can be used to help you regrow hair, heal wounds, reduce pain, and even rejuvenate the skin.
Light therapy is commonly used as a treatment for seasonal affective disorder ("SAD"). SAD is a form of depression that occurs as the result of lost sunlight exposure during the winter months. SAD is generally experienced as moodiness and the loss of energy. More than 10 million people in the U.S. experience SAD.
To counteract the lack of sunlight received during the dark winter months, people use light therapy lamps at home or in the office. This technique is called bright light therapy. Spending just 20 minutes a day sitting in front of a sun lamp is known to have great effects on people's mood and levels of depression.
Bright light therapy mimics the sunlight through a lamp. Spending 15 to 30 minutes in bright light – at least 10,000 lux – stimulates your retinas, which then activates the hypothalamus. The hypothalamus then regulates your circadian rhythm (your sleep-wake cycle). The exposure to bright light also stimulates the production of melatonin (also used in the circadian rhythm cycle) and regulates the use of serotonin (which regulates your mood).
A 2020 study published in the Public Library of Science found that bright light therapy is also an effective treatment for bipolar depression. A total of 12 studies were included in this meta-analysis and a total of 847 patients with bipolar depression were examined.
Bipolar depression involves extreme mood swings and can include symptoms of fatigue, disinterest, weight loss, insomnia, hopelessness, and even suicide attempts. Using bright light therapy to treat bipolar depression usually yields quick results, whereas many medicines can take a month to build up in the system enough to have an effect.
Bright light therapy has been found to be an effective treatment for people with Parkinson's disease who are experiencing sleep disturbances and depression. It also has been shown to improve motor function in people with Parkinson's.
Additionally, bright light therapy is helpful for people experiencing panic disorder or post-traumatic stress disorder ("PTSD") and who are also being treated with exposure-based cognitive behavioral therapy.
While we have fantastic technology these days to use light to our advantage, getting full spectrum natural sunlight is still very important. Here are ways we can practice getting more good light to support our general health and well-being...
1) Use halogen or incandescent bulbs – they are the closest to broad spectrum daylight.
2) Avoid fluorescent and compact fluorescent lamp ("CFL") bulbs – because they are prone to flickering, emit UV radiation, and contain mercury vapors that can escape if the bulbs are broken.
3) Choose "warm white" light emitting diode ("LED") bulbs – using them will minimize the effect of harmful blue light. You can find these warm whites at the grocery store or online – wherever you're buying your bulbs. Household LEDs generally are sold at 6 watts.
4) Avoid fluorescent and LED bulbs with excessive flickering – they cause unnecessary stress.
5) Avoid light sources in your bedroom at night, especially electronics.
6) Spend as much time as possible outdoors in daylight, especially in the winter.
7) Expose yourself to daylight without your glasses or contact lenses on. Letting the light hit your eyes without a barrier allows for better absorption of the sun's rays.
The great news is that spending time in the sunlight is a very low risk activity. Some risk is associated with being exposed to ultraviolet light – which in large enough doses is linked to skin damage, retina damage, and accelerated aging over long periods of time. Otherwise, being bathed in the light of the sun is essential to your health and well-being.
Not only will you be healthier, but you will find yourself happier as well. Afterall, they don't call it a "sunny disposition" for nothing.
What We're Interneting...
- Why sunlight is actually good for you.
- Something different: Afternoon naps mean better mental agility.
Here's to our health, wealth, and a great retirement,
Dr. David Eifrig and the Health & Wealth Bulletin Research Team
February 2, 2021