How much sunlight do you get on a daily basis? Are you regularly exposed to the morning sun, or are you stuck inside a car or underground subway on your way to work? When you’re out and about, do you wear sunglasses to block out the sun’s natural light?
With so much emphasis on skin damage and anti-aging, many people don’t think about the importance of sunlight for our physical health. However, light exerts a major impact on your stress system. That’s right, the light you expose yourself to, both inside and outside, has a dramatic impact on your resiliency and, ultimately, your overall health and performance. In fact, sunlight is the most important stimulus for re-tuning your cortisol rhythm, the ultimate “health hack” to upgrade your resiliency and overall health.
Is Artificial Light Overriding Your Natural Circadian Rhythm?
If we look back to our Paleo ancestors about how light impacts our health, two things really stand out. First, in the evening hours, hunter-gatherers did not have access to external light sources and thus did not stay awake much past sunset. They definitely didn’t stay up watching movies on their laptops or diving into some ice cream while relaxing in a room lit up with artificial light from lamps, TVs, and computers. Second, they woke up with the morning sunlight. There was no snooze button or cup of coffee on hand to give them a morning boost. The sunlight from the morning sunrise was the natural boost to get them up and ready to attack the day.
The presence of artificial light and the stimulus it triggers in your sympathetic “fight or flight” nervous system can hinder your ability to fall asleep and stay asleep, and ultimately reduce your sleep quality.
Sleep quality is just as important as sleep quantity, and too much artificial light at night may be a key factor leading to inadequate recovery and increased stress on the body. Exposure to WIFI at night stimulates your nervous system in a similar way, impairing your deep sleep and leaving you with poor energy upon rising, hitting snooze multiple times, or struggling to get out of bed.
The Hormonal Impact of Nighttime Light
As we expose ourselves unnaturally to excessive amounts of evening light sources, our health suffers. Shift workers are the classic example used in research studies to determine the impacts of reduced natural light exposure. What do these studies find? Shift work, or inadequate exposure to natural light is associated with increased risk of various cancers, cardiovascular disease, blood sugar dysfunction, and weight gain.
How does this affect you if you’re not a shift worker? If you expose yourself to too much light at night – via lights in your room, televisions, or laptops – it inhibits the production of your sleep hormone, melatonin, which is supposed to increase naturally in the evening to promote deep sleep. If you blunt melatonin output with excessive light or WIFI stimulation, it can lead to difficulty falling asleep, difficulty staying asleep, and ultimately decrease output of growth hormone (GH).
GH has been dubbed the “fountain of youth” hormone for its incredible ability to recharge and revitalize the body – increasing lean muscle, improving immunity, and enhancing mood, just to name a few things it does. If you put the brakes on your melatonin and GH output from too much light, it will lead to inadequate recovery during sleep and reduce your resiliency to stressors during the day (i.e. when training or at work).
The Different Types of Natural Light
There are three types of ultraviolet light: A, B and C. The ultraviolet A and B lights are essential for your health and the reason why exposure to direct sunlight is crucial for your health and resiliency. Unfortunately, clouds block out the beneficial A and B ultraviolet lights. Ultraviolet light C, on the other hand, is damaging to your health and normally blocked out by the ozone layer in the sky. If you get a sunburn or burn easily, you can blame ultraviolet light C for the damaging effects.
Different colors in the light spectrum elicit a different impact on your brain, body, nervous system and health. Blue light is especially problematic, suppressing melatonin production at night, and therefore your capacity to rebuild and recharge during deep sleep.
How do you get exposed to blue light? Sources of blue light include sunlight, digital screens (TVs, computers, laptops, smartphones and tablets), electronic devices, and fluorescent and LED lighting. A recent study showed that almost two-thirds of the population spends at least 6 hours in a front of a computer screen daily. Other potentially harmful effects of excessive blue light exposure include headaches, blurry eyes, and increased risk of diabetes, heart disease and depression.
Which Light Is Best at Night?
Red lights exert the least impact on melatonin production and are therefore best to use in the evening at home. Pick one lamp or light source in your den or family room and replace regular light bulbs with red light bulbs to help your body ease into the transition from the stressful sympathetic dominant “fight or flight” mode during the day, to the relaxing “rest and digest” parasympathetic recovery mode at night. (Warning – you may want to close your curtains so the neighbors don’t get the wrong idea!).
Also, do your best to avoid the stimulation from laptop or TV screens 30-60 minutes before bedtime. If you really struggle with falling asleep or waking up through the night, extend this to 90-120 minutes before bedtime as your nervous system may be more sensitive to light exposure.
What About The Morning – Which Light Is Best?
In the morning it’s important to expose your eyes to the first morning sunlight. The light from the sun interacts with the receptors in your eyes to naturally raise cortisol levels, giving you the energy to get up and go! Ideally, your cortisol levels should naturally be high in the morning (your cortisol rhythm), waking you up from deep sleep and preparing you for the day. If you hit snooze multiple times, struggle to get out of bed, or desperately need your coffee kick, then you’re in a need of a “tune-up”. Start your day by opening the curtains and exposing your eyes to the morning light to help re-tune your natural daily cortisol rhythm.
Unfortunately, wearing sunglasses blocks out most of this natural sunlight. Try walking into work without wearing your shades, or at the very least giving yourself 5 minutes of exposure to the morning light. You will start to feel the improvement in energy in no time!
If you’re a busy person “burning the candle at both ends,” exposure to first morning sunlight and minimizing evening exposure to blue light sources like laptops and TVs is critical for rebuilding your body’s resiliency. Take the time to create the right environment at home for optimal recovery and you’ll see the effects on your performance at work and in the gym in no time.
Dr. Marc Bubbs ND, CISSN, CSCS