Is Blue Spectrum Light A Savior Or Monster?
The sun emits ultraviolet rays that can boost vitamin D levels in the body through skin exposure but causes skin damage if that exposure is excessive. Similarly, the sun emits visible light, the light that allows you to see things. When you run visible light through a prism, it fractionates into light waves comprising every color of the rainbow.
The red waves are at one end of the spectrum (low intensity and long wavelength) while on the other end of the spectrum are blue waves (high energy and short wavelength). Because of its high energy, the blue spectrum of light is the most impactful to mood and sleep with indirect exposure to the open eye needed to impact serotonin and melatonin.
Our circadian rhythm
Your body’s natural day and night cycle (called circadian rhythm) direct the orchestrated release of hormones vital for optimal health. Since antiquity, the cues for the circadian rhythm has come from exposure to sunlight during the day and a lack of sunlight at night.
A couple of hours before you normally wake up, your body is slowly increasing the amount of adrenaline (called epinephrine) in your blood to get you ready to start the day. An hour before bed, your body is putting melatonin into your blood to prepare you for sleep. If you ever woke up at 2 am to feed a baby and administer a diaper change, you know that your body is not prepared and you feel awful.
In modern times, we have interfered with the body’s circadian rhythm by staying indoors and closing out the sunlight during the day while exposing ourselves to artificial light from TVs, computers, smartphones, and tablets at nighttime. The biggest negative manifestations of altering the normal light/dark cycle includes depressed mood and trouble sleeping. Both of these states can have longer-term health consequences such as accidents, obesity, high blood pressure, and cardiovascular disease.
How the blue spectrum helps
The blue spectrum of visible light can help address problems resulting from inadequate sunlight exposure during the day. People with depression, especially seasonal affective disorder (depression that worsens during the winter months when the hours of sunlight per day are low) frequently feel better when they use a therapeutic light-box (called phototherapy) for 20-60 minutes a day in the morning. This tells the body that nighttime is over and that it is time to get geared up for the day. It also helps set the biological clock for when it needs to start releasing melatonin at nighttime.
Finally and most importantly, it enhances the production of serotonin in the brain. For seasonal affective disorder, people will start therapy in the late fall and continue until mid-spring. Other people use phototherapy for only a few days to alleviate jet lag and acclimate to the new time zone they are visiting. This phototherapy is different than the ultraviolet therapy used for psoriasis. Ultraviolet light exposure will not alleviate depression symptoms.
Getting the right exposure
Unfortunately, exposure to blue waves of visible light at bedtime can keep people awake. Blue light, in particular, can suppress melatonin release, suppress sleep inducing delta waves in the brain, and decrease the amount of REM sleep people get. Chronically suppressing sleep increases the risk of heart disease, makes it harder to concentrate, and lowers serotonin concentrations. In addition, the blue light waves cause more glare making it harder for people to see properly when directly exposed. For these reasons, the American Medical Association is concerned about some newer streetlights and car headlamps that emit a greater amount of blue light.
So what can you do? Try to get exposure to the sun (preferred) or a therapeutic light-box for 20-60 minutes each day, preferably in the morning time. Keep the windows open for some time each day to let natural light shine on you. If you have streetlamps outside your window, get light blocking shades and pull them down at nighttime so that light doesn’t interfere with your sleep. At 30-60 min before bedtime, try not to use electronics.
If you cannot avoid technology at nighttime, use nighttime modes that diminish blue wave exposure or wear special glasses that shield the eyes from blue light rays. This will make the picture less clear and have a redder color hue. By managing your exposure to blue light, you can manage one of the many negative effects of the modern world on your health.
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