Circadian Biology: The Engine of Life
Think for a moment about how human life has changed over the course of just a few hundred years. Modern humans have roamed the earth for over 200,000 years. For most of that time they were hunter gatherers, with agricultural societies arising only about 10,000 years ago. For most of that time humans lived with only fire for light and heat. They were able to adapt to a wide range of climates and environments, and these environmental adaptations drove our evolutionary history. They lived according to the rhythms of night and day, and the seasons of the year. They spent most of their time outdoors in some form of physical activity, and adapted to times of feast and famine.Contrast that with most of modern humanity; we spend most of out time indoors, and are largely sedentary. We live in climate controlled environments, with artificial lighting. We are pretty much disconnected from our evolutionary roots, and are paying the price with our health. Physiologically, we are designed to follow the daily rhythms of light and dark, and this circadian cycle plays a big role in everything from hormonal balance, sleep, energy production,and coordination of most body functions. Natural light from the sun is what powers our circadian biology, and has a huge influence on our health and well-being. There is mounting scientific evidence that living under artificial light is harmful in many ways. Artificial light is very different from sunlight as it has much more blue light in its spectrum. Overexposure to blue light has been shown to decrease melatonin production thereby disrupting sleep. This is confirmed by the fact that insomnia has now reached epidemic proportions, with more that 10% of the US population taking prescription drugs for sleep. That in turn has a cascade of deleterious effects on our health. See my blog on Digital Dementia for more information about the effects blue light on our brains.Now researchers are finding increasingly that an out-of-phase circadian rhythm is a health hazard. “Maintaining synchronized circadian rhythms is important to health and well-being,” says Dieter Kunz, director of the Sleep Research and Clinical Chronobiology Research Group at Charité–Universitätsmedizin Berlin. “A growing body of evidence suggests that a desynchronization of circadian rhythms may play a role in various tumoral diseases (cancers), diabetes, obesity, and depression.”
Shift workers, whom Kunz calls “a model for internal desynchronization,” are known to experience increased morbidity and mortality for a number of diseases, including cardiovascular disorders and cancer. In fact, in 2007, the World Health Organization decreed that shift work is a risk factor for breast cancer, and on that basis, in 2009, the Danish government began compensating some female shift workers with breast cancer.
We've become almost phobic about the sun, and the widespread use of sunscreens may not be as beneficial as commonly believed. We have an epidemic of low Vitamin D, which predisposes us to lowered immunity, colon and breast cancer, hypertension, osteoporosis and a host of other health problems. Vitamin D is not really a vitamin, but a steroid hormone, and has a powerful influence on our biology. Maximizing your intake of Essential Fatty acids is very helpful to your circadian biology. It protects your eyes and skin from the harmful effects of sunlight. The light receptors in our eyes have high concentrations of DHA which transforms light to electrical signals that control most biological functions, even down to the mitochondria at a cellular level which produce our energy. The best source of DHA is fatty fish like sardines, mackerel, and salmon. If you don’t like fish, a good krill oil supplement like CVO from Systemic Formulas will work. We carry this in our office and I recommend taking 1-2000 mg./day.
What you can do
Use dim red lights for night lights. Red light has the least power to shift circadian rhythm and suppress melatonin. Use amber or red light bulbs or candles for light after dark.
Avoid looking at bright screens beginning two to three hours before bed.
If you work a night shift or use a lot of electronic devices at night, consider wearing blue-blocking glasses or installing an app that filters the blue/green wavelength at night (Flux or Iris).
Expose yourself to lots of bright light during the day, which will boost your ability to sleep at night, as well as your mood and alertness during daylight.
Early morning sun exposure resets your hormonal rhythm by stimulating the hypothalamus, which is our "hormonal control tower".
Exercise out doors whenever possible.
Spend more time outdoors without glasses or sunglasses. Wear a hat to shade you eyes instead.
Make sure you avoid all trans-fats and processed oils. Take a good quality Omega 3 supplement like CVO. We carry this in our office.
Read my blog on sleep.
To paraphrase Dr. Jack Kruse, a neurosurgeon and circadian biology expert: We should emulate the Sphinx, facing east in the morning with our bare feet on the ground.