It wasn’t long ago that a surgeon might stroll into the operating room with a lit cigarette in tow, as some lauded nicotine’s beneficial effects on focus and attention, but the CDC now considers tobacco use the leading cause of preventable death worldwide. Trans fats used in fast foods were considered a healthy alternative to saturated fats, until further research linked them directly to heart disease. Soda was once thought to be an innocent source of enjoyment and even health benefits, yet scientists today tie the beverage to our obesity and diabetes epidemics.
In the 1800s, Thomas Edison championed his famous light bulb saying it “is in no way harmful to health, nor does it affect the soundness of sleep.” Unfortunately, more than a century later, a growing amount of scientific research is showing otherwise. The light bulb may indeed be the next popular, pervasive and seemingly innocuous innovation proven to be toxic.
Electric light in its various forms — including LEDs, fluorescent and incandescent lights — is increasingly viewed as a root cause of our nation’s epidemic of sleep and circadian rhythm disorders. By enabling, encouraging and even enforcing a 24/7 lifestyle, the constant stream of texts, emails, articles and videos at the palm of our hands has placed us at higher risk for the myriad consequences of poor sleep: obesity, diabetes, heart disease, stroke, depression and attention deficit disorders.
As Dr. Charles Czeisler, head of sleep medicine at Harvard Medical School and Brigham and Women’s Hospital put it in May’s edition of Nature, “Technology has decoupled us from the 24-hour day to which our bodies evolved.”
Human beings evolved in an environment guided by the rise and fall of the sun. Our physiology adapted to optimize our neurological, hormonal and metabolic processes around this basic light/dark pattern. We would feed in the day and sleep at night. This cycle is embedded in our natural body clock, or “circadian rhythm,” Latin for “around the day.” Since the industrial revolution and rapid spread of artificial light, most developed countries have paid less attention to this ancestral cadence.
What happens when this basic pattern gets disrupted? MIT professor Leonard Guarente is proving that a poor circadian rhythm is linked to less successful aging and shorter life span. Last year, he and his team published a study in Aging Cell showing that mice with a strong circadian rhythm “enjoyed nearly 20 percent longer life spans than their littermates.”
Dr. Guarente’s team published a follow-on study in Cell revealing that SRT1, a gene known to be critical for health maintenance and disease protection, plays a key role in managing the circadian rhythm. Mice with high levels of SRT1 protein maintain circadian function longer, while others experience a decline in circadian function as they age. The researchers conclude that SRT1 may confer its health benefits by protecting the circadian clock — providing evidence that the lack of synchrony between our physiologic processes and the light/dark cycle are central to the aging process. “We are proving circadian rhythm is high up on the list of requirements for health maintenance,” says Dr. Guarente.
Satchin Panda, associate professor at the Salk Institute and UC San Diego demonstrated the power of the circadian rhythm in a breakthrough study published in Cell Metabolism. While many nutritionists still advocate “calories in versus calories out” for weight loss, Dr. Panda and his colleagues showed that eating throughout the 24-hour day significantly increases weight gain and incidence of chronic disease, compared to eating the same number of calories during a more biologically appropriate time frame (i.e. sunrise to sunset). Dr. Panda’s team concluded that preserving natural feeding rhythms is an extremely cost-efficient lifestyle intervention “that can prevent obesity and its associated metabolic disorders.”
A study of nearly 27,000 men by the Harvard School of Public Health published July in Circulation, echoes Dr. Panda’s conclusions. Researchers showed that eating late at night increases risk of heart disease by 55 percent. When you eat may be just as important as what you eat, since it appears that our bodies process food less optimally when digested during hours that run counter to our evolutionary biology.
It has long been known that night-shift workers experience a higher incidence of obesity, diabetes, heart disease, stroke, mental health issues and many types of cancer. Are they the canaries in the coalmine? With the ubiquity of electric light, and U.S. adults averaging more than eight hours a day of screen time, most of us are becoming what scientists call “social shift workers” — lured into socially behaving like night-shift workers by smart phones, TVs and the like.
Given the ubiquity of the problem — up to 70 million Americans suffer from some type of sleep disorder – and the fundamental importance of sleep, the morbidity toll from electric light may indeed prove to outweigh cigarettes, trans fats and soda combined. “This is a public health crisis,” confirms Dr. Guarente. The dangers posed by an environment inundated with artificial light may similarly require significant public awareness efforts to properly address. Perhaps we can begin by labeling 3:00 AM texts, calls and emails toxins in the form of second-hand insomnia.
Royan Kamyar, M.D., MBA is founder and CEO of Owaves