Heart Disease and Light: What Top Docs Want You To Know
Heart disease is the leading cause of death for men and women. In the United States, one out of every four deaths is attributed to heart disease every year. Globally, nearly one-third of all deaths–17.5 million—were attributed to cardiovascular disease in 2012.
Fortunately, heart disease can often be prevented by making healthier choices. Exercising more, eating a healthier diet, giving up smoking—and turning out the lights at night all help.
Wait… What do lights have to do with heart disease? Well, as it turns out, a lot.
“As I demonstrate in my new book, The Plant Paradox, blue light is one of the Seven Deadly Disruptors to our health. In fact, many cardiologists and heart surgeons agree that Thomas Edison’s invention of the light bulb is one of the biggest causes of our current epidemic of heart disease, diabetes, cancer and dementia.” — Steven R. Gundry, MD, Medical Director of The International Heart and Lung Institute.
In fact, last summer, the American Medical Association actually issued a warning that high-intensity street lights may increase the risk of serious health conditions, such as cancer and heart disease.
Scientists aren’t sure why nighttime light exposure is so bad for us. But the fact that it disrupts our circadian rhythms, suppresses melatonin production and delays sleep are possible causes.
Light Has a Profound Impact on Your Body Clock
For most of mankind, humans rose with the sun and slept after dark. Sure, our ancestors probably hunted under the full moon and sang songs around the campfire. But for thousands of years, we lived primarily in darkness after the sun went down. As a result, our bodies evolved to actually require periods of light and dark.
The human body is a lot like a clock that needs to be reset every day. Every 24 hours, our circadian rhythm—or body clock—needs a signal from the external environment in order to stay in synch. As it turns out, the most powerful signals are periods of light and dark.
Periods of light and dark also influence hormone secretion, heart rate, alertness, sleep, body temperature—even gene expression. So, light’s impact on human health is far-reaching. Unfortunately, in our modern, 24/7 world, most people get too much light at night, which wreaks havoc with our health.
Let’s face it, many of us spend our evenings bathed in artificial lighting and basking in the blue glow from our TV screens. Unfortunately, these electric devices emit light of a blue wavelength that actually tricks our brains into thinking that it is daytime. This upsets our body clocks, makes it more difficult to fall asleep and suppresses melatonin production. And that’s a problem when it comes to your heart.
“…light at night is bad for your health, and exposure to the blue light emitted by electronics and energy-efficient light bulbs may be especially so…” — Harvard Medical School
Melatonin is Good for Your Heart
Melatonin is best known as the hormone that makes people feel sleepy. But it also has a number of beneficial effects on heart health. Melatonin:
- Acts as an anti-inflammatory
- Reduces tissue damage caused by strokes and heart attacks in animal research
- Lowers blood pressure
- Tunes down the sympathetic nervous system, which makes it easier to fall asleep
- Has antioxidant properties
- Reduces hardening of the arteries
- Effects both heart constriction and relaxation, and
- Reduces total cholesterol levels
Wow, who knew? But here’s the kicker: the pineal gland’s secretion of melatonin is stimulated by darkness and inhibited by light. So, spending your evening binge-watching Netflix in brightly-lit room actually prevents you from enjoying melatonin’s many beneficial effects.
It’s not a coincidence that patients with coronary artery disease have low melatonin production rates. Even more concerning, blood melatonin levels correlate with the severity of heart disease. The lower the melatonin level, the higher the risk of a heart attack and/or sudden death.
Sleep Your Way to a Healthier Heart
The melatonin effect may also be why poor sleep has been linked to heart conditions including high blood pressure, clogged arteries, heart failure, heart attacks and stroke.
“Sleep is essential for a healthy heart. People who don’t sleep enough are at a higher risk for cardiovascular disease—regardless of age, weight smoking and exercise habits.” — National Sleep Foundation
In fact, according to the American Heart Association, those who sleep less than six hours a night are twice as likely to have a stroke or heart attack than those who sleep six to eight hours. Unfortunately, one-third of American adults sleep six or fewer hours a day. That puts 40.6 million people at a higher risk for heart disease.
So why are so many Americans sleep-deprived?
According to Harvard Researcher Steve Lockley, Ph.D. “Light at night is one of the main reason people don’t get enough sleep.”
Michael Siminovitch, director of the California Lighting Technology Center at the University of California at Davis agrees saying, “As a species, we weren’t designed to see light at night.”
When You Eat Matters for Heart Health
Interestingly enough, when we eat also has serious implications for the development of cardiovascular disease, according to new a American Heart Association Scientific Statement. Like light exposure, eating and fasting help set our body clocks, which in turn regulates our metabolism. As a result, late-night snacking is linked to the development of cardiovascular disease, type 2 diabetes mellitus and obesity.
In mice, food consumed during a period when they were supposed to be sleeping disrupted their circadian rhythms. So eating three squares a day at regular meal times is probably best for keeping our body clocks in synch and preventing heart disease.
“When we eat reduces heart disease risk factors, including weight. Light shapes our circadian rhythm, which in turn influences our body’s response to habits like breakfast, late night eating, and fasting.” — Dr. Mehmet Oz
What You Can Do to Prevent Heart Disease
While eating regular, healthier meals, exercising more and giving up the smokes are all great steps for preventing heart disease, minimizing your exposure to light at night is equally important.
To keep your body clock in synch, support heart-healthy melatonin production and get a better night’s sleep, minimize your exposure to stimulating blue light for at least 60 minutes before going to bed. That means turning off the lights, shutting down your cell phone and sitting at least ten feet away from your TV.
“Do yourself and your heart a favor, eliminate blue light after dark. Switch to red and yellow spectrum bulbs. Wear blue-blocking wrap-around glasses at night while on the computer or watching TV.” — Steven R. Gundry, MD, Medical Director of The International Heart and Lung Institute
If sitting in the dark isn’t your thing–and hey, who can blame you, outfitting a lamp with a biologically-optimized LED light bulb that minimizes blue light spectrum is a great solution. These bulbs provide more than enough soft, white light for normal evening activities, such as reading a book or magazine, but still support the body’s natural production of heart-healthy melatonin. Circadian lighting also makes it easier for you to fall asleep–and to stay asleep–which is also great for heart health.