People’s Health

 Without a medical degree, sorting medical fact from fiction can be daunting: does reading in the dark actually hurt your vision? Do we really use only 10 percent of our brains? It turns out that even MDs have difficulty with widely held medical maxims like these. A study in the British Medical Journal’s December issue looked at seven medical myths that doctors often accept as truth. "The problem is that a lot of people take what [doctors] say as gospel, but sometimes it’s not backed up by science," says Aaron Carroll, an assistant professor of pediatrics at the Regenstrief Institute in Indianapolis and co-author of the study. "Patients and parents should feel free to ask about why the things they are being told are true. They should be upfront about it." To start your year off with a little less fiction and a little more fact, here are seven of the most common medical myths debunked:

1. Reading in dim light ruins your eyesight.

While this is one myth that parents around the world have loved for generations, it has very little scientific backing. Reading in the dark can cause a temporary strain on the eyes, but it rapidly goes away once you return to bright light. The practice has been blamed for increasing rates of myopia (nearsightedness), but Carroll says those claims don’t align with the evidence—we’re living in the best-lit conditions the world has ever seen. "Seventy years ago we were reading by candlelight and weren’t going blind," says Carroll. "There’s no evidence for this whatsoever."

2. Using cell phones in hospitals is dangerous.

Despite the signs in most emergency waiting rooms, studies have found little to no significant cell phone interference with medical devices. In 2005 the Mayo Clinic ran 510 tests with 16 medical devices and six cell phones. The incidence of clinically important interference was a mere 1.2 percent. A 2007 study on cell phones "used in a normal way" found no interference during 300 tests in 75 treatment rooms.

3. Fingernails and hair grow after death.

"Growing hair and fingernails is a very complex hormonal task," says Carroll, one that can’t happen after one has died. So how did this myth get off the ground? It could be because after death the skin begins to contract, which could give the appearance that the nails are growing.

4. We use only 10 percent of our brains.

The notion that our brains are not running at full speed simply doesn’t hold up. "Numerous types of brain imaging studies show that no area of the brain is completely silent or inactive. Detailed probing of the brain has failed to identify the ‘nonfunctioning’ 90 percent," Carroll and Rachel Vreeman, an assistant professor of pediatrics at the Indiana University School of Medicine, write in the British Medical Journal study. Carroll says the notion may go as far back as the snake-oil salesmen of the early 20th century, who used the myth to sell a tonic that would increase brainpower.

5. You should drink at least eight glasses of water a day.

The source for this myth may be a 1945 article from the National Research Council that claims that a "suitable allowance" of water for adults is 2.5 liters a day, although the last sentence of the article notes that much of that water is already contained in the food we eat. Existing studies suggest that that often-omitted fact is key to understanding water intake. We get enough fluids from our typical daily consumption of juice, milk and even caffeinated drinks. And drinking too much water can cause water intoxication, a severe electrolyte imbalance in which cells swell with excess fluid, and even death.

The Nurses’ Health Studies are among the largest and longest running investigations of factors that influence women’s health. Started in 1976 and expanded in 1989, the information provided by the 238,000 dedicated nurse-participants has led to many new insights on health and disease. While the prevention of cancer is still a primary focus, the study has also produced landmark data on cardiovascular disease, diabetes and many other conditions. Most importantly, these studies have shown that diet, physical activity and other lifestyle factors can powerfully promote better health.

The NHS is just one of many that’s studied the effects of working the night shift only to find there is a strong link between obesity, cancer, reproductive health problems, mental illness and gastrointestinal disorders and working the graveyard shift.

Big surprise? Not to me.

I’ve linked my working the graveyard shift to my development of CFS. If you read my book, The Complete Idiot’s Guide to Fighting Fatigue or this blog you know that I believe it’s the cumulative effect of stressors over time that so weakens and disrupts your central nervous system, your adrenals, and your immune system that you’re unable to cope with any demands and you essentially crash and burn.

Working the graveyard shift is an enormous unnatural stressor due to the disrupted circadian rhythms and chronic sleep deprivation.

Because the evidence for an increased cancer risk is so strong, in December 2008 the International Agency for Research on Cancer, a unit of the World Health Organization, declared that shift work is "probably carcinogenic to humans."

Graveyard work is now in the same category as carcinogens like diesel engine exhaust, anabolic steroids, and ultraviolet radiation. We’re not meant to be exposed to light at night because it suppresses the physiologic production of melatonin, a hormone that has antiproliferative (cells that grow wildly out of control) effects on intestinal cancers. The lack of endogenous melatonin is also related to Alzheimer’s disease, glucose intolerance, and impaired immune function.

Animals that have their light-dark-day-night schedules switched develop more cancerous tumors and die earlier. Now we know that women working the night shift over many years are more prone to breast cancer and there’s evidence that men working at night may have a higher rate of prostate cancer.

People used to think it was a ridiculous notion that smoking caused cancer. Today people are failing to connect other unnatural stressors and toxins like sleep deprivation, the obsessive use of fragrance and chemicals so widely used in personal care and household products, and the chemicals and other biologically injurious substances added to processed foods to illness and disease. They don’t see how you can’t stress the body in unnatural ways year after year without terrible consequences.

I WISH that someone would have told me years ago when I was valiantly trying to work nights and not getting any sleep that it would lead to my CFS and my having to exit my work and my life. I didn’t know that I couldn’t mind over matter it. Yes I was SICK with sleep deprivation but I thought if I could just get through it I could move on when I got off of nights. But that stressor was so enormous to me that it caused an ingrained and lasting sleep disorder and it was an added weight on top of all my other stressors.

I can’t tell you how many doctors I told, "I used to do 50 mile bike rides and then go work a double shift in intensive care." I was trying to emphasize to them how healthy I had been and how it didn’t make sense that I had gotten so ill. I also talked about my inability to sleep and working the night shift. Although on top of this I was very thin NO BELLS AND WHISTLES WENT OFF and I never had a doctor sit me down and tell me how my behaviors and lifestyle were the cause of my illness because doctors aren’t looking at imbalance. Instead they look at things like your labs and listen to your breath sounds and heart in order to determine if you’re sick. If someone came to me now and told me any of that I would tell them, "You have sleep deprivation, you are obsessively exercising in a way that is unhealthy, you are too thin to be working that hard both exercising and at work. Those are the reasons you are sick." Then I would tell them what to do to get well.

If you work nights and you are suffering with chronic fatigue, continual disrupted sleep patterns even while not on the night shift, and you begin to feel unable to deal with other stressors its time for you to re-evaluate whether whatever work you’re doing is worth the risk of developing CFS.

Cancer aside, CFS takes away your life and is extremely difficult to recover from. Working nights is hazardous to your health and like all things if the risks outweigh the benefits then it’s not worth it.