Some everyday medical facts are believed to be “golden rules”, but in fact they are probably incorrect. A recent article in the British Medical Journal lists some of the “consensus” medical myths. Myth 1: Fingernails and hair still grow after death Truth: At first, many doctors thought this idea was correct, but after in-depth analysis, they realized that this is not possible. When a person dies, the skin of the body dries out and the skin tissue, especially the skin, shrinks. Therefore, when the skin dries out the nails appear more prominent, and similarly when the skin shrinks the hair appears longer, and the loss of nutrients to the roots makes the hair much fluffier. Myth 2: You should drink at least 8 glasses of water a day Fact: Dr. Rachel Mevereman, a pediatrician at the Indiana University School of Medicine, says, “There is no medical evidence to suggest that people have to drink this much water every day!” According to Verriman, this view may have its origins in the 1945 recommendation of the Nutrition Association that people should consume eight cups (equivalent to 64 ounces) of fluids per day. Years later, the 8 cups of fluid recommendation evolved into 8 cups of water. Fruits and vegetables also contain a lot of liquid water in people’s daily diets, so if you have to drink 8 cups of water a day, that’s a bit of an overkill in fluid intake. Myth #3: We only use 10% of our brain Fact: Magnetic resonance imaging (MRI) scans, positron tomography (PET) scans, and other imaging studies have shown that there are no areas of the brain that are still asleep, or even individual nerves or cells that are inactive. This latest research reveals that metabolic studies of chemical processing processes in brain cells show no non-functional regions in the brain. Dr. Aaron Carroll, associate professor of pediatrics at the Indiana State University School of Medicine, said the idea that “only 10% of the human brain is used” originated in the early 20th century, and that this view may have been motivated by the desire to encourage self-cultivation and to stimulate the brain’s full potential. Myth 4: Frequent shaving of body hair will make it grow faster, thicker and darker Fact: A clinical study conducted in 1928 comparing the growth rate of body hair in shaved and unshaved areas of the skin showed that hair in unshaved areas of the skin was not darker or denser, and did not grow as fast. A number of recent studies have confirmed that when body hair is shaved, it grows at the top of a thicker root and looks thicker as it continues to grow. And the late development of body hair is thicker and darker mainly depends on the level of sunlight exposure. Myth 5: Reading in dim light is detrimental to vision Truth: Through the study of a large number of patients, ophthalmologists have confirmed that reading in dim light will produce significant eyestrain characteristics, but this feature is transient, and will not have a lasting impact on visual function. Observations of if dry eye patients have also found that reading in dim light only causes transient eye tension, and the symptoms disappear immediately after stopping reading. In fact, it is not difficult to imagine that long before the invention of electric light, human beings have been reading in candlelight, kerosene lamps and other dim lighting equipment, at that time did not produce a large number of myopic people. Today, I am afraid that the increase in the number of myopia is still related to the length of time and frequency of reading. Myth 6: Cell phone signals have an interfering effect on hospital equipment Fact: In 2002, a U.S. government website published a story that medical instruments in an intensive care unit injected patients with large amounts of adrenaline for no apparent reason because of cell phone interference. Since then, a medical journal has attributed 100 medical errors since 1993 to cell phone interference, a conclusion that became common belief after a full-page article in the Wall Street Journal emphasized that cell phones can cause medical errors by interfering with signals from hospital equipment. In fact, there has never been a documented case of a patient dying because of cell phone signal interference with medical equipment, and there have been virtually no documented cases of equipment malfunction, false alarms, etc., caused by cell phones. The most relevant is a British study that concluded that cell phones had a 4% interference effect on medical equipment within 1 meter of the equipment, with 0.1% of the effect being more pronounced. Also, in 2005, the Ogilvy and Mather Clinic in the UK conducted a survey: 510 tests on 16 medical devices and 6 cell phones showed that there was significant interference in 1.2% of cases. Similarly, tests in other European countries had similar conclusions, i.e. that there could only be interference within 1 meter. A new study from 2007 again puts the case for cell phones in perspective: in 300 tests in 75 wards, cell phones did not interfere with medical equipment at all under normal use. On the contrary, another survey showed that doctors who carried cell phones to clinics greatly reduced the risk of delays in patient care due to miscommunication.