According to a CNet News, Health Net, January 13, 2011 news article, "Light at night linked to high blood pressure, diabetes," by Elizabeth Armstrong Moore, a new study accepted for publication in The Journal of Clinical Endocrinology & Metabolism, finds that exposure to electrical light between dusk and bedtime "strongly suppresses melatonin levels and may impact physiological processes regulated by melatonin signaling, such as sleepiness, thermoregulation, blood pressure, and glucose homeostasis."
Check out the abstract of the study, "Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans," published in the Journal of Clinical Endocrinoogy & Metabolism, published online, December 30, 2010 as doi:10.1210/jc.2010-2098.
Also, in the Sacramento and Davis area, the University of California, Davis is studying how a light at night in your room may link to cancer. See the article, Light at night linked to cancer by disrupting cell cycle. Too many people in Sacramento sleep with a computer, a cell phone, or a TV set turned on in their room, with flickering light and noise blaring from the TV or computer all night long as their only way to get to sleep.
Another study announced four months ago on September 2, 2010 from the Center for Interdisciplinary Chronobiological Research at the University of Haifa has found an additional link between Light At Night (LAN) and cancer. This research joins a series of earlier studies carried out at the University of Haifa that also established the correlation. "High power light bulbs contribute more to 'environmental light pollution', which the study has shown is a carcinogenic pollution," notes Prof. Abraham Haim, who headed the study. See the September 2, 2010 University of Haifa news release, "Light at Night and Cancer."
Watching TV in bed all night also has other health implications. Also see the article, Watching TV is cutting short your life. According to the article, for every hour of TV viewing, your risk of dying early from heart disease rises by 18 per cent, based on a study in Australia of sedentary lifestyle. The study reported that each hour of TV viewing also increases your risk of dying from cancer by nine per cent. In total, each hour spent in front of TV increases your risk of death by 11 per cent.
According to an article published on April 12, 2010 in Medical News Today, "Light At Night Disrupts Cell Cycle And Transcription Of Genes Linked To Cancer," based on a study, published February, 2010, in the scientific journal, Cancer Genetics and Cytogenetics, "Light pulses administered during the circadian dark phase alter expression of cell cycle associated transcripts in mouse brain," don't keep a light burning in your bedroom.
By turning on any any type of artificial light at night, for example, a TV left playing, a night light, or light streaming into a bedroom window from another room, the light disrupts the circadian cycle of cell division and affects transcription levels of genes that are associated with the formation of cancerous tumors and their spread. Keep your bedroom dark when you go to bed.
In the September 2, 2010 University of Haifa news release, "Light at Night and Cancer," earlier studies in which Prof. Haim has participated at the University of Haifa, have shown that people living in areas that have more night-time illumination are more susceptible to prostate cancer in men and breast cancer in women.
The researchers' hypothesis was that LAN harms production of melatonin, a hormone that is released from the pineal gland during the dark part of the 24h cycle and which is linked to the body's cyclical night-day activity and seasonality. When this hormone is suppressed, the occurrence of cancer rises.
The current study, in which Dr. Fuad Fares and Adina Yokler, Orna Harel and Hagit Schwimmer also participated, set out to establish or refute this hypothesis. In order to do so, four groups of lab mice injected with cancerous cells were examined: one group was exposed to "long days" of 16 hours of light and 8 hours of darkness, simulating exposure to artificial light beyond the natural number of light hours in a day.
A second group was exposed to the same "long days" but were treated with melatonin; a third group was exposed to "short days" of 8 light hours and 16 dark hours. And a fourth group was exposed to the same "short days" but during the dark hours was exposed to a half-hour interval of light.
The results show once again the clear link between LAN and cancer: the cancerous growths in mice exposed to "short days" were smallest (0.85 cubic cm. average), while those mice exposed to the interval of LAN during dark hours had larger growths (1.84 cubic cm. average) and those exposed to "long days" even larger growths (5.92 cubic cm. average).
The study also discovered that suppression of melatonin definitely influences development of the tumor. The size of tumor in mice exposed to "long days" but treated with melatonin was only 0.62 cubic cm. on average, which is not much different from the size of the growth in mice exposed to "short days". The study also found that the death rate in mice treated with melatonin was significantly lower than in those not treated.
The researchers say that their study results show that suppression of melatonin due to exposure to LAN is linked to the worrying rise in the number of cancer patients over the past few years. However, it is not yet clear what mechanism causes this.
"Exposure to LAN- disrupts our biological clock and affects the cyclical rhythm that has developed over hundreds of millions of evolutionary years that were devoid of LAN. Light pollution as an environmental problem is gaining awareness around the world, and the World Health Organization's International Agency for Research on Cancer (IARC) has already classified working the night shift as a higher grade of cancer risk," the researchers noted, according to the news release.
In the past year, researchers recently found links between sleeping or trying to sleep with a light on in your room at night and getting high blood pressure, depression, and cancer. Now the latest study focuses on the link between a light at night and its effects on blood pressure and diabetes.
Is your pineal gland calcified? And is the melatonin in your body scarce, which in turn, is causing you sleepless nights? The pineal gland between your eyes regulates your sleep/wake cycle. A tiny bit of your serotonin turns to melatonin. This melatonin that decreases with age is supposed to allow you to sleep in order to repair your cells and DNA. Melatonin's role is to promote a regular circadian rhythm, a biological clock of sleep and wakefulness.
You don't need your cell cycles disrupted by artificial light at night. Too much light in your bedroom at night also may be related to some types of cancer. Why does a light kept on at night cause chaos in the way your cells reproduce? It's because of light pollution. Add that to air pollution and toxins in your food and drinking water.
If you sleep with a night light on, it burns up your melatonin. If you sit more than five hours in front of a computer, it burns up your melatonin. If you take more than 3 mg of vitamin B12 in one day, it burns up your melatonin. The usual B12 dose is just 1,000 mcg. It's measured in mcg, not mg.
Exposure to bright lights at night burns up your melatonin so your cells can't repair themselves and you can't sleep. You don't want that happening--that is DNA repair problems which could lead to cancer. If you eat chocolate before bedtime, the caffeine and other stimulants in the chocolate keep you awake.
So does exposure to electromagnetic fields from cell phones and computers. So does sitting in front of a TV set for hours watching movies in your bedroom when you can't sleep. Is your TV set close to the foot of your bed?
Other ways to decrease the melatonin in your body include taking NSAID drugs, taking SSRIs, anxiety medicines, drugs to control high blood pressure such as beta blockers, steroids, or alcohol. Also don't exercise within 3 hours of bedtime. What can you do? Eat foods high in melatonin such as whole oat groats, corn, brown or black rice, Japanese daikon radishes, tomatoes, barley, or bananas.
Since bananas slightly raise your serotonin levels, they have a good chance of also raising a small amount of your melatonin levels. Don't forgot to brush your teeth after the bananas.
There are some drugs that actually raise melatonin levels, in addition to taking a small amount of melatonin. But since it may not be controlled or regulated as much as you'd want it to be, you'd have to know whether the supplement really had melatonin in it and how much. Tests show melatonin levels varied among a variety of brands.
Medicines that help raise melatonin levels include most MAOIs, St. John's wort, which may raise melatonin levels, and the drug desipramine. But why take drugs to raise your melatonin when you can just eat foods that raise your melatonin or take a melatonin supplement, if your doctor says it's okay with your own health condition.
You still have to watch for drug interactions with melatonin. For more information on melatonin, check out the article, "Treating and Beating Fibromyalgia," by Rodger Murphee, DC, CNS, published in the November 2010 issue of the Townsend Letter.
Artificial light at night may disrupt your cell replication
An artificial light at night disrupts the way your cells replicate, according to the latest studies. Scientists have recently found an additional link between Light At Night (LAN) and cancer.
Habitually, many people fall asleep watching the TV or a computer screen after midnight only to wake up suddenly, stirred by the light or when a blaring commercial on the TV begins those clicking sounds that suddenly bring the brain to attention. Too many people either work the night shift because that's the only job they can find or sleep with the TV or night lights on.
Don't disrupt your biological clock and cell cycle at night by sleeping with a light in your room or leaving the TV on while you sleep. Light at night may be linked to cancer. If you work the night shift, there's also a higher risk of cancer, according to the World Health Organization's International Agency for Research on Cancer (IARC). See the organization's website for information on its database on worldwide links in the environment to cancer.
Many people are afraid to sleep at night without a light on. Others go to bed with the TV on, with lights blaring as a way to distract their thoughts, dull their mind, and put them to sleep. But as you sleep with that light or TV screen on, the chronic light reduces the ability of your body to make melatonin. The result is a chronic light suppression of melatonin.
It's still a hypothesis, but scientists keep looking for links between increasing the risk for certain types of cancer by sleeping with a light on, any type of night light or light from a TV playing or a computer screen and its effects on your melatonin receptor genes, which have been linked to type 2 diabetes.
You'd have this same reduction of melatonin at night if you're a shift worker exposed to indoor light at night over the course of many years. Check out the life span of nurses who work for many years on the night shift.
Some nurses studied in the past were further predisposed to cardiac events and a shorter life span if they worked for many years on the night shift. And hospitals at night have bright lights or night lights where they staff works. Compare this to the routine of some medical students doing their residency after medical school who can grab a nap while on night duty.
Is the room where they can nap once in a while filled with light, even a night light? But medical residencies don't last for many years. And how many physicians work permanently on night duty for decades in emergency rooms without switching to day shifts?
Then take a look at factory workers and other employees who work at night for years, including those in the military, security guards, radio talk show personalities working at night, and the police who may be on night duty for decades working long hours. Researchers need to study the health issues of all types of night workers.
See the articles, Scientists Finding Out What Losing Sleep Does to a Body, and Sleep Duration, Health, and Performance. The same effects might also apply to factory workers and anyone working all night for many years, including bus and truck drivers or people working all night in various eateries.
The hormone melatonin is produced (at night, or now it seems, in darkness) by the pineal gland in the brain. It plays a role regulating the sleep-wake cycle and also in lowering blood pressure and body temperature. Of course, more research needs to be carried out. Check out the CNet News article, "Light at night linked to high blood pressure, diabetes," for further details of the latest study.