Early detection and intervention needed
1. The circadian rhythm of a modern man
“In 1910, the average American slept nine hours a night, disturbed only by the occasional Model T backfiring. We now average 7.5 and declining.” – Robert Sapolsky (Why Zebras Don’t Get Ulcers)
The typical Western person’s circadian rhythm differs in at least three main ways of which the human species has adapted to in its history
First of all, the amount of light during night time. Before artificial lighting popularized, people spent the night in almost complete darkness . Today, most families live in almost constant light even if it is pitch black outside.
Second, the amount of light during the day is now lower than it has ever been in human history . The reason is that we do not spend much time outdoors. We spend the days indoors, where the amount of light can be over a hundred times less than the amount of light outside.
“Bright light can help shift even the most extreme body clocks,” says Professor Roenneberg. “But the amount of light in most offices is laughable. You would be lucky to get 400 lux [a unit of measurement of the intensity of light] at a bright vertical office window during the day, whereas outside on a cloudy day in summer you would experience more like 10,000 lux. If it’s a blue sky, you could get as much as 150,000 lux.” (Independent: Could you be suffering from ‘social jet lag’?)
The third current problem is sleep duration, which has been decreasing in recent decades.
In a study on connections between sleep and obesity published this year, it was found that in the 1960’s people slept about 8-9 hours a night. By 1995, the amount had shrunk to seven hours. In 2005, a third of the population slept for about six hours a night. Actigraphic and polysomnographic studies show that middle-aged people only get six hours of sleep on average. (Reiter et al. 2011)
Now we are going to speculate the effect of these on health by studying some research material on the subject.
2. The circadian rhythms’ connection with health – shift work and clinical sleep studies
People doing shift work is an interesting group when reflecting on the circadian rhythms’ effects on health. These people must for follow a very unnatural sleep rhythm because of their profession. Epidemiologic data shows that certain health problems are much more common among shift workers than in the average population.
“If light were a drug, the government would not approve it,” says Professor Charles Czeisler of the Harvard Medical School. And Professor George Brainard of Thomas Jefferson University in Philadelphia, adds: “Humans evolved on a planet without electric light over thousands and thousands of generations. The body is designed to be alert and awake during daytime hours and to sleep at night. Now we have a 24-7 society that isn’t in harmony with our biological design.”
“In the new study, scientists grafted human breast cancer tumours on to rats and infused them with blood taken from women during the day, in the early hours of the morning, and after being exposed to light at night. The blood taken in darkness slowed the growth of the cancers by 80 per cent, but the blood taken after exposure to light accelerated it.” (Independent: Avoid breast cancer. Sleep in the dark…)
If even a few years of shift work can clearly be seen as an elevated risk for breast cancer, could a lifetime of sleep deprivation or other light related problems that affect most people have an effect on the risk of chronic disease? I would say it’s possible.
Some experimental studies have been done, in which for example the test subjects duration of sleep has been reduced.
3. The environmental light and melatonin secretion
Next we’ll dive into the world of melatonin, but first the basics.
The ambient light contributes significantly to the body’s circadian rhythm. In particular, blue light (460-490nm) inhibits the pineal gland from secreting melatonin. Melatonin is often called the dark hormone, because it is secreted at night.
Only blue light affects the secretion of melatonin, so if a person is wearing blue blocker sunglasses, melatonin secretion will not be affected. Of course, removing the short wavelengths (blue light) from lamps will have the same effect. (Sasseville et al. 2006, Kayumov et al. 2007, Chellappa et al. 2011).
Even normal lighting before going to sleep can decrease melatonin secretion which can have effects on health. The melatonin blocking effects of blue light can be significant especially in winter time, when the small amount of daytime exposure to light can cause the body to react more significantly to bright artificial light used in the evening. (Gooley et al. 2011, Higuchi et al. 2007, Park&Tokura 1999).
Below are empirical studies in which the amount or type of light has been altered and the results have been documented:
I believe that the effect seen in the bright light study mentioned before could be replicated and possibly surpassed with ordinary daylight. Expensive bright lights shine light at 10 000 lux at the best, but outside the amount of light can be ten times larger. Daylight might also have other benefits like vitamin D production caused by UV-radiation, the temporary lowering of blood pressure caused by nitric oxide metabolism, plus the stress-relieving effects of red and near-infrared light. The problem of course is, that in the winter time natural light isn’t available in large amounts in all parts of the world. (Holick et al. 2007, Opländer et al. 2009, Feelisch et al. 2010, Barrett&Gonzalez-Lima 2013).
Melatonin can also be used as medication and in clinical trials it has been portrayed as quite a useful drug:
Even though light is very important influence to human / animal circadian rhythm, apparently among light, food, other people and physical activity also have a notable effect. I’m not yet particularly familiar with that data, so it will not be discussed in this essay.
4. Tips for improving sleep and health
Get some light after waking up and during the day
The effect of light on the circadian rhythm seems to be the largest immediately after waking up, so walking outside for ten minutes after waking up can be beneficial.
If you want an adequate amount of blue light during the winter, there are roughly two types of light therapy lamps. Large ones and small ones. The larger lamps have a large lux amount (they are brighter), and the smaller ones compensate with the light spectrum and by a smaller distance between the user and lamp. The lights of small lamps are slightly bluer to compensate for the smaller intensity of light. (Meesters et al. 2011)
I have noticed that if I don’t get enough light during the first 1-2 hours after waking, I’ll stay more or less sleepy for the rest of the day.
Sufficient blue light during the day might be important for alertness, mood and sleep. (Viola et al. 2008)
A light box (left), blue blocker sunglasses (right).
Avoid unnecessary light during the late evening
Turning lamps off and dimming your computer’s display are some of the simplest non-pharmaceutical ways to increase melatonin levels at night. And to make it easier to fall asleep.
If I get a too much light into my eyes at bedtime, I will suddenly become very alert and that means that I need to wait another 1-2 hours until I’ll be able to fall asleep. When I was in high school, this was a significant problem for me. I had to wake up at 7am on almost every morning, yet I usually couldn’t fall asleep before midnight. The late evening, the time when I should have been already sleeping, was the most productive time of the day, because of the strong alerting effect of light at night.
F.lux is a popular computer program that changes the displays color to orangish automatically in the evening. Personally I prefer to use Gamma Panel (gapa.exe), a program that allows you to remove blue light completely from your computer screen.
The blue blocker sunglasses are another alternative. If you want to block out blue light, you can buy some nice lenses from ebay (use keyword “aviator blue blocker”) and wear them in the evenings.
Also red light bulbs (LED) can be used can be used as night reading lamps.
Poor curtains can leave the room too bright during the night or early morning. A sleep mask is an easy and cheap way to correct this problem.
In the evening, I usually use Gamma Panel software to redden my computer screen. This makes falling asleep much easier.
Nutrition and sleep
A combination of melatonin, magnesium and zinc has been shown to have great results in sleep quality studies. (Rondanelli et al. 2011)
In a few studies, glycine has been shown to improve quality of sleep. The primary source of glycine is collagen protein or gelatin. This means that head cheese and bone broth are a good source of glycine and can improve quality of sleep. I occasionally make jelly out of gelatin and concentrated juice. (Yamadera et al. 2007, Inagawa et al. 2006)
I personally agree with the basics of Matt’s “Eat for Heat” ideology. If I have trouble falling asleep, I try to eat some extra starch and fat calories (e.g. rye/wheat bread with butter and cheese) and avoid too large amounts of fluid.
Here’s a list of things that, according to Roberts’ experiments, could benefit those having problems related to their diurnal rhythm.
A mirror, to see my own face during my piano improvisations. (Seth Roberts’ faces therapy)
Thanks to Laura Mikkonen for doing most of the translating work.
There’s an art to napping.
Studies have found different benefits—and detriments—to a nap’s timing, duration and even effect on different people, depending on one’s age and possibly genetics.
“Naps are actually more complicated than we realize,” said David Dinges, a sleep scientist at the University of Pennsylvania’s Perelman School of Medicine. “You have to be deliberative about when you’re going to nap, how long you’re going to nap and if you’re trying to use the nap relative to work or what you have coming up.”
A snooze on the couch on a Sunday afternoon may seem like the perfect way for a responsible adult to unplug. But at a time when roughly one-third of people report not getting enough sleep, more naps, albeit short ones, might make for a more functional workforce, researchers say.
Sleep experts break sleep down into several stages, which the brain cycles through roughly every 90 to 120 minutes. These stages are broadly characterized into non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. NREM is further broken down into stage one and two, which are considered light and intermediate sleep, followed by slow-wave sleep. Awakening from slow-wave sleep, the deepest kind, results in what doctors call sleep inertia or sleep drunkenness: that groggy feeling that can take awhile to shake off. Finally, there’s REM sleep, often associated with dreaming.
Sara Mednick, an assistant psychology professor at the University of California, Riverside, said the most useful nap depends on what the napper needs.
For a quick boost of alertness, experts say a 10-to-20-minute power nap is adequate for getting back to work in a pinch.
For cognitive memory processing, however, a 60-minute nap may do more good, Dr. Mednick said. Including slow-wave sleep helps with remembering facts, places and faces. The downside: some grogginess upon waking.
Finally, the 90-minute nap will likely involve a full cycle of sleep, which aids creativity and emotional and procedural memory, such as learning how to ride a bike. Waking up after REM sleep usually means a minimal amount of sleep inertia, Dr. Mednick said.
Experts say the ideal time to nap is generally between the hours of 1 p.m. and 4 p.m. Napping later in the day could interfere with nighttime sleep.
The body’s circadian rhythms help people to expect to be awake in the morning and early in the night. “So if you take naps when your brain doesn’t expect to be sleeping, you feel kind of thrown off,” contributing to the sleep inertia effect, said Rafael Pelayo, a clinical professor at Stanford University School of Medicine’s Sleep Medicine Center.
A telltale sign of being very sleep-deprived, he said, is dreaming during a short nap. “Definitely in a 20-minute nap you should not be dreaming,” he said.
Ilene Rosen, an associate professor of clinical medicine at Penn’s Perelman School of Medicine, said the ideal duration of a nap is still being debated, but generally speaking the “10-to-20-minute nap is really the optimal time in terms of bang for your buck.”
Leon Lack, a psychology professor at Flinders University in Australia, found in a 2006 study in the journal Sleep that among shorter breaks, 10-minute naps packed the most punch.
The study compared naps ranging from 30 seconds to 30 minutes, testing 24 participants at each of several intervals. After each nap the individuals were tested on a variety of mental-processing tasks. The sharpness of the 10-minute nappers became apparent “right away,” Dr. Lack said, and remained apparent for about two to 2 1/2 hours.
Those who took 20- and 30-minute naps tended to feel groggy immediately after the nap for up to about 30 minutes. From there, they showed mental sharpness similar to what researchers saw from the 10-minute nappers, with that sharpness lasting a bit longer.
Jonathan Brandl is a Newton, Mass.-based consultant who works from home. Up at 5 a.m. to hit the gym, he finds himself fading around 2 p.m. His solution is a fast snooze in a comfy chair in his den. His trick for waking up: He holds a pen or pencil in his hand, which usually falls about 10 to 15 minutes into his nap, waking him up.
“After the nap, I feel totally refreshed and then power through the rest of the day,” the 56-year-old Mr. Brandl said.
Though napping at work often remains taboo, experts say growing scientific evidence of its benefits has led select workplaces to accept it.
Christopher Lindholst, chief executive and co-founder of New York-based MetroNaps, has installed specially designed sleeping pods for Google, Huffington Post, an Iowa construction company and the Arizona Diamondbacks baseball team. The chairs retail for $8,995 to $12,985.
The 60-minute nap may not be kosher in most workplaces, but it also has its pluses.
In a 2012 study in the journal Neurobiology of Learning and Memory, researchers split 36 college-aged students into three groups. Each group learned a memory task, pairing words on a screen with a sound. Afterward, one group had 60 minutes to nap, another 10 minutes. The final group didn’t sleep.
Upon retesting, the napping groups fared better, as expected, said Sara Alger, lead author of the study and a postdoctoral research associate at the University of Notre Dame.
More interesting, she noted, was that on further testing, including a week later, the 60-minute group performed far better than the 10-minute group, which now performed as poorly as the non-napping group. The researchers concluded that slow-wave sleep—only experienced by the 60-minute nappers—is necessary for memory consolidation.
Researchers continue to explore why some individuals don’t seem to benefit from naps. Dr. Mednick said ongoing studies are looking at potential genetic differences between habitual and nonhabitual nappers.
Kimberly Cote, a professor of psychology and neuroscience at Brock University in St. Catharines, Ontario, said individuals who don’t normally nap tend to slip into the deep stages of sleep more quickly than those who do. Studies have found through monitoring brain waves that regular nappers are good at maintaining a light sleep when they nap and show better performance improvements than their non-napping counterparts.
“We’re not sure what those individual differences are,” she said, “if that’s something that they’ve learned to do over time or if there’s something biologically different that allows them to nap like that.”
Another trick to waking up perky after a short nap is to drink a cup of coffee before sleeping. Caffeine won’t hurt such a short break and should lessen the effect of sleep inertia.
Dr. Dinges recommends sleeping partially upright to make it easier to wake up. Studies, he said, have found that not lying totally flat results in avoiding falling into a deeper sleep.
“A lot of people say, ‘I only need four hours of sleep a night.’ There’s a few of them around but not very many,” he said.
Write to Sumathi Reddy at firstname.lastname@example.org
A version of this article appeared September 3, 2013, on page D1 in the U.S. edition of The Wall Street Journal, with the headline: A Field Guide to the Perfect Nap.
The NY Times jumped into the sleep-related media fray with a feature that addressed the flip side of sleep—waking up. Reporter Katie Thomas reports that the FDA is taking heightened interest in the issue thanks to new evidence that suggests the effects of well-known sleep drugs could persist into the day.
Of particular interest is a possible link between sleep drugs and car accidents. With studies showing about 60 million prescriptions for sleep aids in the United States last year, the problem (if it exists) could be widespread.
The NY Times points out that relative newcomers such as Intermezzo from Purdue Pharma could help pave the way for appropriate dosing guidelines. In 2011, the FDA recognized gender variability when it approved the sleep drug Intermezzo, which treats patients who wake up in the middle of the night.
Women get a lower dose of Intermezzo (active ingredient Zolpidem) and all users are warned to only take the drug if they have four hours or more of bedtime left. “The agency’s experience with Intermezzo,” writes Thomas, “along with other research, led it to order in January that the dosage for all drugs containing zolpidem — the active ingredient in Intermezzo, as well as Ambien and related generic sleep drugs — be halved for women.”
Despite the increased scrutiny for sleep drugs, the NY Times highlighted the inherent paradox of the sleep drug/sleepiness situation. “What we have to weigh here is that people who don’t sleep well are a hazard on the road because they do fall asleep while driving,” said Robert Voas, a senior research scientist at the Pacific Institute for Research and Evaluation and an expert on driving safety in the Times article. “There’s risks on both sides.”
Source: NY Times
Everyone has a favorite sweet spot on their bed. You can’t drift off into a blissful snore-filled sleep until the pillow has been adjusted to a perfect 63-degree angle, and your arm is placed in that one nook under the blanket. It may be hard work getting there, but it’s totally worth it.
Despite all that, however, you’re still sleeping wrong. There’s something better out there for you.