Here is some news you can use. First off, Torbjörn Åkerstedt, a sleep researcher at the Karolinska Institute in Sweden, has found that stress without a disruption of sleep patterns is not enough to cause work burn-out.
While stress is clearly involved, the precise causes of the symptoms have been unclear. A high level of the stress hormone cortisol has been blamed, for instance. But based on his team’s recent work, Åkerstedt says: “We think that people can function quite well on high levels of stress - it’s only when their sleep is disrupted that you get burnout.”
The team took regular sleep EEG readings of 35 patients who had been off work for a minimum of three months. The tests consistently showed extreme sleep fragmentation and disruption. These patients were living on as little as four or five hours of sleep each night, with a 40% reduction in slow-wave sleep compared with healthy people.
One weakness of this study is that a person who doesn't have to get up and go to work every day lacks that motivation to get up in the morning and go to sleep at night. It might be that the lack of participation in work activities causing the disruption in sleep cycle.
If you are going to work heavily it can be counterproductive to let the work interfere too much with your sleep cycle. It would be interesting to know whether people who burn out and who are not sleeping regularly would benefit from melatonin supplements or some other treatment or therapy to get the sleep cycle restored to a healthy pattern.
Burn-out is not the only risk that comes from poor sleep habits while under stress. James Gangwisch and colleagues at Columbia University found that getting fewer hours of sleep per night puts one at substantial risk for obesity.
(Las Vegas, NV) - November 16, 2004 - The less you sleep, the more likely you are to become obese, according to a study being presented at the North American Association for the Study of Obesity (NAASO)'s Annual Scientific Meeting held November 14-18.
The study, by researchers at Columbia University's Mailman School of Public Health and the Obesity Research Center, demonstrated a clear link between the risk of being obese and the number of hours of sleep each night, even after controlling for depression, physical activity, alcohol consumption, ethnicity, level of education, age, and gender. The study was an analysis of data taken from the National Health and Nutrition Examination Survey I (NHANES I).
Specifically, the study found that subjects between the ages of 32 and 59 who slept four hours or less per night were 73 percent more likely to be obese than those who slept between seven and nine hours each night. People who got only five hours of sleep had a 50 percent higher risk than those who were getting a full night's rest. Those who got six hours of sleep were just 23 percent more likely to be substantially overweight.
"The results are somewhat counterintuitive, since people who sleep less are naturally burning more calories," said lead researcher James Gangwisch, a post-doctoral fellow in psychiatric epidemiology at Columbia University. "But we think it has more to do with what happens to your body when you deprive it of sleep as opposed to the amount of physical activity that you get. Other studies have shown that leptin levels decrease and grehlin levels increase in people who are sleep-deprived, leading to increased appetite and consumption."
Why would that happen? According to Gangwisch, one possible answer can be found in looking back at our early forebears. "The metabolic regulatory system may have evolved to motivate humans to store fat during summer months when the nights are shorter and food is plentiful, which was a survival mechanism for the body to prepare for the dark winter months when food would not be as plentiful," said Gangwisch. "As a result, sleeping less could serve as a trigger to the body to increase food intake and store fat."
"Sleep deprivation activates a small part of the hypothalamus (region of the brain) that is also involved in appetite regulation," says Eve Van Cauter of the University of Chicago, one of the nation's leading sleep researchers.
If the rise in obesity is caused, at least in part, by poorer sleep habits why is this the case? One explanation is that electric light allows us to more easily continue do things when it gets dark rather than go to sleep. Another possibility is that electric light causes a stimulation of cells in the eye that are involved in telling the brain whether it is day or night. Biological clocks may be getting thrown off by artificial light sources. Increased viewing of TV and computer web surfing may each be contributing to the obesity epidemic.
It might be easier to prevent undesired weight gain if we turned down the brightness levels of our TV sets and computer monitors and if we turned down internal lighting to the bare minimum. Or the use of melatonin to make one tired might help keep or take the weight off.
A number of web sites claim that it would take 40 bananas to get 1 mg of melatonin. But in my experience a few bananas can help to make one drowsy. A number of foods contain melatonin.
Pineapples, apples, oranges, bananas, strawberries, kiwi fruits, peppers, spinach, nuts and tomatoes contain melatonin. The highest melatonin concentration has been found in oats, rice and sweet corn.
Of all the plant-based foods, oats, sweet corn and rice are richest in melatonin, containing between 1,000 and 1,800 picograms (1,000,000 picograms = 1 milligram) of melatonin per gram. Ginger, tomatoes, bananas and barley have about 500 picograms per gram. However, very large amounts of food would be necessary to equal the amount of melatonin available in a supplement pill. For example, 20 bowls of oats would yield just one milligram of melatonin
One web site claims that Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) depress melatonin levels and evening exercise depresses melatonin for up to 3 hours afterward. So are people who exercise at gyms in the evening interfering with their ability to get to sleep at night? If they treat their aches and pains from a work-out by taking aspirin or ibuprofen are they increasing their likelihood of insomnia and weight gain? Could be.
Also, if you are trying to fall asleep at night it might make more sense to listen to a book-tape in the dark than to read a book using a light.
Update: There are a couple of additional reasons why getting more sleep may make weight control easier. First of all, the more hours you are awake the more hours you have to eat. Go to bed a couple of hours earlier and you might avoid one last snack before bedtime. Also, a well rested mind is more capable of judging the consequences of decisions to eat and has a stronger will to resist.
It also hurts ''executive function'' -- the ability to make clear decisions, said Dr. Philip Eichling, sleep and weight-loss specialist at Arizona. ''One of my treatments is to tell them they should move from six hours to seven hours of sleep -- less sleepy, less hungry,'' he said.
“One reason the genes for disruptive sleep may have persisted is that poor sleep patterns make people gain weight and retain fat,” said Professor Tim Spector, director of the Twin Research Unit at London’s St Thomas’ Hospital, which carried out the research.
He added: “These genes may have helped our ancestors through periods of famine and the Ice Age.”
One problem with this argument is that there are genes that can be mutated to cause people to put on more weight that would not have had the effect of disrupting sleep. Wouldn't mutations in those other genes been more heavily selected for since the sleep disrupting mutations would tend to decrease efficiency while awake? On the other hand, some people do have sleep-disrupting genetic variations. So perhaps there is something to Spector's theory.
During the study, the researchers examined the sleep patterns of 1,024 volunteers from the Wisconsin Sleep Cohort Study, a population-based longitudinal study of sleep disorders that began in 1989. Participants between the ages of 30 and 60 underwent nocturnal polysomnography (a test during which a number of physiologic variables are measured and recorded during sleep) and blood sampling once every four years. They also reported on their sleep habits every five years through questionnaires and six-day sleep diaries.
The researchers' data showed a 14.9 percent increase in ghrelin and a 15.5 percent decrease in leptin in people who consistently slept for five hours compared with those who slept for eight. Mignot said the results were consistent regardless of participants' gender, BMI or eating and exercise habits. "The effect must be very strong to appear in [this entire] population," he said.
"It was quite amazing that a hormone can track a person's self-reported amount of sleep so well," he added. "To my knowledge, this is the first time that a peripheral marker in the blood is shown to correlate with habitual sleep amounts in a general, normally behaving population."
The researchers also found that in people sleeping less than eight hours (74.4 percent of the sample), increased BMI was proportional to decreased sleep. They reported that a 3.6 percent increase in BMI corresponded to an average nightly sleep duration decrease from eight hours to five hours.
Patricia Prinz reviews the latest results in PLoS Medicine. (PDF format) Also in PDF format is the full text of the paper in PLoS Medicine.
In another study Eve Van Cauter, Esra Tasalim, Plamen Penev at the University of Chicago and colleagues found that reducing sleep in health male volunteers upped the ratio of ghrelin to leptin.
Van Cauter and colleagues studied 12 healthy male volunteers in their early 20s to see how sleep loss affected the hormones that control appetite. Theses hormones -- ghrelin and leptin, both discovered in the last ten years -- represent the 'yin-yang' of appetite regulation. Ghrelin, made by the stomach, connotes hunger. Leptin, produced by fat cells, connotes satiety, telling the brain when we have eaten enough.
Van Cauter's team measured circulating levels of leptin and ghrelin before the study, after two nights of only four hours in bed (average sleep time 3 hours and 53 minutes) and after two nights of ten hours in bed (sleep time 9 hours and 8 minutes). They used questionnaires to assess hunger and the desire for different food types.
"We were particularly interested in the ratio of the two hormones," said Van Cauter, "the balance between ghrelin and leptin."
After a night with four hours of sleep, the ration of ghrelin to leptin increased by 71 percent compared to a night with ten hours in bed.
Get lots of sleep!
|Share |||Randall Parker, 2004 November 22 01:36 AM Brain Appetite|