Weighing effects of too little sleep | Chicago Tribune
Weighing effects of too little sleep
Link between shut-eye and obesity studied
By Judy Peres
Tribune staff reporter
Published July 25, 2006
The phrase "sleep it off" could take on a whole new meaning if Esra Tasali is right.
The University of Chicago researcher is part of a nationwide cadre of scientists who are uncovering evidence that too little sleep could lead to weight gain. If their current studies confirm the link, the next step will be to find out whether sleeping more can help people slim down.
Scientists already know that people who sleep less are fatter.
In an attempt to figure out how sleep and body weight are related, the U. of C. team measured levels of two hormones that control appetite, leptin and ghrelin, in 12 healthy young men. Half the subjects were allowed to sleep only four hours a night, while the others were given 10 hours of shut-eye. The researchers found that sleep deprivation had a significant effect on the two hormones.
"The men who slept only four hours not only were subjectively hungrier," Tasali said, "but we also had objective evidence that hormones were telling their brains they needed more energy."
But all this doesn't yet prove that sleep deprivation actually causes people to gain weight.
"Nobody has shown a cause-effect relation between restricted sleep and obesity," cautioned Dr. Robert Vorona of Eastern Virginia Medical School.
Tasali agreed: "We still need to identify the underlying mechanism [for] what makes people fatter when they're sleep-deprived."
One clue is that her sleep-deprived subjects craved high-carbohydrate foods -- candy, cookies and ice cream -- far more than, say, vegetables or yogurt.
"Maybe that's because the brain uses glucose -- sugar -- as it's main energy source," Tasali said.
Recent surveys have found that about two-thirds of Americans are overweight or obese, and an estimated 63 percent don't get the recommended eight hours of sleep per night.
The Sleep Disorders Center at Northwestern Memorial Hospital is investigating whether improving sleep in older people with insomnia can improve their health. "That's really where the future is," said Dr. Phyllis Zee, director of the center.
Another planned study will enroll people who are overweight and see if getting them to sleep better makes it easier for them to lose weight.
"Potentially, sleep will be a modifiable risk for obesity," Zee said.
Even though the data are not yet in, Zee said she tells her patients they need at least seven hours of sleep a night, on average, to stay healthy.
Lack of sleep has been associated with cognitive problems, diabetes and high blood pressure, in addition to obesity.
As evidence mounts that sleep is important for health, another body of research suggests that people are getting a lot less sleep than they need.
A study published in this month's American Journal of Epidemiology found that middle-age men and women sleep much less than they should and even less than they think they do.
The study, carried out jointly with researchers from Northwestern, also found that blacks sleep less than whites, men sleep less than women, and the poor sleep less than the wealthy.
The study combined sleep diaries with wrist actigraphy, which uses a motion sensor to measure when people go to bed and when they fall asleep. The researchers found people spent an average of 7.5 hours in bed but only 6.1 hours sleeping. The average for black men was only 5.1 hours.
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I have to get some f'ing sleep
Link between shut-eye and obesity studied
By Judy Peres
Tribune staff reporter
Published July 25, 2006
The phrase "sleep it off" could take on a whole new meaning if Esra Tasali is right.
The University of Chicago researcher is part of a nationwide cadre of scientists who are uncovering evidence that too little sleep could lead to weight gain. If their current studies confirm the link, the next step will be to find out whether sleeping more can help people slim down.
Scientists already know that people who sleep less are fatter.
In an attempt to figure out how sleep and body weight are related, the U. of C. team measured levels of two hormones that control appetite, leptin and ghrelin, in 12 healthy young men. Half the subjects were allowed to sleep only four hours a night, while the others were given 10 hours of shut-eye. The researchers found that sleep deprivation had a significant effect on the two hormones.
"The men who slept only four hours not only were subjectively hungrier," Tasali said, "but we also had objective evidence that hormones were telling their brains they needed more energy."
But all this doesn't yet prove that sleep deprivation actually causes people to gain weight.
"Nobody has shown a cause-effect relation between restricted sleep and obesity," cautioned Dr. Robert Vorona of Eastern Virginia Medical School.
Tasali agreed: "We still need to identify the underlying mechanism [for] what makes people fatter when they're sleep-deprived."
One clue is that her sleep-deprived subjects craved high-carbohydrate foods -- candy, cookies and ice cream -- far more than, say, vegetables or yogurt.
"Maybe that's because the brain uses glucose -- sugar -- as it's main energy source," Tasali said.
Recent surveys have found that about two-thirds of Americans are overweight or obese, and an estimated 63 percent don't get the recommended eight hours of sleep per night.
The Sleep Disorders Center at Northwestern Memorial Hospital is investigating whether improving sleep in older people with insomnia can improve their health. "That's really where the future is," said Dr. Phyllis Zee, director of the center.
Another planned study will enroll people who are overweight and see if getting them to sleep better makes it easier for them to lose weight.
"Potentially, sleep will be a modifiable risk for obesity," Zee said.
Even though the data are not yet in, Zee said she tells her patients they need at least seven hours of sleep a night, on average, to stay healthy.
Lack of sleep has been associated with cognitive problems, diabetes and high blood pressure, in addition to obesity.
As evidence mounts that sleep is important for health, another body of research suggests that people are getting a lot less sleep than they need.
A study published in this month's American Journal of Epidemiology found that middle-age men and women sleep much less than they should and even less than they think they do.
The study, carried out jointly with researchers from Northwestern, also found that blacks sleep less than whites, men sleep less than women, and the poor sleep less than the wealthy.
The study combined sleep diaries with wrist actigraphy, which uses a motion sensor to measure when people go to bed and when they fall asleep. The researchers found people spent an average of 7.5 hours in bed but only 6.1 hours sleeping. The average for black men was only 5.1 hours.
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I have to get some f'ing sleep
posted by Beto at
2:02 PM
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