Rotating Night Shift Work and Type 2 Diabetes in Women

A new study found that the longer women worked rotating night shifts, the greater their risk of developing type 2 diabetes. Researchers also found that extended years of rotating night shift work was associated with weight gain. The weight gain may have contributed to the increased risk of type 2 diabetes.

Women who worked rotating night shifts for three to nine years faced a 20 percent increased risk of type 2 diabetes. Women who worked nights for 10 to 19 years had a 40 percent rise in risk. And women who worked night shifts for over 20 years were 58 percent more at risk. Women who worked rotating night shifts also gained more weight and were more likely to become obese during the follow-up.

Rotating night shift work was defined as three or more night shifts plus day and evening hours each month. The Harvard School of Public Health tracked more than 175,000 U.S. nurses for this study. Findings were published Dec. 6 in the journal PLoS Medicine.

Researchers said the findings need to be confirmed in men and ethnic groups (96 percent of the nurses were white Caucasians). The U.S. Centers for Disease Control and Prevention (CDC) estimates that 15 million Americans work full time on evening shifts, night shifts, rotating shifts or other irregular schedules.

Read more about shift work sleep disorder and women’s sleep needs. More stories about sleep and type 2 diabetes are available on the Sleep Education Blog.

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Sleep More, Stress Less to Achieve Your Weight Loss Goals

Weight Watchers and Jenny Craig should get with the program. Neither of the weight loss leaders integrates sleep education and sleep diaries. And the companies are making a big mistake, new research suggests. Popular approaches used by groups like Weight Watchers use a diary to keep track of food and exercise. Adding an extra column in the diary for hours slept would be a minor change that could make a significant impact.

A new study in the International Journal of Obesity found that adequate sleep increases your chances of success during weight loss efforts. People trying to lose at least 10 pounds more often reached their goal if they had six to eight hours of sleep per night. Stress reduction also helps with weight loss, the study reports.

A group of 500 study participants were instructed to lose 10 pounds over a six month period. All participants attended weekly weigh-in and educational meetings. Instructors at the meetings encouraged the participants to consume 500 fewer calories per day, adopt a healthy low-fat, low-sugar diet and exercise for at least 180 minutes a week. Participants were required to keep record of how long they slept, stress levels and mood. The class instructors encouraged participants to keep a food diary as well.

Nearly three-quarters of the people who slept more than six hours and kept a low-stress lifestyle were successful in losing 10 pounds or more and were twice as likely to meet their goals compared to those who get six or fewer hours of sleep.

Sleep loss tends to lead to weight gain or undermine dietary weight loss because it changes the body’s hormone levels. Lower leptin and higher ghrelin can lead to a slower metabolism but a bigger appetite for junk food.

Whether you are trying to lose weight or stay trim for swimsuit season, prioritizing sleep is always a good idea. The American Academy of Sleep Medicine recommends adults get at least seven hours of sleep. Don’t underestimate the power of diet and exercise. Weight loss programs like Weight Watchers work for many people because they educate people to make the right choices and encourage them to hold themselves accountable for their health.

Middle-aged Sleep Loss Linked to Weight Gain for Women

It’s a troubling scenario for women as they get older: lose sleep and gain weight. New findings suggest middle-aged women with insomnia will likely pack on pounds.

A Finnish study published in the International Journal of Obesity followed more than 7,300 middle-aged men and women for seven years. About a third of the women who reported having difficulty sleeping posted a double-digit weight gain.

Sleep problems, whether chronic or occasional, came before weight gain in many cases. Lead investigator Peppi Lyytikainen told Reuters Health the findings do not prove a causal relationship. He believes the findings may suggest improving sleep quality can help with losing weight. It’s still unknown if treating insomnia will cause weight loss.

Men may not have to worry. Results showed no link between insomnia and weight gain in males. However, previous research suggests otherwise. Men who sleep less may gain weight because they exercise less and eat fewer healthy foods. Short sleep may alter appetite-regulating hormones and cause you to crave high-calorie, high-carb foods.

Middle-aged women are susceptible to sleep distubances due to the hormonal and physical changes related to menopause. Its not unusual for post-menopausal women to report poor sleep quality or insomnia.

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Obese kids more at risk for snoring, obstructive sleep apnea, says Italian study

Childhood obesity carries a lot of risks, especially later in life, and new research shows it can affect sleep early on.

A new study suggests kids who are significantly overweight are twice as likely to have obstructive sleep apnea. Those who don’t are even more prone to snore loudly. The results were published in the May issue of the journal Chest.

Italian researchers compared more than 800 elementary school- or preschool-aged children in Southern Italy. The study divided them into three groups based on their answers to a questionnaire about snoring.

Scientists classified 5.4 percent of the children as habitual snorers. 17 percent occasionally snored. A vast majority – 77.5 percent – did not snore at all.

The habitual snorers received screenings for obstructive sleep apnea. Only 14 children had the sleep disorder.

The researchers calculated each child’s body mass index (BMI) based on Italian growth charts. About 8 percent of the children were obese. 15 percent were overweight.

Through statistical analysis, it turned out 12.5 percent of obese children snored regularly. Only 4.6 percent of normal-weight children were considered habitual snorers.

3.1 percent of obese children included in the study had obstructive sleep apnea. That’s twice many as their peers.

These findings are counter to previous research published in the Journal of Clinical Sleep Medicine and reported in the Sleepeducation blog. An Australian study concluded obesity increased the risk for obstructive sleep apnea for teens but not younger children.

Obstructive sleep apnea is a serious disorder and the symptoms can be mistaken for common snoring. Children with OSA often appear to struggler to breath during sleep, with obvious pauses and gasps for breath.

Two percent of healthy young children have OSA, according to the American Academy of Sleep Medicine.

Learn more about obstructive sleep apnea in children or snoring. Get help at an AASM-accredited sleep center near you.

Image courtesy Angela Wylie, Melbourne Sunday Age

Study: Sleep-starved nights may fuel binge eating

A study published in the American Journal of Clinical Nutrition found healthy young men tended to take in an extra Big Mac worth of calories after a sleep-deprived night.

It’s the latest study to link sleep to unhealthy eating patterns and obesity.

Researchers in France allowed a dozen study participants to eat whatever they wanted over two sleep-regulated 48-hour periods.

The first session, the group of men went to bed at midnight and woke up at 8 a.m. both days. The next time around, they were limited to only four hours of sleep on the second day.

On average, the participants consumed 22 percent more calories when they did not get a full night of sleep. The extra eating happened during breakfast and dinner.

The scientists who carried out the study told Reuters Health the findings make it clear that getting an adequate amount of sleep is essential for energy conservation and not just the recovery process.

There are various ways skimping on sleep is linked to bulging bellies. Another study found people tend to exercise less and are less active overall when they don’t sleep.

Short sleep may also cause you to hunger for high-calorie, high-carb foods.

Learn more about sleep and weight gain.

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Sleep Loss & Weight Gain: Genetic or Behavioral?

There is growing evidence linking chronic sleep loss with an increased risk of obesity. Short sleep durations are associated with higher body mass index (BMI) scores.

What is the nature of this relationship? Is it genetic? Environmental? Behavioral?

A new study provides some intriguing insight. The results were published last month in the Journal of Clinical Sleep Medicine.

The study surveyed 612 pairs of twins. Each pair was raised together in the same household.

They had an average age of about 37 years. They reported their height, weight and habitual sleep duration.

Results show that 25 percent of participants reported sleeping less than seven hours per night. These short sleepers had a higher average BMI (26.0) than those with a typical sleep duration of seven to 8.9 hours per night (24.8).

An adult with a BMI of 18.5 to 24.9 is considered to be at a “normal” weight. An adult who has a BMI of 25 to 29.9 is considered to be “overweight.”

The results were confirmed in an analysis of 423 monozygotic pairs. Each of these twin pairs shares 100 percent of their genetics. Short sleepers again had a higher BMI (25.7) than normal sleepers (24.7).

There also were 245 twin pairs that differed in their sleep durations. An analysis of these pairs also produced similar results. The shorter-sleeping twins had a higher BMI (25.8) than the twins who had a typical sleep duration (24.9).

How strong was the genetic influence on sleep duration? Further analysis produced a modest heritability estimate of 31 percent for sleep duration. In comparison, the heritability estimate for BMI was 76 percent.

There was little evidence of shared genetics between sleep duration and BMI. Common environmental factors also appeared to have little influence on the link between sleep and BMI.

The results support the idea that voluntary sleep restriction affects BMI. This effect appears to be independent of familial factors.

Do you know your BMI? Use the BMI Calculator on the left side of the blog to find out.

Read more about sleep and obesity and sleep and weight gain.

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Sleep, Weight & Abdominal Fat

A new study examined the relationship between sleep duration and abdominal fat in a group of Hispanic and African-American young adults. The results were published today in the journal Sleep.

The study involved 1,107 adults between 18 and 81 years of age. Data were collected from 332 African-Americans and 775 Hispanics. Sixty-two percent of participants were female.

Body mass index (BMI) and abdominal fat were measured at a five-year interval. Belly fat was measured using abdominal computed tomography (CT) scans.

Results show that the mean self-reported nightly sleep duration was 6.7 hours at baseline. Seventeen percent of the sample reported sleeping five hours or less per night.

There was no link between sleep duration and abdominal fat change in people older than 40 years of age. But short and long sleep durations were associated with increases in BMI and belly fat in people younger than 40 years of age. The association was strongest in people who reported sleeping five hours or less per night.

They had an average BMI increase over five years that was 1.8 kg/m2 higher than people who slept six to seven hours each night. They also gained more abdominal fat.

“Appropriate amounts of sleep are important for maintenance of healthy weight,” lead author Dr. Kristen Hairston told the AASM. “In a group of African-American and Hispanic participants, those who slept less than this had greater increases in belly fat over a five-year period.”

The CDC reports that blacks are 51 percent more likely to be obese than whites. Hispanics are 21 percent more likely to be obese than whites.

The authors proposed that short sleep may promote abdominal fat gain by increasing hunger and caloric intake. It also may increase fatigue and reduce energy expenditure. Both increased caloric intake and decreased vigorous activity were observed in the short sleep group.

The authors also suggested that doctors should educate young adults about the important role of sleep in a healthy lifestyle. This is most important when young adults transition to life stages that often involve sleep deprivation. These include entering college, getting married and having children.

Last year a study found that blacks had a 78 percent increased risk of obesity related to short sleep. The risk of obesity related to short sleep in whites was increased by 43 percent.

Read more about sleep and weight gain and sleep and race.

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Sleep, Weight Gain & Obesity

A large Japanese study examined the relationship between sleep duration, weight gain and obesity. The results were published this month in the journal Sleep.

The study involved 35,247 employees of an electric power company in Japan. They were evaluated at an annual health checkup in 2006 and 2007. Usual sleep duration was self-reported.

Typically obesity in adults is defined as having a body mass index (BMI) of 30 or higher. But in this study a BMI of 25 or higher was considered to be obese. This criterion has been proposed for Asia-Pacific populations.

Results show that about 36 percent of men and 12.5 percent of women were obese. About six percent of the non-obese men were obese at the one-year follow-up.

Short sleep duration was associated with both weight gain and the development of obesity in men. The men who reported sleeping less than five hours per night were 91 percent more likely to develop obesity than men who slept seven to less than eight hours. Men who slept five to less than six hours per night were 50 percent more likely to become obese.

“I believe the data are currently compelling enough to recommend good diet, adequate exercise, AND adequate sleep in people trying to lose weight,” wrote Dr. Najib Ayas in a commentary on the study.

Sleep and weight are interconnected in a variety of ways. A recent study suggested that short sleep may lead to weight gain by reducing exercise. And eating when you should be sleeping may lead to weight gain.

Adequate sleep may be associated with more healthful food choices. But short sleep may cause you to crave more high-calorie, high-carb foods. And it may affect the levels of the appetite-regulating hormones leptin and ghrelin.

Read more about sleep and weight gain and sleep and obesity.

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Sleep, Exercise & Weight Gain

According to Reuters News, the results of a small study make a common-sense claim: Lack of sleep leads to lack of exercise, which leads to weight gain.

Several studies have found that people who are not sleeping enough tend to gain weight. But a connection was never explained fully.

Last year, the Sleep Education Blog reported that sleep deprivation causes changes in hormones that regulate your appetite. This could eventually lead to weight gain.

The results of this study may point to a simpler explanation.

The study took place in Germany. It involved 15 healthy men who were of normal weight. Participants were observed for four nights in a sleep lab. On two of the nights, the men slept for eight hours. For the other two, they were only allowed to sleep for four hours. During the following days, the men wore wrist devices to track their movement.

On the days following sleep deprivation, the participants’ activity levels fell. After getting eight hours of sleep, the men spent 25 percent of their time awake doing high-intensity exercise. After four hours of sleep, the amount of time spent doing these activities fell to 22 percent.

The men did not report feeling more hungry, and they did not eat more after the nights of sleep deprivation. No changes in blood levels or appetite-regulating hormones were found.

The authors of the study note that their findings do not eliminate a potential link between hunger, appetite-regulating hormones and chronic sleep deprivation. But they do indicate that even a small amount of sleep loss can reduce physical activity. Over time, if you don’t exercise you might begin to put on weight.

Visit Sleep Education.com to learn more about the link between sleep and weight.

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Sleep & Weight Gain: Watch When You Eat

A new study of mice provides the first causal evidence that links meal timing and increased weight gain, reports Northwestern University. The study suggests that eating when you should be sleeping may lead to weight gain.

It might seem easy to eliminate a late-night snack; but meal timing can be a problem for shift workers.

"One of our research interests is shift workers, who tend to be overweight," said lead author Deanna M. Arble. "Their schedules force them to eat at times that conflict with their natural body rhythms.”

The researchers fed mice a high-fat diet over a period of six weeks. Some ate during naturally wakeful hours; others ate when they normally would be asleep.

Mice that ate during normal sleeping hours had a 48-percent weight gain; mice that ate the same type and amount of food during naturally wakeful hours had only a 20-percent weight gain.

A 2008 review by Northwestern researchers explored the links between sleep and energy metabolism. The review suggests that sleep loss and obesity may be "interacting epidemics." It also indicates that the circadian clock system plays a fundamental role in energy metabolism.

Earlier this year the Sleep Education Blog reported that a “sleep diet” may be one way to lose weight. Learn more about the links between sleep and weight on SleepEducation.com.

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Race, Sleep & Obesity

A study that was presented this week at SLEEP 2009 in Seattle, Wash., examined the link between race, sleep and obesity.

The study involved 29,818 U.S. adults. The data came from the 2005 National Health Interview Survey. Information was collected during face-to-face interviews.

Results show that 52 percent of blacks and 38 percent of whites were obese. Only 23 percent of blacks and 30 percent of whites reported sleeping seven hours per night. Blacks also were more likely than whites to have a “short sleep” duration of five hours or less per night.

So was there a connection between race, sleep and obesity?

Statistical analysis showed that blacks had a 78 percent increased risk of obesity related to short sleep; the risk of obesity related to short sleep in whites was increased by 43 percent.

“Both black and white Americans who were obese tended to have short sleep duration,” study author Girardin Jean-Louis, PhD, told the AASM.

Learn more about sleep and weight on SleepEducation.com.

Insomnia and Weight Gain

A new study examined the link between insomnia and weight gain.

The study involved 14 men with primary insomnia and 24 healthy controls. It measured their levels of the “hunger hormones” leptin and ghrelin three times during one night of sleep.

Results show that men with insomnia had less total sleep time than controls. Leptin levels were similar between the two groups. Leptin helps to suppress your appetite and increase your metabolism.

But ghrelin levels were about 30 percent lower in men with insomnia. Ghrelin stimulates appetite.

So it would seem that insomnia lowers your risk of weight gain. Less ghrelin means you would be less hungry.

But this may not be the case. Lead author Sarosh Motivala of UCLA thinks that a change may occur during the day to increase appetite. Other studies show that sleep loss decreases leptin and increases ghrelin.

What is clear is that insomnia disrupts how the body regulates appetite.

"The current study shows that insomnia patients have a dysregulation in energy balance that could explain why these patients gain weight over time," Motivala said in a UCLA statement. “"This is an exciting finding because it highlights how diverse behaviors like sleep and eating are connected.”

Most people with insomnia have “secondary” insomnia. It occurs along with another medical problem, mental illness or sleep disorder. It also may result from the use of a medication or substance.

The men in this study had “primary insomnia.” This kind of insomnia is unrelated to another health problem. It is estimated that about 25 percent of people with insomnia have primary insomnia.

A 2008 study in the journal Sleep linked primary insomnia to low levels of a brain chemical. Results show that GABA levels are reduced by 30 percent in adults with chronic primary insomnia.

Learn more about the link between sleep and weight.