Consistent Bedtime Linked to Lower Body Fat (and Sanity)


A volume of studies in the last decade has indicated that sleep deprivation can lead to weight gain. Maybe all the running around you do in your dreams actually burns calories. I like that theory. Now new research by Brigham Young University indicates not only does the amount of sleep matter to weight maintenance, but also the consistency of your bedtime and wake time. These two factors of sleep maintenance influence body fat.

Exercise science professor Bruce Bailey studied more than 300 women from two major Western U.S. universities over the course of several weeks and found that those with the best sleeping habits had healthier weights.

The main findings from the study, published online in the American Journal of Health Promotion:

• A consistent bed time and, especially, a consistent wake time are related to lower body fat.
• Getting less than 6.5 or more than 8.5 hours of sleep per night is associated with higher body fat.
• Quality of sleep is important for body composition.

Women in the study were first assessed for body composition, and then were given an activity tracker to record their movements during the day and their sleep patterns at night. Researchers tracked sleep patterns of the participants (ages 17-26) for one week.

The most surprising finding from the study, according to the researchers, was the link between bed time and wake time consistency and body weight. Study participants who went to bed and woke up at, or around the same time each day had lower body fat. Those with more than 90 minutes of variation in sleep and wake time during the week had higher body fat than those with less than 60 minutes of variation.

Wake time was particularly linked to body fat: Those who woke up at the same time each morning had lower body fat. Staying up late and even sleeping in may be doing more harm than good, Bailey said.

“We have these internal clocks and throwing them off and not allowing them to get into a pattern does have an impact on our physiology,” Bailey said.

Bailey related consistent sleep patterns to having good sleep hygiene. When sleep hygiene is altered, it can influence physical activity patterns, and affect some of the hormones related to food consumption contributing to excess body fat.

The study is consistent with research on how sleep patterns can affect depression and other mood disorders. Practicing good sleep hygiene—going to bed at the same time each night and waking at the same time each morning—is crucial to maintaining good mental health.

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Published originally on Sanity Break at Everyday Health.

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Therese Borchard
I am a writer and chaplain trying to live a simple life in Annapolis, Maryland.

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3 Responses
  1. I hear you and I would very much like to have consistency in this area, but what’s a bi-polar person to do?

    I usually get up at the same time each day, and I don’t take naps (hardly ever), but in an average week, I’ll have one or two nights where I get around two hours of sleep. I feel LUCKY if I get seven hours in a given night.

    My doctor won’t prescribe sleep meds for me. I’ve asked.

  2. Popsie

    Good to know and a good motivator to stick to good sleep hygiene. I recently changed my diet based on book “grain brain” and it’s been about 3weeks of this change and now I am noticing that I am waking earlier more naturally, where before I was tending to sleep in, and this past weekend, I didn’t need my naps, as I usually do. I am feeling less lethargic in general. I’ve also lost about 5lbs – yippee! I just hope I can stick to this new healthy lifestyle of eating, and not regress to my old habits. Going back to the book and re-reading helps to re-inspire and motivate me. It’s all connected really, what we feed ourselves, exercise, de-stressing/refuge from daily life, all interact to help keep us healthy physically and mentally, easier said than done at times, and I know the mental illness monster can still rear it’s ugly head despite all our good efforts, just like a physical illness like cancer can strike a perfectly healthy individual. They say god doesn’t give us anything more
    Than we can bear, he/she must think some of us are incredibly strong, I’m not sure if I buy this explanation but sometimes when things get really bad it can give me comfort.