It was BIG big news just a few years back.
As recently as 2004, several study releases pointed us in the direction of looking at our sleep patterns as possible, potential indicators in weight gain, BMI, and body fat levels.
I remember it was all over the news for weeks:
“Sleep Loss May Equal Weight Gain!”
“Not Enough Sleep May Be Making You Fat!”
Many simply got the idea that if they could only catch a few more “Zzzzzz’s”, they’d find the proverbial magic bullet to weight loss.
I wanted to find out if there were new developments in the research around sleep, weight gain, and weight loss. So I searched the professional journals, and snooped around to see what new research might have been done.
And I thought I’d tell you just what I found out.
As it turns out, a recent review of the literature and findings raises more questions than it answers.
It just may be that the cause and effect may have traded places from what was previously thought!
A Forty Year Review
Granted, the recent national obesity epidemic has been “accompanied by a parallel growth in chronic sleep deprivation”.
The question persists: does sleep deprivation have an influence on appetite, physical activity, and thermoregulation that may have bearing on weight gain?
[Ref: Int. Journeal of Obesity (2008) 16 3, 643–653. doi:10.1038/oby.2007.118; “Short Sleep Duration and Weight Gain: A Systematic Review”]
Recently, 36 publications (!) spanning the years from 1966 to 2007 were reviewed for results and content with regards to “sleep duration” and obesity.
Findings in studies of children suggested short sleep duration is strongly and consistently associated with concurrent and future obesity. At the same time, results from adult cross-sectional analyses were more varied: 17 of 23 studies supporting an independent association between short sleep duration and increased weight.
It might be easy to conclude from this evidence a direct correlation between less sleep and weight gain.
Not so fast.
Chicken Or Egg?
As always with research, it is best to play devil’s advocate when getting to the truth. What may seem obvious can actually just be an interesting confluence of events.
At the same time, it can give us valuable information with which to investigate our personal health.
Consider, for example, these possible explanations of the “less sleep/more weight” correlation.
All 3 of these scenarios, and more, are presented by the study team referred above as possible reasons for positive correlation between weight and sleep.
1) Maybe the overweight individuals in the studies report less sleep because of sleep disturbance that can accompany increased fat weight, such as sleep apnea.
In other words, the weight itself disturbs the sleep, the disturbed sleep may not cause the weight gain.
2) Maybe the overweight individuals in the studies are unable to get better sleep because of medical disorders such as chronic pain or psychiatric disorders such as depression, which may in turn limit an individual’s ability to be physically active.
This situation would quite likely interfere with sleep continuity.
3) Perhaps overweight individuals are eating more during the night when disturbed sleeping patterns result in forays to fridge and pantry.
Night restless ness and roaming? Bored? Eating?
And then there’s this very interesting thought:
Socioeconomic status (SES) may also confound the sleep–weight relationship. People of lower SES may have less favorable sleep environments, work longer hours, and work less desirable hours such as rotating or overnight shifts, resulting in poor sleep. Low income has been associated with reduced sleep durations.
At the same time, several studies in this review have adjusted for SES status in their analysis and have found that the sleep–weight association persisted.
Hold It: Don’t Throw The Baby Out!
This study concluded: more research! Cause and effect are not as clear as we like them to be much of the time, when it comes to research.
But let’s remember that There are many, MANY reasons to cultivate a good sleeping practice.
Several studies referred to health indicators improved with 7-8 hours of sleep/day, and reduced in general at 5-7/hours a day.
This would include hormonal profiles that need to be considered for overall health, including but not limited to:
1) levels of human growth hormone (HGH), which is released during sleep cycles and has a powerful impact on other health measures
2) cortisol, another hormone intricately connected with sleep and stress levels
Of course, when we’re looking at weight management, weight loss, and holistic health, it can be tough to isolate the variables for an exact prescription of behaviors.
Enough sleep will not necessarily be the “magic bullet” to shaking off that excess weight, though it may play an indirect role by allowing for better overall function, reduced stress, more energy and vitality for staying active and for making better dietary choices – and together THOSE elements play a significant role in weight and health.
According to my findings, the consistencies for overall patterns of health and optimal hormonal profile?
1) When it comes to sleep, aspire to 7 – 8 hours each day.
2) This can be enhanced by regular physical activity, good nutrition, and solid stress management.
But you knew that, didn’t you? And I bet you’re like me in that I find it’s always good to get these simple, straightforward reminders!
And from the experiences of my clients, I’m finding that the stress management plays a big role in the weight loss equation; bigger than we may previously have suspected.
Can’t say without a shadow of doubt that more sleep means less weight, but just maybe the stress factor is a closely related chunk on this ball of wax. The sleep connection just may be an influence; evidently the jury is still out on that one. I’ll keep digging around in my usual way and let you know what other nuggets I uncover!
Questions? I invite you to post them in “comments” on this post.
© 2009 Lani Muelrath All Rights Reserved
I think it’s very interesting that this review spanned 40 years of articles! It will be interesting to see what develops as time goes on.
I am very intersted to know more about the hgh levels and how to improve that. Will you be writing about that too?
Thanks for a great article!
I was impressed by the breadth of the review of the literature as well.
You betcha I’ve got something cookin’ with hgh. Stay tuned.
And thank you for writing! I’m glad you found value in this post and stopped to tell me about it.