Study: Exposure To Morning Sunlight Helps Managing Weight 137
jones_supa (887896) writes "A new Northwestern Medicine study reports the timing, intensity and duration of your light exposure during the day is linked to your weight — the first time this has been shown. People who had most of their daily exposure to even moderately bright light in the morning had a significantly lower body mass index (BMI) than those who had most of their light exposure later in the day, the study found. It accounted for about 20 percent of a person's BMI and was independent of an individual's physical activity level, caloric intake, sleep timing, age or season. About 20 to 30 minutes of morning light is enough to affect BMI. The senior author Phyllis C. Zee rationalizes this by saying that light is the most potent agent to synchronize your internal body clock that regulates circadian rhythms, which in turn also regulate energy balance. The study was small and short. It included 54 participants (26 males, 28 females), an average age of 30. They wore a wrist actigraphy monitor that measured their light exposure and sleep parameters for seven days in normal-living conditions. Their caloric intake was determined from seven days of food logs. The study was published April 2 in the journal PLOS ONE. Giovanni Santostasi, a research fellow in neurology at Feinberg, is a co-lead author."
Vitamin D (Score:3, Interesting)
Is this caused by Vitamin D perhaps? It would be interesting to compare to people on supplements.
Here in Edmonton, Canada, my family Dr. was participating in a study where her patients were tested to Vitamin D. I ended up having to take 2000 IU a day. Not that I don't get outside; during about six months of the year you won't see any daylight from 5 pm to 9 am.
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Is this caused by Vitamin D perhaps? It would be interesting to compare to people on supplements.
Here in Edmonton, Canada, my family Dr. was participating in a study where her patients were tested to Vitamin D. I ended up having to take 2000 IU a day. Not that I don't get outside; during about six months of the year you won't see any daylight from 5 pm to 9 am.
I highly doubt it, even if it were because of Vitamin D, people on placebos, erm sorry, supplements wouldn't get the same effect.
However I think the cause it more due to the notion that if people are outside... they're moving instead of sitting down so they're burning more calories.
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There is no effect of Vitamin D, via supplement or via Direct Sunlight [soylentnews.org].
Vitamin D3 seems to decrease mortality (of all causes) by 11%.
But I agree that this present study seems to be confusing cause and effect. If you are outside early and running around in the sunshine chances are its not the light of morning that has the effect, its merely the fact that you are more active.
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Well, supposedly, the study took levels of exercise into account -- and driving to work in the morning would account for 30 minutes of sunlight exposure, without any real exercise.
Are you sure? I was under the impression that car windows filtered out a lot of UV. For example, you won't get sunburn while sitting in a car with your windows rolled up.
If it's UV that matters here, and not simply bright visible light, then being in a car wouldn't do it I suspect.
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and was independent of an individual's physical activity level, caloric intake, sleep timing, age or season. About 20 to 30 minutes of morning light is enough to affect BMI.
What it wasn't independent of: small sample size, short duration, self reported diet.
Yeah... (Score:2)
Call me cynical, but I'm just suspicious that people who get up and run around in the morning have a lower BMI because they get up and run around in the morning. The whole sunlight thing, that's just a coincidental (mis)feature of morning. By which I'm sure you can intuit my BMI range. :)
I have often remarked to my SO that the primary fault with mornings is that they don't wait until at least noon to begin.
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I have a similar opinion about breakfasts - they're generally available at the wrong end of the day.
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You've totally missed the fact that the link lead to two different studies one of which was a Meta Analysis of 180 studies, which indicated that there was no measurable effect of Vitamin D. Its not like ONE study was done and it is easily overturned by your google search.
The meta analysis more than likely included all your google search results by proxy. The study is not paywalled so go read it yourself.
This is the beauty of meta-analysis, it can find significant overlooked results of smaller studies and
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In order to wake up to sun light, a variety of factors must coincide, but chief among them is sleeping a little later instead of waking up at 5am to get ready for work and sitting in traffic for a long time just so you can sit in an office with unhealthy lighting by sunrise.
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Head outside at 9 am for a cigarette break?
It's for your health.
correlation does not prove causation (Score:5, Interesting)
Re:correlation does not prove causation (Score:4, Insightful)
In any case causation is not proven, and this is a pretty small sample anyway.
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There's no current measurement of a person's metabolic rate. I sleep later, eat more, and am older than my partner but my metabolic rate is higher due to previous lifestyle so I have a lower BMI. Anecdotal but it shows the flaw in the study. To show something like this you'd have to look at a larger but focused sample over a very long time.
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Re:correlation does not prove causation (Score:5, Insightful)
If they really wanted to find out whether sunlight affected weight, they would have done a randomized, controlled trial.
They would have randomly assigned half the people to getting exposed to sunlight early, and the other half to getting exposed to sunlight late.
Instead, they let the subjects go their merry way and simply measured their exposure to sunlight during the day.
These kind of studies give spurious results. For example, suppose the ones who are exposed to sunlight in the morning are getting up early to start their day jogging.
Re:correlation does not prove causation (Score:5, Insightful)
If they really wanted to find out whether sunlight affected weight, they would have done a randomized, controlled trial.
They would have randomly assigned half the people to getting exposed to sunlight early, and the other half to getting exposed to sunlight late.
Instead, they let the subjects go their merry way and simply measured their exposure to sunlight during the day.
These kind of studies give spurious results. For example, suppose the ones who are exposed to sunlight in the morning are getting up early to start their day jogging.
Well, no.
You don't begin a line of inquiry with a randomized, controlled trial. You begin with a study to see if there may be a correlation.
Why? If there's no correlation in a study, then there's no reason to spend the (much greater) money on a randomized trial.
If there does appear to be a correlation, you report it so that you (and others) may pursue the inquiry further.
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How else can they be self-righteous?
By having led to the ouster of Mozilla's new CEO?
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You are wrong in this case. If they just wanted to determine the correlation, they shouldn't have put the following statement in their abstract:
Exposure to moderate levels of light at biologically appropriate times can influence weight, independent of sleep timing and duration.
That's way beyond saying 'there's a correlation'
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That's a fine way of looking at things, but then the most dramatic results you should report are "It appears to be a correlation, but more study is needed." There had better be no attempt to claim a causal linkage.
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True, it's appropriate to start with a correlational study before you go on to a randomized, controlled trial.
This would have been a good study -- if they didn't come to an unjustified conclusion.
Exposure to moderate levels of light at biologically appropriate times can influence weight, independent of sleep timing and duration.
We don't know that from this study, because they couldn't control for all the other factors that might have influenced weight.
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But I think the study size is too small and the duration too short to mean anything.
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They try to correct for those factors but they can never be sure.
Maybe the biggest epidemiological study is the Nurses' Health Study, which has several thousand participants and has been going on for more than one generation. They've been recording a huge number of personal activities and medical developments. Then they run it through computers to find associations. Then they try to correct for all the factors. Then they do a randomized controlled study to find out if the association was spurious or if it r
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With 54 people I don't think I would believe them when they said they controlled for ANYTHING.
Re:correlation does not prove causation (Score:5, Funny)
Re:correlation does not prove causation (Score:4, Funny)
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I find it more likely that these people work outside during that part of the day and probably for much of their day, and since most jobs that work outdoors are more labor-intensive than most jobs indoors, that physical activity from the time one starts one's day may have more of an effect.
The only way that this can really be s
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I find it more likely that these people work outside during that part of the day ...
Perhaps. There could be any number of explanations. The important thing to note is that this is an observational study. They just collected data on people, they didn't randomly assign people to get up early. Morning people and night owls differ in many ways. Their conclusion that "morning light" is the reason seems pretty far fetched. It is far more likely that the cause is late night tv with a big bowl of potato chips.
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-1, self-righteous jackass
Could it be that people that squawk "correlation does not prove causation" without knowing what that means are just lazy and don't bother to find out what the study actually does and does not cover?
Re:correlation does not prove causation insulting (Score:3)
Maybe it is evening/night people having their natural sleep schedules disrupted in our industrialized society that contributes to a higher BMI.
AFAIK, morning sun has essentially the same spectrum as evening sun (slightly red due to the longer path through the atmosphere than at noon), and the same angle of incidence, so morning sun should have no different intrinsic effect than evening sun, if the rest of the day is spent in artificial light.
Sounds like a VERY poorly controlled experiment.
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AFAIK, morning sun has essentially the same spectrum as evening sun
No it doesn't. The authors address the differences in the spectrum in the third paragraph of the Discussion section of the study.
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I'm fat and I get up at 6:00 and am generally at work before the sun comes up. It must be because I'm lazy, and not because I commute and work stupid hours.
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I'm fat and I get up at 6:00 and am generally at work before the sun comes up. It must be because I'm lazy, and not because I commute and work stupid hours.
Well, you are too lazy to change your sig :). It's not an XP world anymore! Hell, it's even been looking a bit like a Mac world for the last few years.
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Replying from a work machine still running an XP SOE.
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...says the guy too lazy to read the summary.
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Lack of correlation is even worse (Score:3)
The other problem is lack of correlation for this hypothesis. There are large numbers of people whose work shifts that have them awakening at night to work during the night. If this study's conclusion is correct then the vast majority of these people should have a very high BMI, and the effects of working such shifts would have been noticed decades ago.
Then there are people at the high latitudes who have months of very reduced sunlight, and thus wake up in the dark for weeks on end. Again, do we see the s
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worth more research (Score:4, Insightful)
as the summary points out, it was only for 7 days with 54 people who used wrist mounted light sensors & 'food logs' but it's definitely worth a look
sunlight in the morning has all kinds of physiological benefits...IIRC recently it was linked to higher immune function
Huh huh, heh heh. (Score:2)
Does anyone else think the same as me when they see "food logs"?
Statistically Insignificant (Score:2, Informative)
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For seven days. Either dredging the data from something else or (worse) looking for the effect!. Which is claimed to be 20% of BMI. I can refute this trivially within my own household. This is arrant nonsense. For me dropping 20% of BMI means losing 40 pounds, and gee, I'll bet nobody in their study dropped 40 pounds in seven days. So precisely how could the establish the correlation? By enrolling a handful of thin early risers and fat late sleepers and watching them for seven days and concluding th
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I'll bet nobody in their study dropped 40 pounds in seven days. So precisely how could the establish the correlation?
Perhaps they were really full of shit?
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I can refute this trivially within my own household.
Haha! Good one :-D Refuting a small-sample study with an anecdote, classic!
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My pleasure:-)
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What are you basing your judgment on? Please show your work.
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Yea Right... (Score:2)
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... Look at the overweight+ people in Hawaii. And we live in the sun virtually year round!
If we can take their small sample and methodology as meaningful, and presume that you mean that Hawaiians all get up early and go right into the sun... then the point is that whatever lifestyle things make a lot of Hawaiians fat would be even worse if they all rolled out of the cot in their mom's basement and stayed there until lunchtime.
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Sample too Small (Score:2)
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Re:Benjamin Franklin (Score:5, Interesting)
Early to bed and early to rise, makes a man healthy, wealthy, and wise.
I don't know about healthy. But late to bed, late to rise, seems to make you more intelligent and wealthier [medicaldaily.com] That study looked at 1000 people, rather than 54. If both studies are accurate, it looks like you can be smart, fat, and rich, or healthy, poor and stupid.
James Thurber (Score:3)
Early to rise and early to bed makes a man healthy, wealthy, and dead.
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The early bird catches the worm. The early worm gets eaten.
Re:Benjamin Franklin (Score:5, Funny)
The early bird catches the worm. The early worm gets eaten.
The second mouse gets the cheese.
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Early to rise, early to bed, makes a man healthy, but socially dead.
Morphine (Score:2)
Early to bed and early to rise
Makes a man or woman
Miss out on the nightlife
RIP Mark Sandman.
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Early to bed and early to rise, makes a man healthy, wealthy, and wise.
The early bird catches the worm. Thus we worms nap as cats and gain their protection. Being early to rise is for the birds we're against.
depression (Score:3)
Depression is correlated with sunlight exposure. Depression is correlated with weight gain.
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Younger people are generally skinnier
Not really. Childhood obesity is an epidemic in the USA.
and sleep in.
Yep. And with all the butthurt over moving high school starting times back, we'll have some good data.
Poor Richard (Score:2)
"Early to bed and early to rise make a man healthy, wealthy and wise".
http://books.google.com/books?... [google.com]
Morning sunlight (Score:2)
Yes I do get to see the sun rise at this time of the year, as I walk home from work.
(I work Nights you insensitive clods)
54 participants? Seven days? (Score:2)
That is, "We did a tiny study for a ridiculously short amount of time without anything like controls or double blindedness and found that exposure to morning light accounts for reductions of 20% of BMI at a statistically significant level.
This could be true only if the lights one turned on when getting up "early" were frickin' laser beams attached to sharks that lopped of a major limb and ate it.
April Fool's day was Tuesday. Why post this now?
rgb
Morning sunlight? (Score:3)
Eww. I don't like that stuff! I have blackout curtains on my bedroom windows to keep it from finding me.
*Looks down at ginormo-gut*
Hmm.
NAH! I like sleeping late!
Stupid study (Score:2)
Exposed how? (Score:3)
Is exposure just a general "bathing" in sunlight? Is exposure light entering one's eyes and providing stimulation?
Does this have anything to do with the fact that I have always had a very high metabolism yet my sleep patterns rarely follow a daily/hourly routine. I do not wake/go to bed at the same time every day. I am generally awake for 18 hours, then sleep for 8, so I sort of have a 26 hour day, which, of course, causes a number of other problems, but hey, it is what it is.
26 hour day? (Score:2)
Polar Nights (Score:1)
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Sun, whole milk, dark chocolate... (Score:3)
First they tell us that dark chocolate is good for us because of the antioxidants and that it reduces the amount of fat that your body adsorbs from other foods.
http://www.scientificamerican.... [scientificamerican.com]
http://www.medicalnewstoday.co... [medicalnewstoday.com]
Then they tell us that whole milk, cheese, etc. keeps us leaner
http://www.npr.org/blogs/thesa... [npr.org]
Now bathing in sunlight (don't forget the sunscreen) will help us manage our weight.
So, I guess this means that eating dark chocolate, chasing it down with whole milk, while sitting in the sun and reading (good thing I own a Kindle) will help me get rid of those unwanted pounds... Ahhh... This IS the life.... (grin)
What exactly is morning (Score:2)
In northern countries a day in the winter is short, in southern countries it is longer. As we do not notice big difference between body weight in north and south, what is morning exactly? Is it the time just after you wake up and turn on light? Or is it time when the Sun rises? Or what?
Personal Experiance (Score:2)
A few years ago I started using a couple plug strips each with 6 'daylight' florescent bulbs during the winter (in Seattle).
Gazing into them for the 10-20 minutes of groggy 'just woke up' time gives me, personally, a boost through the whole day; followed by being able to fall asleep at a reasonable hour in the evening.
ymmv, but if you suffer from chronic sleep schedule drift, I would recommend trying it. You don't need an expensive 'lamp system' Just be sure to get the blue-ish 'daylight' bulbs, not the red
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A few years ago I started using a couple plug strips each with 6 'daylight' florescent bulbs during the winter (in Seattle).
"Daylight" florescent bulbs are just regular fluorescent bulbs with a color temperature of a bluer tone than normal. The actual light spectrum they put out isn't going to be vastly different. It's not the same as those sunlight-mimicking bulbs you're referring to.
Have you tried this same routine with normal color florescent lights by the same manufacturer to see what happens?
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Just my personal experience, in any case, I wanted to simulate natural daylight as best as possible, since studies have shown that blue light is what triggers the circadian rhythm; it's also vital to not use the lights from early evening to bedtime if you try this.
I guess I forgot to mention the cheap bulb holders (like this one http://www.hardwarestore.com/p... [hardwarestore.com] )
I also wrote a program to adjust my video cards 'color temperature' setting depending on the time of day (but it only worked on XP)
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I also wrote a program to adjust my video cards 'color temperature' setting depending on the time of day (but it only worked on XP)
Perhaps you'd like to investigate this [justgetflux.com] then.
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I spent several years working in Commercial Real Estate Management, and one thing that was always a struggle was that we'd have folks in various office type environments arguing over whether or not it was too bright or not bright enough in the office (this was in addition to everyone fighting over wh
Its the brain! (Score:1)
The reason this happens is because there is a bundle of neurons in the hypothalamus called the suprachiasmatic nucleus. These neurons receive blue light from your eyes to precisely control sleep/wake rhythms. These neurons feed directly into the arcuate nucleus, the part of the hypothalamus that senses hormones and regulates your metabolism, hunger, and alertness.
Source: Im a neuro-endocrinology researcher. Im also working on an open source genomics experiment to study this stuff. Join if you have genome an
Don't confuse causation with correlation. (Score:2)
Exception to the rule? (Score:2)
Obviously, I am once again an exception. I take the bike to work and I do it most of the week during spring, summer and fall. I have 30+ minutes of exposure to light in the morning. I'm still a fat fuck. That despite balanced meals, carbohydrate consciousness and aforementioned 3 to six hours of physical exercise per week.
So frankly, fuck all those weight 'scientists'.
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I have lost 23 kilos. I know how it works. But at the time, I've had no job. I was sleeping whenever and as long as I wanted, on most days I didn't have to be anywhere.
Then I found another job. 10kg returned in no time.
I'm telling you, what makes me fat is job induced stress and there is just no way getting around that, unless I want to get out of IT (which, in turn, would bring a lot of anxiety with it).
Redundant: This Comment! && This Study! (Score:1)
This comment is just as redundant as the request to the editors to throw garbage like this into the waste-bin instead of treading us to it and waste even more bits.
Correlation is no causation and here Northwestern Medicine ought to pay back the funding and instead be supplied with brown bags for over their heads: "This bag covers gently the red face of someone who bungled it on science"
Yep, this case could make it into a new standard textbook example why correlation is obviously no causation. It is so blood
50 people ??? (Score:2)
Well, then (Score:2)
Never mind.
There's worse science out there... (Score:3)
For all those yelling "This is clearly bad science", it's not. The summary is not the paper. The paper notes that there is a correlation between a certain pattern of light exposure and BMI in their sample group. The hard part about the paper is the models they used to capture temporal patterns of light exposure and determining if they are valid. The paper does discuss the model in detail and notes that there are issues that it fails to address.
The rest of the analysis is fairly accepted sensitivity analysis, which factors in the sample size. Also, the paper notes that there have been other studies in animals that have linked light exposure to changes in metabolism, so there is a potential for the mechanism to be causative. But the paper clearly notes in the summary that directionality of the found relationship can't be determined from this study. In other words, the paper just suggests more avenues of research into the links between light exposure, sleep rhythms and metabolism and suggests that the temporal aspects of exposure could play a role.
Finally, the intervention that it suggests is fairly harmless. If people start getting more sun in the morning, that's probably okay overall.
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For the rest your arguments, especially in the second sentence, are bollocks.