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Can Lowering Your Thermostat Raise Your Metabolism?

By: , SparkPeople Blogger
3/7/2012 10:00 AM   :  41 comments   :  18,226 Views

See More: cathy cram, wellness,
You may want to think twice about turning up your thermostat when the temperatures dip. Compelling research is focusing on the effect of cold on the human body, and how a type of fat called ''brown fat'' may affect heat production.
 
The human body has two types of fat: the kind we all know and dislike, ''white fat'' and another much more metabolically active fat termed ''brown fat.'' The white adipose tissue (WAT) functions to store excess energy, whereas the brown adipose tissue (BAT) has a much different function of burning WAT stores to produce heat.

The recent research into BAT has changed the past view that brown fat was only present in infants (who aren't able to shiver well) as a mechanism to generate heat.  It was thought that, as we reached adulthood, we lost those brown fat stores.
 
One of the reasons it was thought that humans lost their BAT stores after infancy is because the stores are quite tiny (just several ounces) and are found in hard-to-detect areas such as the sides of the neck, collarbone, scapula and along the spine. Interestingly, brown fat really is brown because it is rich in iron.
 
Advances in medical technology have made it possible for researchers to detect these small pockets of BAT in adult humans using scans, and they are able to see the areas of BAT ''light up'' when study subjects are put into cold rooms without insulating clothing.One current study found that when people are exposed to cold, the BAT activates and draws fuel from the WAT to heat the body.     
 
A recently published paper in the Journal of Clinical Investigation helped to define what type of fuel was burned by BAT. It was supposed that brown fat cells used glucose as a fuel, but this study showed that the major source of fuel for BAT is white fat stores. Once the BAT cells run out of the limited stores of glucose, they switch over to fat. The study showed that when the subjects were put into a cold environment that caused them to feel chilled (but not shivering) they had an 80% increase in metabolic rate, greatly increasing their heat production.
 
Another compelling area of research is exploring how exercise may cause WAT to be converted to BAT. Researchers found that in mice, the influence of a hormone causes white fat to become the metabolically active brown fat when mice were exercised.  It's an intriguing question whether this conversion could be observed in humans with exercise, and hopefully research will continue in this area.
 
An interesting finding in the studies on BAT is that obese individuals show little to no BAT activity when exposed to cold. There's no clear answer regarding the lack of BAT activity in the obese subjects, and it's caused speculation over whether the lack of BAT may contribute to obesity in some individuals.
 
Without becoming part of a study, how can you estimate your level of BAT? I've listed below several points that research in BAT has helped define.
 
-BAT is inversely related to body fat, so obese individuals have a lower level of BAT than those that are lean.
 
-Men have lower amounts of BAT than women.
 
-The older the individual, the lower the amount of BAT.
 
-There's a correlation between fasting high blood sugar levels and reduced BAT.
 
It's not clear how these markers directly affect BAT in the body, or whether age alone results in reduced BAT levels. Factors such as age-related weight gain or reduced activity levels may be contributing factors that caused the studies to find age related declines. These are all interesting questions, and future research may offer more answers, and discover innovative methods of stimulating BAT activity and conversion of white fat to brown to help treat obesity.
 
The current research does offer some tips that may help you stimulate your body's BAT activity.
 
-Turn down your thermostat in winter. One study showed that there were significant increases in BAT in nearly 1/2 the subjects who were kept in a 66-degree or lower room. If the temperature was increased to 80 degrees no BAT activity was detected.
 
-Stay active and include exercise in your daily routine.
 
-Avoid smoking. Research in this field found that non-smokers had higher BAT activity than smokers.
 
-Get some fresh air. One study showed that people that worked outdoors had higher BAT activity than those who were indoors most of the day.
 
-You are what you eat, especially where BAT is concerned. People who had the highest amount of BAT activity in studies also had lower levels of fasting blood glucose and body mass indexes. Avoid simple carbs and excess calories to keep weight within healthy levels.
 
I've gradually been dialing down my winter home temperature to between 60 degrees at night and 65 during the day.  I tend to run warm normally so it's out of comfort that I keep my home cooler, but I do think that over time I've adapted by kicking up my metabolism when the temperature drops.  Now I'm quite uncomfortable in homes where the temperature is kept at 68 degrees or higher, and feel most comfortable in the winter months.  After reading all the research on BAT and cold, I'm glad that I've been keeping my home cooler all along and wonder if that may be why I always seem to drop a few pounds during the winter months.
 
The bottom line? There's no downside to incorporating some of the BAT activations tips listed above.  Best of all, turning your thermostat down a few degrees this winter has a two-fold effect; it may be better for your metabolism, and it's certainly better for the environment!
 


Do you tend to keep your thermostat high or low in the winter?



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Comments

  • MARTY32M
    41
    I exercise naked in a cold basement. Would that help explain why I'm not overweight? - 2/17/2013   10:33:19 AM
  • SEPTLEFTY
    40
    very interesting - 3/23/2012   10:02:29 PM
  • PHYSICSGUY
    39
    I studied BAT 40 years ago as a physiology post grad. I am glad it has been found by active scans in adults and it would be wonderful if it can be activated. I am skeptical that one tissue type converts to another. I understand (may not be up to date) that we all have the same number of fat cells as we had as an infant, but they can each expand 50 fold. My theory at the time was that some infants are bundled warmly and kept in warm rooms and others werent. Those kept warm lost their BAT and would be prone to obesity later in life; the cooler ones retained it. Since I didnt have infants to experiment with, my theory is only conjecture. Someone may be interested in interviewing mothers of obese and normal adults concerning the nursery temperature for the first few months and look for a correlation. - 3/12/2012   11:16:21 PM
  • 38
    I heard this was the case but didn't believe it. Maybe I should turn the thermostat down. - 3/10/2012   11:26:58 PM
  • 37
    Interesting article. Thanks! - 3/9/2012   1:53:41 PM
  • 36
    I knew about white and brown rice! White fat? Brown fat? Never heard this before, but I do learn something new on this site everyday! - 3/9/2012   8:48:59 AM
  • BLUESPARKLES
    35
    I'm cold sometimes even in the 70s outside, the absolute lowest I can set my thermostat in the winter is 70, and that is with several layers of clothes, socks and lined slippers, a blanket, and an also freezing dog snuggling. At night it stays 70 with flannel sheets, fleece pj's, two heavy warm blankets, same dog, and always warm husband. If I even drop the setting to 69 I am in such pain I can't stand it. Sometimes hubby ups it to 72 because he hates to see me so miserably cold.

    At least I save a lot of money in the summer....only turn AC on if it's upper 80s outside or extremely high humidity, and even when it's on it's set to 80.
    - 3/8/2012   8:04:36 PM
  • 34
    So THAT explains it!!! - 3/8/2012   3:07:56 PM
  • 33
    Fascinating... never heard of this before! Thanks for sharing! - 3/8/2012   1:18:01 PM
  • 32
    I keep trying to keep my thermostat down in the winter to save money, but it is always freezing in the house, so it is back up to 68 and 72 if I am taking a bath. Then I still have to have space heaters on in the room I'm in. It is freezing in the house from about late September until at least the first of June, then it runs around 90 in here (I don't have A/C). - 3/8/2012   10:51:23 AM
  • 31
    We keep the thermostat at 66 all winter. Since we have an unnsual amount of electrontics, I dare not lower it more. We also adjust the thermostat in the summer to keep the temps below 77...for the good of the computer equipment. - 3/8/2012   10:16:01 AM
  • GMAGEE
    30
    When I was young, I was like a lizard: I needed the sun to warm myself up and hated the cold. My husband was just the opposite: always internally warm. Once I went through menopause, I flipped: now I am internally warm and always turning down the thermostat (AND to keep consumption and costs down) and my hubby is again the opposite: internally cold! So, our battle over the thermostat setting continues, but I like the idea that keeping it chilly ramps up the metabolism. Maybe that's why I want to move to Maine. Thanks for the info! - 3/8/2012   9:09:01 AM
  • 29
    It seems appropriate to keep temperatures in one's home somewhat consistent with what's going on out of doors. I can see that some others commenting on this article are doing that as well.

    When I spent three winters in Himalayan India and Nepal, without indoor heating, temperatures were in the forties Farenheit indoors in winter, and I found that it took several days to adapt, but then I was comfortable at those temperatures by day (and, yes, my weight went down). The early days, when I was adapting, were not at all comfortable, and I'm not sure I would have made that adaptation if I had ready access to a warmer space, but people who are resisting lowering the thermostat because it's not comfortable right away might want to give it a few days.

    It doesn't seem necessary or appropriate to keep indoor temperatures that low now that I'm back in the U.S. but I keep indoor temperatures relatively low in winter, and high in summer. - 3/8/2012   8:07:04 AM
  • 28
    We've got our thermostat set to 65F during the day and 60F at night (and a space heater in our 14mth old's room) during the winter. We did it just for cost savings and that we both like it being a bit chilly. I too can't go to someone's house who has the thermostat set to higher than 70F. But we're completely opposite in the summer - we'll go without the A/C for as long as possible (until the muggy DC summer sets in), then we'll keep it at 80F during the day and 78F at night. - 3/8/2012   7:35:32 AM
  • 27
    I live in Southern China, where outdoor temperatures rarely dip below 45 F. Which sounded GREAT when I first found out my placement. Turns out, there's not really any indoor heating in Southern China. Especially in the building where I teach, indoor and outdoor temperatures are usually pretty much exactly the same - so while 45 F didn't sound so bad to someone who endured a few Northern Indiana winters - it is COLD COLD COLD here, and there's nothing I can do about it.

    So needless to say, this article makes me pretty happy! - 3/8/2012   7:27:48 AM
  • 26
    Very interesting I am wondering if this is why there are so many more obese people in the warmer climate states then the colder ones ? I know while I lived in Colorado most people I saw & knew were thin & healthy looking - 3/8/2012   7:26:12 AM
  • 25
    How about I have it off during the day and it can go as low as 60-55F before I turn it on, same with in the summer, I have it off as much as possible. However I have a little heater and a fan to help control the temperature of my bedroom or living room if the overall temperature is a bit uncomfortable. - 3/8/2012   6:29:48 AM
  • 24
    That is so funny. 65 degrees is way too cold for me (it's actually normal winter temperatures where I live),it would be a nightmare for me to live in these temperatures... - 3/8/2012   5:05:25 AM
  • PURDYLADY14
    23
    If I do get cold or hot usaually due to menopause (yuck) I will take advantage of the situation b walking around the hs, while doing chores on my tiptoes. I t is amazing how you can make your calves look better and stonger pluz burn calories at the same time,. Try for a week and see the difference, Goodluck you can do it , it is soooo easy. My husband even noticed, he said your calves and legs and look great what are you doing? My daughter does it also to make her calves stronger for soccer - 3/8/2012   4:38:49 AM
  • 22
    I didn't know this. I am always hot. I too like it in the low 60's indoors in winter. I rarely wear a coat and think you can get increasingly used to lower temps. I shovel the drive with no coat or gloves. Alaska fishermen don't even wear gloves when most people would get frost bit right away. bodies adapt. Another thing not mentioned. Viruses thrive in warm temps so the warmer your house, the greater chance of getting sick. - 3/8/2012   3:05:31 AM
  • 21
    I am always FREEZING. If it is 75 I am shaking from being so cold. I pile as many clothes and blankets on as possible when I'm home, but I need heat! I'm the total opposite in the summer unfortunately. I need it like 65 or I could swim in my own sweat. - 3/8/2012   1:37:33 AM
  • 20
    Oddly enough, each room in our home has its own thermostat. All are set a 60 during the winter (24 hours a day) except for my son's room - as far as I know he has kept it off almost all winter. - 3/7/2012   11:10:04 PM
  • 19
    I have never heard of brown fat before today. It's something I will need to look into. I generally like to keep my heat off, unless it is colder than 50 outside and then I just have the heat set to around 55 all the time. But the only reason I do this is because I'm a bit of a cheapskate. - 3/7/2012   8:33:00 PM
  • 18
    This is quite confusing for me. Yes, according to the charts, I am still in the obese category (but not for long!!) But according to this article, I do several things to increase the BAT. I walk all year long, even when it is cold. Seems like that should help alot. I know I have been carrying this weight around too long and it will not go away overnight, but shouldn't what I'm doing help get rid of some of this extra fat? Maybe I should just realize how far I have come, and I realize am a whole lot better off health wise than I was 6 years ago. - 3/7/2012   8:32:10 PM
  • 17
    interesting. - 3/7/2012   6:04:33 PM
  • 16
    In order to keep the cold bedroom at 66-68 degrees I have to set the thermostat in the warm hallway to 76 degrees. I am miserably cold at 68 degrees even wearing 3 shirts, my thickest pants, and bundled under 2 blankets and 2 cats while trying to read on the couch! - 3/7/2012   5:59:00 PM
  • 15
    When I was super obese (bmi over 52) I almost never felt cold. Now that I'm a "normal' weight I get cold much more easily.

    So, strangely enough, when I was at my heaviest I used to keep the thermostat at 55-60. These days I need it between 65 and 70. Even WITH extra clothes on. LOL

    And yeah, I exercise hard over 7 hours a week, and my % body fat is at or under 20, so I probably have as much BAT as I'm likely to have. I just get cold! - 3/7/2012   5:36:24 PM
  • 14
    Living in the frozen north where it is cold for up to 6 months, I do not like to be cold and keep our heat set at 72 most of the time. I think I will look for another way to burn that fat. - 3/7/2012   5:30:52 PM
  • 13
    Our house is about 64 at night and 60 during the day when we aren't home, then when we get home from work/school I turn it up to 67 but it takes about an hour for the house to heat up. I hate being cold. Even in 70 degree temps my hands are cold. This is interesting research I hadn't heard of before. Thanks for a cool blog. - 3/7/2012   5:12:25 PM
  • 12
    Wow, very interesting...I never heard of white and brown fat. I do keep my house cool in winter: 60-62 at night; 65-66 day. Mainly because I think it is healthier, cheaper, better for the environment and seems to make sense that you would burn more calories keeping warm. I must say though that I am often hungrier when I am cold. - 3/7/2012   2:45:43 PM
  • 11
    Well, I've always had this thought that your body must be expending more energy trying to keep your core warm in winter, but had no evidence to back it up.
    However, I never use a thermostat as whenever it gets really cold, I get up and do A hard Cardio workout to warm up and feel energetic to go to my college or study or whatever. I'd never get cold on purpose I'd rather just exercise which is more effective than staying cold. But in case you are really cold outside you can be slightly happier about it now knowing your BMR is raised I guess. - 3/7/2012   1:46:36 PM
  • 10
    Readers who are interested in reading more research on this should go to hypothermics.com and watch Ray Cronise's TED talk on the same subject. It's interesting stuff. I started learning about it last winter and I have lowered my thermostat, but the weight isn't falling off. Maybe because I pile on the fleece and wool socks? I hate being cold. - 3/7/2012   12:48:32 PM
  • 9
    I'm not usually affected much by the temperature until it gets somewhat extreme. Nights that it gets below 45F, I usually have to close my window. I don't control the thermostat in the house and my room only has a tiny vent at the far end of the room up near the ceiling (12' ceilings), so generally the temperature is based on the outside temp. I'm lucky to live in a temperate climate. (32F - 100F, with only a few days/nights at either extreme).

    In my previous apartment which had a whole A/C and heat duct system, summer thermostat was usually cool to 75-78F and winter thermostat was warm to 68-70F. (Most of that was a concession to my DDa who is very temperature sensitive and "freezing" if it's less than 70F. No, not just complaining. She's the kind with icy hands in summer - even if her circulation is okay.) - 3/7/2012   12:48:09 PM
  • 8
    Unfortunately (and fortunately), I don't have control of the heat in my apartment. (Unfortunate because I can't turn it down & we're usually roasting! Fortunate because I don't have to pay a gas bill!)

    I like to be a little cooler than most of my family. What's comfortable to me is too cold for most of them. I don't know if this helps me at all, though. I would really like to see/hear more about this, too. - 3/7/2012   12:22:26 PM
  • 7
    My husband hates to be cold, so here in Florida he rarely lets me adjust the temp from 80F for the A/C and 75F for the Heater. When he's not home though I turn off the Heater and if it's cool outside I open up all the windows and turn off the A/C. - 3/7/2012   12:06:15 PM
  • 6
    Right now I don't have a working heater (house). I have a tower that I move around in the house to keep me warm. My heater is going to cost me $5000. and I don't have them money to get it fixed. When it is working, I usually set it at 68 degrees. - 3/7/2012   11:58:03 AM
  • 5
    I tend to run hot most of the time, so I usually keep the thermostat at about 64 or lower in the winter. For the last few weeks, our apartment felt unbearably stuffy, so I've had the heat off and sometimes the windows open (closing them when it dips below 40). My poor husband runs cold most of the time, so we are always compromising on the temperature :) - 3/7/2012   11:42:25 AM
  • 4
    I heard this before and I tried it this winter, I kept the house at 66 durn the day and 67 at night, I was never really cold or hot so I am not sure if it worked or not
    - 3/7/2012   11:07:22 AM
  • CHANGINGK
    3
    This is very interesting. A got reason to keep it cooler in the winter and to keep moving! - 3/7/2012   10:56:53 AM
  • 2
    I am interested to see more research on this! - 3/7/2012   10:38:36 AM
  • 1
    I don't tend to get too cold in winter or in "cold" situations (like diving 4-5 times per day), so my heat in the house doesn't come on in winter until the temperature reaches 63F...that goes down at night to 60F, as well. In the summer, I can't afford to have the thermostat too much lower than 78F, because Texas summers are brutal, temperature-wise...but the automatic thermostat goes down to 72F for sleeping, about 11pm. - 3/7/2012   10:26:14 AM

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