Advertise on Bikeforums.net



User Tag List

Results 1 to 22 of 22
  1. #1
    Junior Member
    Join Date
    Oct 2002
    Posts
    6
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    burning calories while at rest?

    Hello:

    Could someone explain to me the concept that the body is able to burn fat when not working out? I hear much info. from road cyclists that once the condition of the heart becomes outstanding the body learns to burn fat even when your not working out. Could anyone elaborate?

    Terry

  2. #2
    Huachuca Rider webist's Avatar
    Join Date
    Jun 2002
    Location
    Charlotte, NC
    My Bikes
    Fuji CCR1, Specialized Roubaix
    Posts
    4,274
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Our bodies have a basal rate of calorie consumption to maintain the functions of life. Our heart beating, lungs expanding and contracting, routine muscle movement and even maintaining our body temperature all require the expenditure of calories.

    Additional activity adds to the calories expended for basal rate activities. Should there be an overall deficit between calories consumed and calories used, we burn some combination of fat, protien and carbohydrates depending on the activity and the availablity of energy from these different sources. Consequently, if you have eaten normally and your blood and muscles have sufficient glycogen, these will tend to be burned earlier than will fat. Should there be a shortage of calories available from this prefered source, our body will turn to fat reserves even for the routine functions of simply staying alive.

    Of course, resting doesn't contribute much to fiteness and would be a rather slow way to lose weight
    Just Peddlin' Around

  3. #3
    Wood Licker Maelstrom's Avatar
    Join Date
    Apr 2002
    Location
    Whistler,BC
    My Bikes
    Transition Dirtbag, Kona Roast 2002 and specialized BMX
    Posts
    16,888
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Lean muscle helps this greatly. To go to an extreme a bodybuilder burns a trmendous amount of calories just sitting in place. So much so that when highly muscled you could avoid cardio to burn body fat. I forget the number of calories burned for every pound of muscle but it makes a signifigant difference. That is why when trying to loose 'bodyfat' (I hate the word weight) there should always be a muscle building section in your routine.

  4. #4
    cycle-powered nathank's Avatar
    Join Date
    Mar 2002
    Location
    Munich Germany (formerly Portland OR, Texas)
    My Bikes
    '02 Specialized FSR, '03 RM Slayer, '99 Raleigh R700, '97 Norco hartail, '89 Stumpjumper
    Posts
    1,848
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    i completely agree with both Webist and Maelstrom.

    the body's basic resting metabolism is determined by a number of factors, some genetic, some can be changed by trained and changing body composition. muscle mass is one of the major factors determining resting caloric usage. thus, adding muscle increases your resting caloric usage.

    so, it's kind of a slang use of it, but you can sort of say that by increasing muscle mass "you burn more fat while sitting or resting" because you will burn more calories and many may come from body fat. in weight training, some calories are used during the training, but the majority of the weight-loss/calorie burning benefits come in the weeks after training when the metabolism is increased from more muscle mass and more calories are burned even when at rest (and sleeping).

    also as the others posters said, weight-training is a very good part of a weight-loss program, because weight lifting will increase your muscle mass which increases your caloric usage EVEN WHEN NOT DOING EXERCISE.
    why drive when you can ride?
    now a fully certified German MTB Guide! (DAV)

  5. #5
    Just ride. roadbuzz's Avatar
    Join Date
    Oct 2000
    Location
    C-ville, Va
    Posts
    3,237
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I risk flamage here, but hopefully also some good discussion.

    It's my opinion that the body can become conditioned to burn fat, i.e. get better at it with practice, just like conditioning muscles. When your exercise duration is long enough to use up stored glycogen, and your effort level is such that you can't provide sufficient fuel by eating along the way, voila, your body has to turn to burning fat. Most serious cyclists frequently meet those requirements. As a result, our bodies get good at turning on the fat-burning mechanism, and can do it relatively painlessly even off the bike whenever the need arises.

  6. #6
    Senior Member
    Join Date
    May 2002
    Posts
    1,086
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I agree with what your saying but feel you may have oversimplified it.At the risk of oversimplifying this myself let me add I agree you get more efficient at burning fat at increasingly higher levels of intensity through training but you do this while also using stored carbs (glycogen)the result being the glycogen is spared and it takes longer to deplete.However when it does deplete for well conditioned cyclists with low bodyfat levels particularly a crisis/famine response occurs and the body tends to try to horde remaining fat stores by tearing down muscle/protein for fuel.I'm sure training improves your ability to better utilize both sources and keep going but at lower intensity since these are relatively inefficient fuel sources.As to post training I think the effect your refering to is probably the raised metabolism effect that exercise(the more intense the more effective)has causing you to continue to burn elevated fat levels post exercise(fat is actually a preferred fuel of such low activity resting states).Any increased muscle mass as previously stated raises fat metabolism as well.

  7. #7
    Senior Member Greg's Avatar
    Join Date
    Dec 1999
    Location
    Southern California
    Posts
    771
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    I've seen yogi's sweating their a$$ off while deep in meditation with nearly no perceptable heart rate.

    Find your mantra.

  8. #8
    cycle-powered nathank's Avatar
    Join Date
    Mar 2002
    Location
    Munich Germany (formerly Portland OR, Texas)
    My Bikes
    '02 Specialized FSR, '03 RM Slayer, '99 Raleigh R700, '97 Norco hartail, '89 Stumpjumper
    Posts
    1,848
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    roadbuzz and RWTD,

    i agree too... through training the body improves it's ability to use stored fat (and just to convert calories to energy in general and deal with lactic acid, etc)... but as stated, the risk is that the body might also convert muscle tissue into energy which is usually not a wanted side-affect.

    i usually do lots of weight training in the winter and put on muscle mass (i still do some cardio but my fat increases a little - usually about 165-170lbs and say 11% body fat). then in the summer i ride so much that i loose almost all extra fat as well as some muscle (usually 158-164lbs and say 7-8% body fat - even less in years past but now i'm 32)...

    i'm currently near the end of the season and i haven't been on a scale recently, but i think i am under 160!
    why drive when you can ride?
    now a fully certified German MTB Guide! (DAV)

  9. #9
    Just ride. roadbuzz's Avatar
    Join Date
    Oct 2000
    Location
    C-ville, Va
    Posts
    3,237
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Originally posted by RWTD
    IAs to post training I think the effect your refering to is probably the raised metabolism effect that exercise(the more intense the more effective)has causing you to continue to burn elevated fat levels post exercise
    I intentionally left out the burning muscle for fuel issue because I think it only becomes an issue in fairly extreme cases. And, yes, I oversimplified to help disguise any lack of expertise and because I don't like to type.

    Increased muscle mass and raised metabolism definitely contribute to increased fat metabolism, and may even be the main contributors, but that's not what I'm talking about. So let me back up.

    The typical American couch potato (canucks... is there such a thing as a chesterfield potato?) never has to burn fat, and more often is adding it. So, it's a pretty painful process when, due to diet or exercise, they have to dip into fat reserves. Endurance athletes do it like throwing a switch... no biggie. Need fuel, burn fat. Add to that endurance athletes are typically closer to "running on empty," i.e. we probably don't have as many spare calories working their way through our gastro-intestinal tract at any given time as our potato counterparts. So we're more likely to have to dip into fat reserves even while not exercising. Your body gets better at using fat when glycogen is short.

  10. #10
    Senior Member mike's Avatar
    Join Date
    Jul 2000
    Location
    Snowy midwest
    Posts
    5,392
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You CAN burn calories while at rest. Just breath fast and hard. Well, maybe it isn't exactly resting, but it will help you burn calories.

    The expression 'burning' is actually quite accurate. Burning defined as 'reacting chemically with oxygen' is exactly what happens when you burn calories.

    By breathing more, you help bring O2 into your lungs where much of the exchange takes place.
    Mike

  11. #11
    Senior Member
    Join Date
    May 2002
    Posts
    1,086
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    roadbuzz I reread your original post and I think I misread it to imply you only burned carbs first and then fat but that appears not to be what you were saying and that you were only focusing on the fat metabolism effects which I absolutely agree with including your second post so I apoligize.I think the only valid clarification I and nathank made was there is a cost in muscle loss training with depleted glycogen which as you said you just did not focus on.By the way due to muscle memory it is much easy to gain back than it was to gain the first time FWIW.

  12. #12
    Just ride. roadbuzz's Avatar
    Join Date
    Oct 2000
    Location
    C-ville, Va
    Posts
    3,237
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Originally posted by nathank
    the risk is that the body might also convert muscle tissue into energy which is usually not a wanted side-affect.
    I'm still not clear on this... can someone elaborate?

    This makes it sound like you will consume muscle tissue as well as fat once the ready supply of glycogen is consumed. Is that the case even in the presence of adequate fat reserves? And if so, what proportions of each?

    [unscientific rant]
    It just seems to run counter to what I would expect in terms of evolutionary development of the human organism. Fat is calorie storage and, what, insulation? Period. Muscle is, well, muscle. It and the brain get the job done. Hardly disposable, I would think, except as a last resort.
    [/unscientific rant]

  13. #13
    cycle-powered nathank's Avatar
    Join Date
    Mar 2002
    Location
    Munich Germany (formerly Portland OR, Texas)
    My Bikes
    '02 Specialized FSR, '03 RM Slayer, '99 Raleigh R700, '97 Norco hartail, '89 Stumpjumper
    Posts
    1,848
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It just seems to run counter to what I would expect in terms of evolutionary development of the human organism. Fat is calorie storage and, what, insulation? Period. Muscle is, well, muscle. It and the brain get the job done. Hardly disposable, I would think, except as a last resort.
    to the contrary... for the majority of human evolution food was not an abundant thing as it is today and lack of food was one of the main dangers/causes of death. thus, the body has evolved to store fat which as i understand is a very effective storage AND provides insulation. in survival situations it makes sense to burn muscle instead of fat b/c by buring the muscle you lower the caloric requirements for the future since muscles need energy to be maintained...

    as to:
    I'm still not clear on this... can someone elaborate?

    This makes it sound like you will consume muscle tissue as well as fat once the ready supply of glycogen is consumed. Is that the case even in the presence of adequate fat reserves? And if so, what proportions of each?
    this is getting beyond my area here, but yes, that's what i understand to be the case (i.e. that the body will burn BOTH muscle and fat tissues), but as to the proportions i don't know. i think it is a variable process - e.g. usually mostly fat burned but if the body is frequently in "starvation scenarios" then i think the body will adapt to be more likely to burn muscle to protect survival, but i'm just making an educated guess here. anyone know something more? (i'm too lazy to search the web - and i need to work here!)

    oh, yeah, unless you're doing something weird like starving yourself or making yourself bonk all the time or have major blood-sugar highs and lows i don't think your body will burn much muscle tissue. i think you will have the "starving feeling" for a while before any appreciable amount of muscle is converted for energy... it's a survival mechanism.
    why drive when you can ride?
    now a fully certified German MTB Guide! (DAV)

  14. #14
    Senior Member
    Join Date
    May 2002
    Posts
    1,086
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Like nathank my understanding of these issues are more broadbased/general than detailed/specific and I also agree with his answers.I think additionlly your available percentages of muscle/bodyfat and metabolism will affect this as well.For example very overweight people can go on very low calorie diets and lose bodyfat rapidly(with exercise)down to about 12-15 % bodyfat and then they "hit a wall"and fat loss stops(unless they adjust calories upward and use other fat loss strategies).This is the survival response kicking in . Similarly very muscular bodybuilders avoid aerobics like the plague(unless cutting for a show where the muscle loss is exspected and tolerated) because they are very suceptable to muscle loss since they have an aboundance.I myself used to train solely for endurance and think I was an expert at using bodyfat,muscle etc. for fuel as I didn't focus much on diet then and never had much of an appetite.Not surprisingly I was always around 155lbs with not much muscle mass(except maybe calves and hams) which I could never figure out.Since then I dropped the endurance,focused on diet and weight training normalizing and increasing the calories and now I have gained over20lbs of muscle at a lower level of bodyfat(which was never very high).In the last 6 months I have added cycling into the mix in a bigger way than before but when I push it to endurance levels(which I am definately doing now) I have to greatly increase calories and avoid running low on glycogen or I will rapidly shed muscle mass.I have gotten a little sidetracked here but my point which I think nathank also confirmed is if you are regularly training with low or depleted glycogen(particularly at bodyfat levels less than 15%or so) as most endurance atheletes do the risk of muscle loss is great as the body will attempt to protect remaining fat stores for the reason nathank explained above.He is also correct I think in that calories would have to be restricted for several weeks before significant muscle loss occurs .

  15. #15
    Huachuca Rider webist's Avatar
    Join Date
    Jun 2002
    Location
    Charlotte, NC
    My Bikes
    Fuji CCR1, Specialized Roubaix
    Posts
    4,274
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    This issue is quite complex and difficult to deal with in a single post. The human body is well designed and adapts quite well to circumstances.

    Food consumption results in the production of glycogen which is stored in muscle tissue and the blood until there is "enough." Then, through a somewhat longer and more complicated process, the remainder is stored as fat. A portion of the nutrients, during the same process, are used to build and maintain the structure of our body and to operate its active systems including muscle of course.

    Though not precisely, or in exact order, the reverse is more or less true when we use the stored energy. Yanking your arm away from a hot stove is accomplished by the energy stored winthin the muscles used. Quick and dirty and over almost immediately. However, that energy must now be replenished just in case you need to do that again. The replacement comes essentially from the blood. Again, replensihment is necessary. With any luck, the body finds food being processed and uses it. Should that not be the case, then it will look to energy stored earlier as fat and use it.

    Now let's suggest that we are waving that arm back and forth like we were the grand marshall of a long parade. The first couple of waves the body gets energy from the stored sugar in the muscle again replenished from the sugar in the blood. However, e are now asking the body to keep this up for a long priod of time. So, in order to preserve all these more readily available sugar stores, just in case you have to suddenly jump out of the car, the body goes to fat stores for long term activity. It uses the fat stores to replenish the sugars in the blood as well as the muscle and to provide the long term energy for this gentle activity. The same is true when you are taking a long easy ride on the cycle.

    Should there not be enough energy stored in the muscle and blood and you are calling on your body to do sustained very strenuous activity, like running away from a fire, or sprinting during interval training, your body's system concludes that you must be doing these things for a good reason and will do everything it can to sustain that activity for as long as possible, even if it means it needs to draw energy from your muscle protien to keep it up. Likewise, even for sustained activities of lesser intensity, such as breathing and maintaining body temperature, should your body not find sufficient blood or muscle sugars, fat stores or available food being processed, it will begin to claim muscle tissue to sustain life.

    All of these survival choices are made by our body based on the level and duration of the activity we are aksing it to sustain. When the acvivity settles to a more reasonable pace, the process of removing waste, rebuilding damaged tissue and storing energy is taken up again.

    If these processes operate correctly, you will always have the energy to yank your hand away from a fire because your body is trying to keep itself prepared for that need even while working hard at whatever else you may be asking of it.
    Just Peddlin' Around

  16. #16
    Just ride. roadbuzz's Avatar
    Join Date
    Oct 2000
    Location
    C-ville, Va
    Posts
    3,237
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks everyone for the informative posts. It's finally making sense. I think what I was missing is that the body isn't using muscle tissue as a calorie source, it's using it as a protein source. Can't get that from fat. Doh!

    Webist: interesting analogies, but Grand Marshall?

  17. #17
    Senior Member
    Join Date
    May 2002
    Posts
    1,086
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Just to further confuse you the body is in this case then breaking that protein into amino acids and amino acids into glucose for energy use.The branched chain AA's in particular are often converted for energy needs which is why bodybuilders often load up on them after a strenuous workout.

  18. #18
    cycle-powered nathank's Avatar
    Join Date
    Mar 2002
    Location
    Munich Germany (formerly Portland OR, Texas)
    My Bikes
    '02 Specialized FSR, '03 RM Slayer, '99 Raleigh R700, '97 Norco hartail, '89 Stumpjumper
    Posts
    1,848
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It's finally making sense. I think what I was missing is that the body isn't using muscle tissue as a calorie source, it's using it as a protein source. Can't get that from fat. Doh!
    roadbuzz,

    actually, i don't think that's right... in the case we've been discussing, the body is "burning muscle" for energy, or breaking down the muscle to provide energy.

    i think i agree with almost all of what both webist and RWTD said...

    unless you're into body building or for some other reason trying to keep your body fat really low, say 8% or less, and you're not frequently starving yourself, shouldn't be too bad...

    i personally do lots of weight lifting in the winter (2-4 days per week) and then in the summer less weight training and tons of cycling and running - during the summer i loose BOTH muscle and fat and my body-fat percentage stays pretty close to constant (slightly less in summer) although my weight varies from near 170 in the winter to just below 160 in the summer... with body fat around 9% these days (i'm 6'1" and 32 years old and my body fat % used to be a LOT lower although i find i have more energy reserves in races and bonk less without the ultra-low sub-8% body fat) (i'm kind of guessing on my fat numbers as i haven't had a lab test in a while although one of those not-so-reliable electric resistance ones in the spring measured 10%)
    why drive when you can ride?
    now a fully certified German MTB Guide! (DAV)

  19. #19
    Just ride. roadbuzz's Avatar
    Join Date
    Oct 2000
    Location
    C-ville, Va
    Posts
    3,237
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Well, after the discussion here, I decided to see if there was anything about it in any of my cycling books. The only thing I found was in Joe Friel's Cyclist's Training Bible. There's a chapter on nutrition, with a small section on protein. His point is that intense endurance work uses significant protein (up to 30 grams in an intense 1 hr criterium, for example). The main gist, as I understand it, is to make sure you get adequate protein, so your body won't have to cannibalise muscle tissue. If you have the book, check it out. He's got some other studies, etc., that he's basing his information on. Disclaimer: Joe Friel is a coach, not a doctor or nutrition researcher.

    So, I'm not necessarily disagreeing, but protein may also be a reason the body burns muscle tissue.
    Last edited by roadbuzz; 10-15-02 at 11:16 AM.

  20. #20
    Senior Member
    Join Date
    May 2002
    Posts
    1,086
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I agree mostly with what this coach is saying but let me add this.If you are talking about muscle gain/loss it is helpful to look at it in terms of the body being in an anabolic state promoting muscle growth or a catabolic state promoting muscle loss.In a catabolic state the muscle will be starved of nutrients such as water,glycogen, and others that volumize it while the body will have a reduced pool of free amino acids circulating while also having high energy demands .This is the state aerobics presents and at this extreme particularly if it happens regularly the muscle will tend to be cannabolized for fuel. What I am saying is the best way to guard against it is not to let any of this depletion occur(or limit it) through proper nutrition while training which includes protein (which in this case would be used as fuel in preference to the muscle )but also water,carbs etc. .Now if say the cycling is more anaerobic it will still be catabolic to the muscle but will also tend to tear it down in a way that sends signals such that with proper protein and rest afterward it will be built up stronger afterwards while in an anabolic state (promoted by the growth stimulus adequate protein and other nutrients to revolumize the muscle and rest) so that the body can better cope with this stress next time.The concern is about muscle loss during aerobics (carried to endurance limits regularly)where no growth stimulus to rebuild it exists and it is being cannabolized for energy use.So I guess I'm saying I agree with your last post but keep in mind that protein is being used mostly for energy.
    Last edited by RWTD; 10-15-02 at 01:25 PM.

  21. #21
    Just ride. roadbuzz's Avatar
    Join Date
    Oct 2000
    Location
    C-ville, Va
    Posts
    3,237
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Wow.

    Thanks to all of you for taking the time with the great posts. This has been really educational to me (although I think we've left Terry and his original question somewhere in the dust).

  22. #22
    Senior Member
    Join Date
    May 2002
    Posts
    1,086
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Just to balance this somewhat let me add that aerobic endurance does develop the oxygen carrying /energy generating capasity of the muscle at the expense of size/strength of the muscle.So it really is a case the muscle adapting for how it is trained .But as you mention we are far off the original topic though I think it has been answered very well earlier.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •