How does cardio cause muscle loss?

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  • LolBroScience
    LolBroScience Posts: 4,537 Member
    skullshank wrote: »
    jenjay8045 wrote: »
    Its a load of rubbish promulgated by those who like to pick things up and put them down again. I have lost over 100lbs and believe me that was all fat. I now have more muscle than I have ever had and I haven't lifted anything. (Stands back and waits for flaming)


    Hehehee you are so dead on!!!!

    So... no activity done which would aid in retaining LBM, yet some LBM is being added?

    she then goes on to agree with the person stating "People who start out overweight/obese often have a lot of muscle (needed to carry around the excess pounds). A 300 lb person is literally carrying around 300 lbs every day. If that person starts losing weight, he's going to be carrying less and less. The muscles that were straining and working to carry around his frame (thus, working out those muscles), are no longer working as hard. He will lose that muscle slowly over time unless he adds resistance training designed to help him maintain some of that muscle. Muscle: if you don't use it, you lose it."

    Marty-McFly-Confused-In-Back-To-The-Future-Gif.gif

    I just want to give myself to opportunity to side with whoever may be correct! By responding to both, I have that chance!
  • LiftAllThePizzas
    LiftAllThePizzas Posts: 17,857 Member
    Its a load of rubbish promulgated by those who like to pick things up and put them down again. I have lost over 100lbs and believe me that was all fat. I now have more muscle than I have ever had and I haven't lifted anything. (Stands back and waits for flaming)

    That's what I've noticed around here... if you're not lifting you're doing it wrong. And will never be exercising correctly until you lift. As if there aren't any other types of exercises besides lifting. (...Waits for beheading. :laugh: )
    You are of course aware that there are different types of muscle fibers and that they are used under different conditions, right?
  • mustgetmuscles1
    mustgetmuscles1 Posts: 3,346 Member
    edited December 2014
    NextPage wrote: »
    Its a load of rubbish promulgated by those who like to pick things up and put them down again. I have lost over 100lbs and believe me that was all fat. I now have more muscle than I have ever had and I haven't lifted anything. (Stands back and waits for flaming)

    That's what I've noticed around here... if you're not lifting you're doing it wrong. And will never be exercising correctly until you lift. As if there aren't any other types of exercises besides lifting. (...Waits for beheading. :laugh: )

    This totally...... see my "I run" topic..... it was aimed at the same thing.


    Not everyone CAN lift though.... I can run till the cows come home....but lift anything & you will see me unable to move.

    Im not sure what your particular issue is to why you are unable to move but recommending strength training in addition to just cardio is not a bad thing. If you think it is just a bunch of meat heads telling people to do this then maybe you will find these link interesting.

    circ.ahajournals.org/content/101/7/828.full

    cdc.gov/physicalactivity/growingstronger/why/

    mayoclinic.org/healthy-living/fitness/in-depth/strength-training/art-20046670

    arthritistoday.org/about-arthritis/types-of-arthritis/rheumatoid-arthritis/daily-life/staying-active/strength-training-benefits.php

    ncbi.nlm.nih.gov/pubmed/14552938

    One is not better than the other and neither is all you need.

    mustgetmuscles - Thanks for posting this. It is strange that there are still women who don't understand that there are so many benefits to lifting.

    No problem but its not just women that resist the idea of resistance training.

    Bret Contreras just posted this article today. LOL perfect timing for this discussion. I like his answers better. Probably what most people were assuming anyways.

    bretcontreras.com/lift/
  • JeffseekingV
    JeffseekingV Posts: 3,165 Member
    They guy in the picture has around the same BF as me. But I'm at 170lbs.
  • ndj1979
    ndj1979 Posts: 29,136 Member
    jenjay8045 wrote: »
    Its a load of rubbish promulgated by those who like to pick things up and put them down again. I have lost over 100lbs and believe me that was all fat. I now have more muscle than I have ever had and I haven't lifted anything. (Stands back and waits for flaming)


    Hehehee you are so dead on!!!!

    So... no activity done which would aid in retaining LBM, yet some LBM is being added?

    don't forget the 100% efficiency of burning all fat and ZERO muscle...
  • NotGnarly
    NotGnarly Posts: 137 Member
    I've been running for a while, basically doing cardio only for months and have done cardio only off and on over the years. I accumulated a good amount of fat, would lose weight but still be in the same size clothes. I've lifted weights in the past also. The good thing about lifting weights is that I can lose inches and really see the difference in my body. I can touch my leg and feel the muscle, plus weight lifting speeds up my metabolism. I wear a bodymedia fit and according to it I burn the same amount of calories lifting weights as I do when I do cardio for 50 mins. The calorie burn at the end of the day is pretty much the same! but I feel way better after lifting weights.

    As far as answering your question OP which I forgot, sorry :/ I definitely think that lack of weight training over the years has contributed to me being able to acquire more fat on my body and decrease my lean muscle, thus slowing my metabolism. I went back to my personal trainers plan that I had years ago when I was able to lose weight. He had me lifting heavy weights, while limiting cardio (HR 130-150BPM) to 20 mins, working out 3 times a week. Cardio only just doesn't seem to work for my body, I've tried it many times and would lose 10 pounds and then nothing more, not even inches and yes this was while eating a deficit and staying on plan.

    My main goal this time around is to keep as much muscle as I can while shedding inches and fat, notice how I didn't say pounds lol. Pounds will come off eventually but my focus is progress measured by inches and bodyfat. Sorry for the rambling and I'm not sure if I answered your question.
  • PinkNinjaLaura
    PinkNinjaLaura Posts: 3,202 Member
    Lot of great answers here.

    Today was leg day! I have muscular legs, and I'm proud of them. I've worked hard for them. I do strength train 3x a week with a personal trainer (plus whatever homework he gives me for stuff we didn't get to). I'm also a runner, a biker, am working on becoming a swimmer, and I do Pilates. Why limit yourself where there are so many great ways to work out?

    I started running to burn calories and lose weight - could barely get through the 60 second intervals in the first week of C25K - and nobody was more surprised than I was when I started liking it. 13 months later I ran my first half marathon.

    I really believe it's the balance of both cardio & weight lifting that have helped me lose weight. My long runs are my therapy (plus a monster calorie burn when you run for a couple of hours), but lifting weights is my fun time. I just enjoy picking up heavy things & putting them back down again.
  • chrisdavey
    chrisdavey Posts: 9,834 Member
    KylaDenay wrote: »
    Is there a minimum of resistance/strength training that one needs per week in order to help maintain current muscle mass? I mean I know why I should do it, but I now prefer to run then lift weights. I was lifting 3 times a week months ago, but would 2 full body days be enough? Are body weight exercises enough when eating in a deficit?

    Only read first page so apologies if this has been answered. Typically, you can reduce volume by 2/3 of what you would require to gain LBM in a maintenance phase.

    Re OP:
    All exercise is catabolic in nature, some exercise promotes muscle protein synthesis (strength training) some exercise doesn't (LISS cardio). If it does, it is very minimal.

    BTW I was a cardio bunny during my large weight loss period and I can assure you that I DEFINITELY lost LBM. Only took me about 3 years to get it back. Cardio only is a bad idea.
  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
    edited December 2014
    SLHysell wrote: »
    I see it mentioned here often that when you focus on cardio when losing weight, you lose muscle and fat.

    This is the kind of 98 pound weakling a great diet and endless hours of intense cardio can turn you into...

    cristiano-ronaldo-real-madrid-shirtless-body-2010-2011-pre-season.jpg
  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
    SLHysell wrote: »
    Jams009 wrote: »
    It doesn't cause it, it just does little to prevent it, and in certain circumstances can increase it.

    Being in a calorie deficit causes muscle loss (as well as fat loss) and cardio increases that deficit making the loss occur faster.

    There's more to it than this, but one reason muscle is lost in a deficit is that muscle requires more energy to maintain than fat does. So when your body is in a calorie deficit it will burn muscle for energy as well as fat in order to reduce energy expenditure and therefore reduce the deficit.

    Weightlifting also increases calorie expenditure and therefore the deficit, but unlike cardio it also encourages your body to hold on to the muscle (it thinks it needs it).

    So a lot of people prefer weightlifting to cardio for fat loss.

    A bit of both would be the ideal; weightlifting to keep the muscle, cardio to increase calorie deficit.

    This is the most informative and thought out answer I've see so far. I bolded part of it because that is the part that I've always had a problem with. Why on earth would the body burn muscle instead of fat since fat's purpose is to store energy for use when we don't have fuel.

    It doesn't, until there isn't much fat left to burn. The less fat there is to burn, the more preferentially it will burn lightly used muscle, but at that point there is little enough fat left that dieting may have already come to an end.

  • mustgetmuscles1
    mustgetmuscles1 Posts: 3,346 Member
    edited December 2014
    Mr_Knight wrote: »
    SLHysell wrote: »
    I see it mentioned here often that when you focus on cardio when losing weight, you lose muscle and fat.

    This is the kind of 98 pound weakling a great diet and endless hours of intense cardio can turn you into...

    cristiano-ronaldo-real-madrid-shirtless-body-2010-2011-pre-season.jpg



    The cardio didnt burn off all his muscle but lets not pretend that it built it all either.

    cristiano-ronaldo-lifting-weights.jpg
    cristiano-ronaldo-573-on-the-gym-training-for-bodybuilder-showing-his-ripped-body-and-big-muscles-with-body-building-friend-2012-2013.jpg
    raulronaldo_indo
  • stealthq
    stealthq Posts: 4,298 Member
    Mr_Knight wrote: »
    SLHysell wrote: »
    Jams009 wrote: »
    It doesn't cause it, it just does little to prevent it, and in certain circumstances can increase it.

    Being in a calorie deficit causes muscle loss (as well as fat loss) and cardio increases that deficit making the loss occur faster.

    There's more to it than this, but one reason muscle is lost in a deficit is that muscle requires more energy to maintain than fat does. So when your body is in a calorie deficit it will burn muscle for energy as well as fat in order to reduce energy expenditure and therefore reduce the deficit.

    Weightlifting also increases calorie expenditure and therefore the deficit, but unlike cardio it also encourages your body to hold on to the muscle (it thinks it needs it).

    So a lot of people prefer weightlifting to cardio for fat loss.

    A bit of both would be the ideal; weightlifting to keep the muscle, cardio to increase calorie deficit.

    This is the most informative and thought out answer I've see so far. I bolded part of it because that is the part that I've always had a problem with. Why on earth would the body burn muscle instead of fat since fat's purpose is to store energy for use when we don't have fuel.

    It doesn't, until there isn't much fat left to burn. The less fat there is to burn, the more preferentially it will burn lightly used muscle, but at that point there is little enough fat left that dieting may have already come to an end.

    There's a couple of studies out there looking at retaining muscle mass in dieting pre-obese and obese individuals that seem to disagree unless you take diet into consideration.

    The studies were primarily looking at the effect of protein intake. Basically, if you eat enough protein test subjects did not lose a statistically significant amount of muscle. Those who ate low protein did lose a statistically significant amount of muscle mass even with plenty of fat left to lose.

    *disclaimer - I didn't spend much time going over the studies, so perhaps they were poorly run or have been contradicted ...
  • tigersword
    tigersword Posts: 8,059 Member
    Mr_Knight wrote: »
    SLHysell wrote: »
    I see it mentioned here often that when you focus on cardio when losing weight, you lose muscle and fat.

    This is the kind of 98 pound weakling a great diet and endless hours of intense cardio can turn you into...

    cristiano-ronaldo-real-madrid-shirtless-body-2010-2011-pre-season.jpg

    Right, because he doesn't spend just as many hours in the weight room. You're delusional if you think he doesn't.
  • ninerbuff
    ninerbuff Posts: 48,974 Member
    Its a load of rubbish promulgated by those who like to pick things up and put them down again. I have lost over 100lbs and believe me that was all fat. I now have more muscle than I have ever had and I haven't lifted anything. (Stands back and waits for flaming)
    Unfortunately that's not true. Anyone that loses weight WILL lose some muscle along with fat (unless you're using PED's and even then there's still some muscle loss). Just like adding muscle will involve adding fat, it works in reverse.

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  • ninerbuff
    ninerbuff Posts: 48,974 Member
    tigersword wrote: »
    It's basic physiology. The human body actually prefers to save fat and lose muscle in a starvation situation (yes, dieting is technically starvation.) This is because the body can live much longer with fat stores than without them.

    Average weight loss is about 75 % fat and 25% lean mass (muscle, water, bone, etc.) The larger the deficit, the more that ratio swings toward lean mass. Without proper fuel, cardio can lead to massive deficits that can lead to serious muscle loss.
    Pretty much this. It also is going to depend on whether or not one focuses on not losing muscle. Lots of leg endurance athletes don't do upper body work because they don't need the extra mass/weight and because they use little of their upper body strength to compete or do their preferred sport.
    As mentioned before, if the muscle isn't used and if deficits are high enough, then lean muscle gets reduced.

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  • ninerbuff
    ninerbuff Posts: 48,974 Member
    SLHysell wrote: »
    Jams009 wrote: »
    It doesn't cause it, it just does little to prevent it, and in certain circumstances can increase it.

    This probably sums it up best.
    If you want to do only cardio like treadmill, elliptical, or running, and you enjoy it and can maintain such a routine, and such a routine has caused you to lose weight..........then great, you're already doing more than the next person doing nothing.

    As far as the physiology behind your question. If, for instance, all you are doing is running, then over time you are going to become a more efficient runner. Unfortunately, your body is going to work to strengthen those muscles needed to run to create an improved economy of motion, but those muscles not used in your selected workout are going to atrophy.......you body will adapt to improve your selected method of exercise by burning the muscle no longer needed.

    Yes, if you maintain a calorie deficit, you are going to appear more muscular-ish, but that is because the fat that previously covered those muscles is burning too.......it's kind of a lose/win.......you're burning fat, but you're also burning muscle which is probably a greater component in burning fat than that 30 minute run you just did.

    In the end, do what you want, do what you can maintain and consistently do, and anybody who wishes to tell you you're doing wrong can just go away.

    This was helpful too. I think what you're saying is that running strengthens leg muscles, but doens't really do anything for the muscles that aren't really used much in running. That makes sense to me, but wouldn't the same apply to strength training? Calves and quads come immediately to mind. I'm guessing that legs kind of get the short end of the stick in strength training.
    Oh trust that there are many people in the gym who DON'T do leg work.

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  • ninerbuff
    ninerbuff Posts: 48,974 Member
    You can also target slow twitch muscles when lifting. It depends on how heavy you lift, your reps, etc. When lifting, you can consider whether or not you want to increase/maintain power, endurance, or strength. You don't always have to progressively overload.
    This is correct. BodyPump is a good example of endurance lifting.

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  • ninerbuff
    ninerbuff Posts: 48,974 Member
    Cardio is such a broad term. There are many exercises that are called cardio that also provide resistance.
    Just about every cardio exercise involves resistance. Whether it's running, biking, swimming,etc. The "degree" of resistance will help to dictate if it's more aerobic or anaerobic.

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  • ninerbuff
    ninerbuff Posts: 48,974 Member

    I do disagree that lifting a light weight 100 times could not build strength though.
    Strength is built on progressive overload and involves fast twitch muscle fibers. Lifting a light weight 100 is muscular endurance training and involves slow twitch muscle fibers.

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  • ninerbuff
    ninerbuff Posts: 48,974 Member
    There are three main aspects too fitness - Strength, speed and endurance.

    People seem to train the last two a lot and miss the first one.

    Flexibility. Even more important than speed.
    Depends on what you're comparing it to. Flexibility isn't as important in the 100 meter dash as it is to a ballet dancer. And vice versa when it comes to speed.

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  • ninerbuff
    ninerbuff Posts: 48,974 Member
    There are three main aspects too fitness - Strength, speed and endurance.

    People seem to train the last two a lot and miss the first one.

    I pulled my hamstring try to do HITT sprinting to improve 1)
    Imbalance in quad vs hamstring training. Most people pull hamstrings because they aren't trained as hard as quads.

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  • ninerbuff
    ninerbuff Posts: 48,974 Member
    tigersword wrote: »
    There are three main aspects too fitness - Strength, speed and endurance.

    People seem to train the last two a lot and miss the first one.

    Flexibility. Even more important than speed.

    I would actually venture to say flexibility is the most important (though also the most ignored) part of fitness. Most of the injuries I've read about (and experienced myself) were caused mainly by lack of flexibility leading to bad form and other mechanical issues that resulted in injury.
    I would say that good form on any exercise will lead to better flexibility. There are lots of female dancers who are extremely flexible, yet still squat incorrectly.

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  • heybales
    heybales Posts: 18,842 Member
    Keep the deficit reasonable enough, and you may need not have to worry about it at all.

    http://fampra.oxfordjournals.org/content/16/2/196.full

    "All three intervention groups had a significant decline in body mass at 6 weeks, and again at 12 weeks for an average total weight loss of 6.2 kg in the diet-only group, 6.8 kg for the diet plus aerobic exercise group, and 7.0 kg for the diet, aerobic and resistance training group (standard deviations only presented graphically). By 12 weeks there were also significant decreases in percentage body fat: 5.8, 8.0 and 4.3%, respectively. However, there were no significant differences between groups. There were no significant changes in fat-free mass in any of the groups at any time period. There were also no significant changes in resting metabolic rate (measured in absolute terms or relative to body mass) within groups over time or between groups over time. "

    "The findings regarding no loss of fat-free mass in the diet-only group are surprising, as some degree of obligatory loss of fat-free mass is expected with significant weight loss."

    "Much of the work regarding changes in fat-free mass and resting metabolic rate in response to hypocaloric diets have implemented diets containing 800–1200 kilocalories per day. Such low calorie diets result in a severe calorie deficit and the need to oxidize protein. Information regarding the participants' dietary intake in this study is scant. Only mean intakes per group for the entire 12-week period are presented. These intakes are approximately 250– 380 kilocalories less than mean baseline resting metabolic rates. In addition, dietary information is based on self-report, and there is a strong likelihood of underreporting of food intake in obese people.3 Systematic errors in this direction would lessen the actual calorie deficit. These relatively small calorie deficits may have enabled subjects to spare protein from oxidation."
  • tomatoey
    tomatoey Posts: 5,446 Member
    That's crazy. Thanks for sharing. Looks like the diet + aerobic group lost the most body fat % wise, interesting.
  • yopeeps025
    yopeeps025 Posts: 8,680 Member
    tomatoey wrote: »
    That's crazy. Thanks for sharing. Looks like the diet + aerobic group lost the most body fat % wise, interesting.

    That because of a larger calorie deficit. This group also lost the most LBM if there was no lifting of any kind.

  • jacksonpt
    jacksonpt Posts: 10,413 Member
    Jebuz.... this thread is still going???

    banghead.gif
  • heybales
    heybales Posts: 18,842 Member
    yopeeps025 wrote: »
    tomatoey wrote: »
    That's crazy. Thanks for sharing. Looks like the diet + aerobic group lost the most body fat % wise, interesting.

    That because of a larger calorie deficit. This group also lost the most LBM if there was no lifting of any kind.

    Actually, in the first study summary I quoted parts of - there was no loss of LBM.

    And since the weight lost was pretty close - there's not that much difference in calorie deficit. Since they were body matched too before random assignment to which group, even the deficit as a % of BMR was about the same (not the same as % of TDEE though). Over 12 weeks.

    "average total weight loss of 6.2 kg in the diet-only group, 6.8 kg for the diet plus aerobic exercise group, and 7.0 kg for the diet, aerobic and resistance training group"

    That would be a deficit of 570, 624, and 643 respectively, since they only lost fat, and using the 3500 cal/lb of fat. That's pretty close deficit amounts, within 11%.
  • NoelFigart1
    NoelFigart1 Posts: 1,276 Member
    edited December 2014
    ninerbuff wrote: »
    Just about every cardio exercise involves resistance. Whether it's running, biking, swimming,etc. The "degree" of resistance will help to dictate if it's more aerobic or anaerobic.

    Anecdotally, I do notice strength increases from time in the pool. Three months ago, it wasn't too easy to lift a 5 gallon water bottle and manipulate it onto the water cooler. Now, I'm throwing it around like it's nothing.

    Perhaps it is nothing compared to strength increases I would see pumping iron, but they exist.

  • ShrinkinMel
    ShrinkinMel Posts: 982 Member
    edited December 2014
    I think just because your deficit can get too high and you end up burning both fat and muscle mass. I'm sure it builds muscle in legs mostly but if you aren't eating back calories I can see how you could lose muscle too.
  • ninerbuff
    ninerbuff Posts: 48,974 Member
    ninerbuff wrote: »
    Just about every cardio exercise involves resistance. Whether it's running, biking, swimming,etc. The "degree" of resistance will help to dictate if it's more aerobic or anaerobic.

    Anecdotally, I do notice strength increases from time in the pool. Three months ago, it wasn't too easy to lift a 5 gallon water bottle and manipulate it onto the water cooler. Now, I'm throwing it around like it's nothing.

    Perhaps it is nothing compared to strength increases I would see pumping iron, but they exist.
    As I mentioned degree of resistance makes a difference. There's obviously more resistance in swimming vs running with nothing in your hands. The body adapts to resistance quite quickly which is why people stop getting DOMS if they lift the same resistance time in and time out consistently.


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