How does cardio cause muscle loss?

LolBroScience wrote: »

jenjay8045 wrote: »

prdavies1949 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?

mustgetmuscles1 wrote: »

pinkraynedropjacki wrote: »

Lasmartchika wrote: »

prdavies1949 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.

"I can run till the cows come home....but lift anything & you will see me unable to move." This reminds me of some of the success stories that I have read where OP states that when they started running they could barely make it around their block without feeling like they were about to die - 6 months later they are doing 10Ks and loving it. The same approach works for starting to lift - research, learn technique, have the courage to start and work progressively harder to see results. The only reason you can't lift is that you haven't started and perhaps you don't want to, but I doubt it is a "can't" scenario. Lifters wouldn't advocate you start with lifting weights so heavy you are immobilized anymore than you would suggest someone run a marathon without any preparation.

SteveJWatson 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.

SLHysell wrote: »

jeremywm1977 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.

LolBroScience wrote: »

jenjay8045 wrote: »

prdavies1949 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."

Lasmartchika wrote: »

prdavies1949 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: )

You are of course aware that there are different types of muscle fibers and that they are used under different conditions, right?

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.

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.

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.