Lots of cardio means losing muscle?

Mellie289

I keep seeing people posting comments to this effect. I don't understand and I hope someone can explain it. If I'm eating above my BMR with lots of protein 3-4 times a day, along with decent a decent amount of fat and carbs, getting a reasonable amount of micronutrients, why would cardio be detrimental to muscle maintenance?

I have lost almost 30 pounds, mainly through changing my eating habits to be mostly clean and gradually increasing my cardio loosely following the C25K program (over several months) to get to a 5K last month. I feel that I have developed my muscles more by doing this cardio workout. I definitely feel stronger, my lower back, which often has problems, has improved. I was really surprised to see people suggesting that cardio would cause muscle loss.

Maybe it's for longer workouts, like marathon training? Isn't there some element of strength training on the treadmill if you are carrying 30-60 extra pounds?

Thanks to anyone who can clarify this for me.

myofibril

It's not cardio directly which causes loss of muscle ~ it is excessive calorie deficits. The problem is that cardio can create such a state, especially low intensity steady state, which you can do for a number of hours each day without worrying too much about recovery. Therefore if you do not eat to support your training you will lose muscle.

Low calorie dieting + excessive amounts of cardio = bad idea.

It is true that cardio can cause muscle gain for a limited amount of time if you are new to training and calories deficits are not too steep as it introduces resistance (body weight) as a novel stimulus to muscle. Hypertrophy can be prompted in obese people simply by walking given how unused their muscles are to moving the load there is present due to their high body weight.

However, you have to remember that to keep muscle growing passed this short term initial spurt you have to keep exposing it to sufficiently greater loads than to which it is accustomed. The load which you use in cardio is body weight. As you get slimmer the load therefore goes down not up.

Therefore unless you fancy the idea of doing cardio with a weighted backpack or some other such contraption (which would be a very poor idea especially for your joints) it is far more efficient and productive to use a different form of resistance: barbells, plates etc.

Mellie289

Sorry if I've put this on the wrong board. I thought it was a question generally about losing weight versus muscle, but I think I should have posted this on the Fitness and Exercise board instead.

Mellie289

It's not cardio directly which causes loss of muscle ~ it is excessive calorie deficits. The problem is that cardio can create such a state, especially low intensity steady state, which you can do for a number of hours each day without worrying too much about recovery. Therefore if you do not eat to support your training you will lose muscle.

Low calorie dieting + excessive amounts of cardio = bad idea.

It is true that cardio can cause muscle gain for a limited amount of time if you are new to training and calories deficits are not too steep as it introduces resistance (body weight) as a novel stimulus to muscle. Hypertrophy can be prompted in obese people simply by walking given how unused their muscles are to moving the load there is present due to their high body weight.

However, you have to remember that to keep muscle growing passed this short term initial spurt you have to keep exposing it to sufficiently greater loads than to which it is accustomed. The load which you use in cardio is body weight. As you get slimmer the load therefore goes down not up.

Therefore unless you fancy the idea of doing cardio with a weighted backpack or some other such contraption (which would be a very poor idea especially for your joints) it is far more efficient and productive to use a different form of resistance: barbells, plates etc.

Oops! I didn't see this when I posted again. I should have refreshed my screen.

That makes sense to me. I was never aiming for an excessive calorie deficit from the outset -- just aiming for healthy eating and some activity.

As for increasing load on muscle, it's my thought (although I may be wrong here) that by increasing from walk to a jog, I am increasing the load on my muscles although my weight may be decreasing. So, 50 pounds excess weight and mostly walking versus 30 pounds excess weight and half jogging now would have a similar load on my legs.

And no, I don't fancy the idea of using a weighted backpack! :noway:

I see that if I dump more weight and I'm able to continue increasing my cardio stamina, I'll have to mindful of feeding my muscles and including some strength training. I have now started doing the 30 Day Shred, which will help.

Thanks for the very clear explanation!

myofibril

As for increasing load on muscle, it's my thought (although I may be wrong here) that by increasing from walk to a jog, I am increasing the load on my muscles although my weight may be decreasing. So, 50 pounds excess weight and mostly walking versus 30 pounds excess weight and half jogging now would have a similar load on my legs.

Unfortunately that won't really be enough by itself because there will be insufficient load and progression.

Personally, I think if one of your primary goals is to look good naked it is better to introduce some sort of resistance training sooner rather than later (and even in preference to most of the cardio.) However, these decisions are dictated by what your overall goals happen to be (obviously if your goal if to run a 10k or something that wouldn't be suitable.)

Good luck.

ETA: oops I overlooked your mention of 30ds! Whilst I don't think it is as efficient as a traditional weights routine it should certainly move you forwards in the right direction. Obviously keep your calorie deficit reasonable if preserving muscle is important.

thebaconbeast

I do cardio for around an hour to an hour and a half each day and I'm still building muscle.

Keep it a surplus.

Mellie289

Personally, I think if one of your primary goals is to look good naked it is better to introduce some sort of resistance training sooner rather than later (and even in preference to most of the cardio.) However, these decisions are dictated by what your overall goals happen to be (obviously if your goal if to run a 10k or something that wouldn't be suitable.

Good luck!

Yes, one of my goals is to run a 10K. I expect it will take me a while to get there. I will also try to increase my strength because that's got to help me be able to run longer, if my muscles are stronger, I would think.

Thanks!

Mellie289

I do cardio for around an hour to an hour and a half each day and I'm still building muscle.

Keep it a surplus.

Perfect! An hour is around what I'm aiming for right now for cardio time most days and a little more on the weekends to improve my run length. Thanks!

realme56

I did cardio through most of my 104# loss and light weights. I am at a plateau since May so I joined a reasonably priced gym and am adding weight training and did my first Zumba class. I think it should bump me off the plateau but I already feel stronger overall and am looking forward to a more defined body as well.

meshashesha2012

well as someone who hasnt been eating at a large calorie deficit, and who's workouts are primarily heavy weight lifting, it seems that 10% of my weight loss has been from lean body mass.

i think there will always be some amount of muscle loss when you eat at a calorie deficit over an extended amount of time. i think the only reason why i've had minimal LBM loss is because i lifted heavy the entire time. i'm sure had i have done nothing but cardio the entire time i would have lost a bigger percentage of LBM.

myofibril

i think there will always be some amount of muscle loss when you eat at a calorie deficit over an extended amount of time.

Yes, that is a good point. Over the long term you will generally lose some muscle along with fat and the game shifts to how to minimise that loss.

However, if you are new to training, overfat and a few other categories it is possible to increase muscle in the short term (but not a huge amount.)