Does Cardio Result in Muscle Loss?

Hi Davey

I was just wondering if doing a lot of cardio adversely affects muscle growth?


Hey Kyle,

Yes, doing excessive cardio can cause you to lose muscle. But you’d have to do A LOT of cardio to see any real reductions in muscle size. There’s no cut and dry definition for what “a lot” means – and it’s different for different people – but unless you’re doing more than 45 minutes – 60 minutes of cardio, you probably have nothing about which to worry.

Don’t let the fear of losing muscle prevent you from enjoying the many benefits of cardiovascular exercise including:

  • Fat loss
  • Stronger heart and lungs
  • Increased bone density
  • Reduced stress
  • Reduced risk of heart disease and some types of cancer
  • Temporary relief from depression and anxiety
  • More confidence about how you feel and how you look
  • Better sleep
  • More energy

Moreover, cardio can actually help with your strength training – it improves blood flow and oxygen transport to your muscles, which helps with muscle growth and recovery.

Muscle loss more often occurs if:

  • You’re not eating enough protein. Protein is the building block of muscle. Find out how much you should be eating.
  • You’re not eating enough carbs. Yup. Carbs are needed in the creation of muscles. This is why I recommend eating a slice of bread with a protein shake since so many shakes are low carb.
  • You are not eating enough calories. If you’re starving, your body will remove the tissue that burns the most calories: muscle.
  • You are not training with weights or strength training machines. If you don’t use it, you’ll lose it!

Hope that helps – and keep up the cardio!

About Davey Wavey

Davey Wavey is a certified personal trainer and YouTube sensation with more than 250 million video views. For Davey's fitness tips and secrets, sign up for his free monthly newsletter - or download any of his affordable and effective workout programs.


  1. wow thanks Davey, i needed that little bit of info too, since i finished Uni and all, ive been putting exercise back into my day to day life pattern.

    Love Jay xx

    peace out

  2. I don’t believe that any amount of cardio, short of ultra-marathoning perhaps, will cause one to lose muscle.

    On the other hand, a lot of cardio will make it harder to gain the weight necessary to get bigger muscles.

  3. davey… a slice of bread with a protein shake for carbs… booo!! boooo! better be whole grain bread… i figured that a banana or some almonds/mixed nuts, maybe some grapes or an apple would be a better source of COMPLEX carbs than a slice of wonder bread…
    ever wonder why its called wonder bread? – prolly cause after you eat it, you wonder why you would ever eat something as tasteless n empty as a slice of white bread… i wonder if wonder bread has any nutritional value?
    arent i wonder-ful?

    ~ cheers….

  4. David, all bread, white or whole grain, is composed of complex carbohydrates. A “complex carb” is merely a polysaccharides – that is, something composed of multiple glucose units linked together. Fruit, actually, is more “simple” than white bread, since it’s primarily fructose. Which is not to say that fruit is bad – just that bread and starch are frequently, and unfairly, demonized.

    As for the topic at hand, the body doesn’t tend to break down muscle tissue until glycogen stores have been depleted. For most people, a full supply of glycogen takes about 20 miles to exhaust. Your every day runner is so thin, not because they run, but because they don’t lift. The two disciplines can – and I think, should – live in happy harmony.

  5. I want to lose 10pz, I was wondering what can do. I worked out 2 hrs every day, I do deference types of work out , I run 5 miles, do aerobics, boot camp class , I am an a great shape , but still I am not losing any way … Help me please.

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  1. […] If you’re doing more than 45-minutes of cardio, you’re entering into the “danger zone” at which point your body will start burning muscle – not fat. […]