Fasted cardio and muscle loss

 

One of the biggest debates raging on the Internet is regarding cardiovascular exercise.

One person says it sucks and will burn all of your muscle mass while another says the complete opposite.

Then there are those who say that high intensity intervals are much better for burning fat compared to slower, steady state cardio.

Finally, you have the camp that claims cardio on an empty stomach is the way to go while another guru says that this is exactly what you shouldn’t do!

Arrrrggggggggg!!!!!

So what’s the answer?

Sorry to tell you but I have to say “it depends”!

Here is what I have found:

 

Will Cardio “Burn” Muscle?

The answer to this is….it depends. In some cases yes, long, never ending bouts of cardio (such as marathon running) will certainly consume some muscle tissue- particularly in the legs. I mean, have you EVER seen a marathoner with muscular wheels? Nope. How about a sprinter? You better believe it! Sprinting and other shorter burst, high intensity athletes will often sport tremendous musculature. This is not to say that the occasional run will make your legs into tooth picks. What I am saying is that if you like to run you better make sure you do some significant load bearing activity or you may find yourself skinnier than you want to be. On the other hand I have found that some cardio can do wonders to improving body composition and increasing endurance. The key here is striking a balance between performing cardio and resistance training.

 

High  Intensity Interval Training (H.I.I.T) vs. Steady State Cardio

Much has been written about this subject and rather than rehash what has already been said I prefer to provide you with my point of view based upon my experience with training my clients and myself.

While I am well aware of the increased EPOC effect that high intensity interval training provides I am yet to be convinced that this results in any measurable difference in body composition change when compared to a session of longer duration cardio that burns a similar amount of calories during the session. Therefore my take on this is that you should do both. I prefer to alternate between sessions of H.I.I.T and steady state (on separate days). In addition, I do believe that performing steady state cardio immediately following an H.I.I.T session may be the best of both worlds.

 

 Fasted vs. Non Fasted Cardio

At the moment the debate over this is raging with many folks tossing around scientific studies to support either argument. The funny thing is you can find a study to support pretty much anything these days. What matters most is what works for YOU and that tends to boil down to what you are able to actually do. That being said, here is what I have learned from my experience;

First, if you have the luxury of performing your exercise anytime you like then I would recommend that you perform steady state cardio on an empty stomach for fat loss (the low insulin levels found in a fasted state make for a favorable fat burning environment. If you are concerned about muscle loss you could consume 5-10 grams of BCAA’s prior. This will raise blood sugar but nothing compared to eating a full breakfast). If you prefer to do intervals I would recommend that you perform after you have eaten a meal or two. It just seems that performing H.I.I.T on an empty stomach is extremely tough and very stressful on the body whereas steady state cardio is a bit “easier” and doesn’t send your adrenals into a nosedive first thing in the morning (please check out my post on overtraining symptoms for more info).

My personal preference is to experiment with what works for each individual client. The three types to experiment with are:

  1. Steady state cardio performed either first thing in the morning or immediately following your resistance training session for approximately 20-40 minutes. You can also try performing this 3-4 hours after your weight training session.

 

  1. High Intensity Interval Training (H.I.I.T) performed on your off days from weight training after you have had a meal or two (wait at least 3 hours after eating).

 

  1. A combination of intervals plus steady state (10-12 minutes of intervals followed by 30 minutes of steady state) performed on your off days from weight training after you have had a meal or two (but at least 3 hours after eating).

 

It is VERY important that you experiment and keep track of what is working for your body. We are all different and no single program will work for every person.

Please let me know if you have any questions and have a super week!!

 

This post was written by

Bruce – who has written posts on Cutting edge muscle building and fat loss secrets.
bruce krahn is a best-selling author, writer, researcher, personal trainer and professional speaker. he has coached people for two decades both in person and online. he created this site to be an honest source of useful, practical information you can use to improve your health, build muscle, lose fat and get the lean body look.

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About

bruce krahn is a best-selling author, writer, researcher, personal trainer and professional speaker. he has coached people for two decades both in person and online. he created this site to be an honest source of useful, practical information you can use to improve your health, build muscle, lose fat and get the lean body look.

3 Responses to “Fasted cardio and muscle loss”

  1. Nac says:

    I hope this question is not too ridiculous but how quickly does muscle lost occur? For example, if out of ignorance, I do an hour of intense cardio for one hour during a 24 hour fast, will I lose muscle mass just because of that one day of fasted cardio?

    • admin says:

      This is an excellent question. Only in prolonged fasting does protein catabolism become an issue. This only happens after stored liver glycogen becomes depleted. If fasting is prolonged longer than 24 hours the body will begin to break down muscle to use as an energy source. This process may take longer to occur as it depends on how long it takes for your glycogen stores to be fully depleted. There is no problem with muscle loss during a 24 hour fast provided that you keep your protein intake high as part of your regular eating days (which you should be doing anyways).

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