Does cardio burn muscle? – Team Fighting Fit

Does cardio burn muscle?

“Hey aerobics, the 1980s called and they want you back!”

That seems to be the mantra around the health and fitness circles these days. A lot of coaches, athletes and experts seem to be labelling Aerobic activity such as jogging on the treadmill as an exercise that should be a thing of the past.

I myself also tell my clients that, in order to burn more fat and build lean muscle, the emphasis should be placed on resistance training rather than aerobic training but I wanted to know whether or not Aerobic training had any place in a person’s exercise regime.

So, I wanted to use an anecdotal example and who better to use than myself.

In my early to late 20s, the bulk of my training was aerobic based. Apart from fight training which is very Anaerobic, I would do a lot of running and fitness training based on aerobic components such as stationary bike training, road running, treadmill running and elliptical training under the impression that not only would aerobic training condition me as an athlete to be fitter, but it would keep me leaner too.

Fast forward to 2012, My comeback fight after a few years of inactivity and laziness after knee surgery. I was a few weeks out from the fight and out for my morning run. Calamity struck as my knee started to hurt bringing back a lot of bad memories. After hobbling home and wondering what to do about the fight, I decided to change my training and work around the injury.

I started to focus on more high intensity interval workouts and strength and conditioning principles used by MMA fighters. Lots of Tabata training, hill sprints and HIIT training with strength training and weights thrown in.

I stopped doing Aerobic based training altogether other than what we do at Kickboxing class and the result was interesting. So, yeah, before I could run half marathons without getting tired and was fairly fit when fighting but I had no muscle definition.

I noticed two changes from my protocol.

Firstly, I had a bit of muscle definition! And screw that, I could even see my properly for once! And secondly (and more importantly), I felt fitter and stronger than ever before! I was convinced. Aerobic training was not for me and all I’ve really focussed on since has been cardio training based around High Intensity Interval training protocols such as hurricanes, tabatas and sprints.

So, let’s go back to Aerobic training and Anaerobic training.

Let’s define the two.

My definition of Aerobic training is sustained activity within your aerobic threshold whereby you’re exerting yourself but still able to talk and hold a conversation. You’d probably agree because it’s a pretty textbook definition for the lay person. Anaerobic therefore would be bouts of high intensity exertion where a conversation could not be held and you were “feeling the burn” (Reaching your Anaerobic/lactate threshold for the nerds amongst us – of which I am before you have a go at me)

Aerobic activity utilises Carbohydrates, fats and proteins for energy and at lower intensities, fat is the main source of energy hence why people interested in fat loss were told aerobics is the way forward unlike anaerobic activity which primarily utilises the glycolitic pathway (i.e. using carbohydrates for energy)

In fact, it was stated that working within lower heart rate zones of around 50-70 percent (low to moderate intensity cardiovascular exercise) put you in something called the fat burning zone/

All sounds good so far right? I mean, I you want to burn more fat, don’t exercise too hard right?

Well not entirely, the trouble with this concept of the “fat burning zone” is that whilst more fat is utilized for fuel at lower intensities and at rest, a lower amount of total calories are also being burned meaning that you don’t actually need as much fuel as if you’re doing higher intensity exercise.

Higher intensity exercise doesn’t mean you go completely stop burning fat for fuel either, there’s still a percentage of fat being burned alongside carbohydrates, it’s just that the higher the intensity increases, the more percentage of carbohydrates for fuel are used.

And the other problem with lower intensity, aerobic exercise is that long bouts of endurance activity has shown to have a negative effect on testosterone levels. This doesn’t just mean you’ll be limp in the bedroom but it means bad news for anyone wanting to pack on muscle and as we know, muscle increases your overall fat burning potential. In fact, a recent study showed that marathon runners were far more likely to gain body fat off season than any other type of athlete, this probably has a lot to do with their lack of testosterone.

So should you avoid aerobics altogether?

No, not entirely. In fact a combination of endurance and resistance training has been shown to be more beneficial than just resistance training on its own. A recent study was conducted where a group of men would perform leg extensions followed by a 30-45 minute bike ride using just one leg. At the end of the experiments, results showed more muscle volume and mass in the leg that performed both the cardio and the resistance training.

Cardiovascular training is known to improve the number of capillaries and vascularity of blood vessels so it’s no surprise that there was more muscle volume in the leg that did the cardio as the increased flow of blood meant more nutrients and oxygen being delivered to the muscles.

The take home message from this is that cardiovascular plays an important part in our overall health and fitness and can actually help if your goal is to gain muscle mass, it just needs to be done in balance. A bout of 30-45 minutes of cardio a few times a week will probably not hinder muscle growth especially when you’re providing your body with enough calories, nutrients and recovery time however, the tables can turn if more cardio is done than resistance training. This is due to something known as adaptation. In other words, your body and muscles adapt to optimise according to the stress placed on them. This is why you will find a marathon runner looks very different from a sprinter.

In terms of cardiovascular, fat burning potential and anaerobic muscle adaptations, nothing in my opinion beats High intensity interval training (the effects on testosterone and other hormones as a result of HIIT favour an anabolic environment in the body – i.e. the body burns fat and builds muscle. The caveat here is to not over train and to ensure adequate caloric intake and positive nitrogen balance through eating protein) however, with that being said, a couple of recovery runs or long slow distance cardiovascular training for 30-45 minutes a session would probably do no harm to your muscle gains.

About the Author

Hi, I am Fahad and I am passionate about fitness, combat sports and personal development. I have combined those three things with my mission of helping people live kick ass lives and created Team Fighting Fit. A training program and community to help you achieve your goals in half the time!

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