Does Cardio Burn Muscle or Fat First?

Cardio is one of the most essential pieces to a healthy lifestyle. All types of people will perform cardio exercises, from elite athletes in their prime to the elderly as a way to keep up a good heart rate. However, despite the obvious benefits, there are questions surrounding cardio as well.

Does cardio burn muscle or fat first? Cardio will burn fat before muscle, and if cardio is starting to burn muscle, you’ve either developed a severely poor diet, or you are performing cardio at too high of a pace or too long of a time. Burning muscle also can come from exhaustion as well in some cases.

Today, we’ll be looking at the effectiveness of cardio, as well as how you should be training. We’ll also be exploring the various types of cardio, as well.

Why Does Cardio Burn Fat First?

Cardio and “fat-burning” exercises go hand and hand, and for good reason. The first energy source that will be burnt is glucose; then fat is the next option the body will burn for energy.

This is why cardio is one of the most effective types of exercises for people who are trying to lose weight. However, as with anything, you can overtrain cardio, and that can have some bad side effects, which we’ll be touching on a bit later.

However, if you are looking to shed some fat off of your body, cardio and a healthy diet will become your closest friends. The types of exercises you will do depend on what exactly your goals are, but as long as you push the pace and break a good sweat, you should do just fine.

How Effective is Cardio?

Overall, cardio is a necessity for a healthy lifestyle. As with anything, it needs a healthy balance. Cardio varies drastically on your personal fitness goals and what you are trying to achieve.

For example, if you are a soccer athlete, then you’ll have a heavy focus on cardio in your training, as it is a huge part of being successful at the sport. On the other side, if you are, for example, a lineman in football, then you’ll have much more of a focus on strength.

That isn’t to say that you won’t train one or the other, as to be the most effective athlete or just to be in optimal shape, you need to do both strength and conditioning. However, there certainly will be different levels that are geared towards cardio just depending on the person and what their goals are.

Best Types of Cardio

Fitness experts will argue back and forth on what type of cardio is the most effective, but it mainly depends on your goals in fitness and/or in sport. For example, going as hard as you can at something for short bursts is great if you are training for quick sprints and/or quick plays.

A great example of this would be a goalie, such as in hockey. They aren’t focused too much on long-term cardio, rather, short, explosive movements to save the puck. With that in mind, their methods for cardio training may not be effective for a cross-country runner.

Long-distance runners will focus on long cardio sessions, following a particular pace for x amount of time.

However, if you are not an athlete and/or not training for sport, but rather for fitness, then cardio sessions may look different for you. If that is the case, I recommend accomplishing simple cardio workouts first, like running and biking, but we’ll cover that a bit more in detail later.

How Can Cardio be Negative?

Even though I recommend cardio in practically training plans, there can be times where you overtrain in that area. This can cause issues such as fatigue. Personally, I’ve experienced this and had to give my body the proper time to rest and recover.

However, if you don’t focus on the recovery aspect, then you’ll find yourself at more risk, such as starting to burn muscle. This is in extreme cases but has certainly happened. Many people who love to work hard in the gym sometimes don’t know when to give their body a rest, and will ultimately lose the progress they’ve been striving for, simply by overworking themselves.

Proper recovery is crucial in order to make sure that you breakthrough to new gains and milestones in your fitness journey, which can be hard to comprehend, especially if you are hard-headed like myself.

How Do I Know What Type of Cardio is Right For Me?

Knowing what type of cardio sessions to do can be crucial, primarily for athletes. If you have a strength & conditioning coach, I’d recommend following their instructions. However, if you don’t, researching your position and sport and what the top athletes do is a great place to start.

Now, if you are looking to do cardio training to shred off some weight or just to help yourself stay in shape, there are many exercises that I recommend trying out. Some of my personal favorites are:




Row machine

Assault Bike

Ski erg

Balancing Weights & Cardio

To this very day, there are countless debates about how one should split up doing cardio and weights. New methods of exercise such as “CrossFit” have made high-intensity workouts that require great cardio in all aspects of the workout, not just one.

However, there are still many people that will train more traditional, but doing weights slow and controlled, and having specific days where they focus on cardio. Personally, if you are just starting out, I’d recommend getting comfortable with performing lifts and starting to run and such before jumping into something like CrossFit. Although many fitness programs are welcoming to newcomers, I think people will perform better once they’ve built confidence up.

However, if you are more experienced in a gym or fitness setting, then I think trying something out like CrossFit is a great way to challenge yourself.

The important thing when it comes to balancing weight and cardio is to make sure that you listen to your body. If your knee is really bothering you one day, don’t force yourself to go run, instead, hop on a row machine or focus on upper-body lifts.

This is an example of weights & Cardio (Follow Along)

Proper Nutrition

Another necessity for being in good shape is, of course, what you are putting into your body. The cleaner you eat, the more efficient you’ll be when in the gym or training. A poor diet can not only be attributed to poor performance but can also be a reason that your body is breaking down muscle as an energy source, as I touched on a bit ago.

In today’s world, diets have been overcomplicated to many different “experts,” giving their opinions on what the best possible nutritional path is for an individual. However, at the end of the day, it all starts with a balanced diet, which includes all carbs, proteins, sugars, vitamins, and so forth, but in the right amount.

If you also need another tip for dieting, starting with organic foods is always a huge plus, as cutting out additives and GMO’s will have a huge effect on your diet and how you are performing in the gym. Just keep in mind that healthy eating doesn’t have to cost you a fortune, and it isn’t overly-complicated to follow a good diet.

All it takes is a bit of research and planning out meals, and you will be well on your way to having a successful diet plan that will only improve your fitness performance.


Retired Athlete, Retired Personal Trainer, Retired University Teacher, Retired Sales Manager...

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