How to Do Cardio Without Losing Muscle


Cardio training is well-known for a ton of health benefits, especially for enhancing cardiovascular system and endurance.

However, very few of those who practice fitness and bodybuilding really love cardio. For most, this is just a necessary routine to maintain a low percentage of fat.

At the same time, if you do cardio training the wrong way, chances are you lose muscles very quickly.

How to combine cardio and strength training without stripping away any of your hard-earned muscle?

In this post, I will tell you how you can do cardio without losing muscle. 

The Undoubted Benefit of Cardio Training for Almost Everybody

Cardio is a workout that strengthens the cardiovascular system and endurance. It can be performed both inside and outdoor. Examples of cardio workouts are walking, running, cycling, swimming, etc.

Now, who doesn’t want to have a strong heart and an enhanced endurance? Cardio training brings a lot of benefits to every one of us, regardless of the level of our body condition and health state. 


How to Do Cardio Without Losing Muscle


Important Note: When I say “cardio” in this article, I mean continuous training for up to 60 minutes. A 10-minute run before or after a strength training is a warm-up and hitch, respectively, and not a full-fledged cardio workout.

Thus, if you are wondering whether it is possible and most importantly, beneficial for you to run 10 minutes before or after the strength training, the answer is: yes, it is possible and even necessary.

Next, I will be focusing on lengthy cardio training and how to combine it correctly with strength training.

Cardio Training for Bodybuilders

The fear of losing muscle determines many bodybuilders to be scared and confused about what type of cardio workout to do, when to do it, how long to do it, along with many other concerns. 

If you want to combine your strength training with a cardio workout, there are several options you can go into:

a) Cardio On Weight Training Days;

Here you do a cardio workout on the same day you perform your strength training, but separately from the strength workout (with a minimum interval of 6 hours, in the morning or in the evening). 

If you want to increase or maintain muscle mass, I do not recommend you to perform cardio workout before your main strength training.

I want to emphasize here again that here I mean a lengthy cardio workout of 40-60 minutes; and not a 10 minutes warm-up on a treadmill – this you can do before your main strength training.


How to Do Cardio Without Losing Muscle


Strength training requires a lot of energy and if you do a full cardio workout before your strength training, it will not allow you to train at full strength.

This was proven by studies that show more weight gain in those people who didn’t do a full cardio training before their main strength workout.

If you are afraid of losing muscle, I also don’t recommend you to perform your cardio training immediately after the strength training.

Every day trainings take away the energy that is needed for growth and full recovery of muscles. This is especially true for ectomorphs.

If your goal is to have a harmoniously developed muscular body with minimum fat, then you can do a full cardio workout after your strength training, of course, if you still have enough energy for it.

But what is most important here is the intensity of the cardio workout. Usually, the glycogen stores hit their minimum level after the strength training is finished. 

That is why it is best to perform a low to moderate intensity cardio workout on weight training days.

Thus, the main source of energy for the cardio workout will be fat and not glycogen from your muscles, which will allow you to burn more fat, at the same time preserving so much desired muscles.

It is better to perform high-intensity cardio training separately from the strength training, whether with a minimum 6 hours interval or on the other day, for the sake of muscle preserving. 

b) Cardio On Non-Weight Training Days 

Here is when you actually combine cardio training with your strength workouts, alternating them one day after another. 

As mentioned above, you can do high-intensity cardio training on those days when you are not pushing hard at the gym. 


How to Do Cardio Without Losing Muscle


Let me tell you that there are two main types of high-intensity cardio: continuous and interval training.

1. Continuous High-Intensity Cardio

An example of continuous high-intensity cardio training would be running at a high speed on the treadmill or elliptical machine for a long duration (for example, more than 5 minutes).

2. High-Intensity Interval Cardio training involves alternating periods of work and rest (or lower levels of work).

For example, running a 100-meter sprint then walking back to the start, resting, and then repeating the same path, could constitute high-intensity interval training (HIIT).

Obviously, HIIT is more intense than high-intensity continuous cardio and much more intense than low-intensity cardio.

Does Cardio Workout Help Muscle Growth?

Strength training, excess of calories, as well as adequate time for rest and recovery between training sessions are the most important things for muscle growth.

That is why cardio workout may seem to be not so much important for this particular goal. This is especially true for ectomorphs and mesomorphs.  

If you are an endomorph, and your goal is to maintain a low-fat level, then you want to do plenty of cardio workouts, ideally 3-4 times per week, alternating low-intensity (30-45 minutes duration, 65-75% heart rate) and high-intensity (20 minutes, 75-90% heart rate) cardio workouts. 


How to Do Cardio Without Losing Muscle


I know it may seem like a lot, especially if you want to focus on the strength training, too and finding the time for both could be challenging. That is why it is good to find a compromise.

All you want to do is to determine your main goal: if it is muscle growth, then necessarily do at least 3 strength training per week, and if you can, do cardio on non-weight days.

If you have enough space at your home, you can buy a treadmill, a stationary bike or an elliptical trainer.

Of course, these are additional costs, but you will save a lot of your time, not having to go back and forth to your gym club. Remember it is important not to mix up strength and cardio workouts on the same day. 

Cardio Workout and Nutrition

If you eat a whole bunch of foods, (especially the “empty food”), performing even tons of cardio workouts will not do you any favor. It is always easier to eat 100 calories than to burn them.

On the contrary, if you train a lot, but forget to eat, there obviously will be no muscle growth. Your menu should consist of the “right food” – complete proteins, healthy fats, and slow carbohydrates.

It is not always easy to gain the needed amount of calories through the “right food” intake. 


How to Do Cardio Without Losing Muscle


If you do HIIT, then feel free to include in your menu a protein-carbohydrate snack 30-60 minutes before the workout.

During HIIT, our body receives energy the same way as it does during the strength training – from carbohydrates.

This happens because there is a need for a lot of energy at once, and it takes time to get it from the fat stores.

So, the most rapid way is to get it from carbs. The purpose of HIIT is not to burn the maximum amount of calories, but to start up metabolism for the whole day, which will allow burning more calories later on, even if you just sit and do nothing.

Here is where HIIT is very much similar to the strength training. That is why I don’t recommend you to complete this kind of trainings on an empty stomach.

Also, please note that a snack should be considered as a bonus to the daily food intake. This is just one of the scheduled food intakes, a part of daily caloric intake. After you have finished your training, you can drink a protein cocktail with a protein and carbohydrates ratio of 1:2.

Cardio Workout on an Empty Stomach – To Be or Not to Be?

I think you are aware of the fitness practice known as “cardio workout on an empty stomach”. Maybe, you have already tried to work out in this way?

Well, then, most probably, you know that there is no common opinion about it yet.

The supporters of this method claim that our body uses first and foremost fat as an energy source. In other words, you don’t need to eat carbs before your cardio workout as they are simply not used.

Now, this doesn’t mean that you shouldn’t consume carbs before the workout. But they are going to be used as an energy source for you throughout the day and not in the time when you do your low-intensity cardio workout. 


How to Do Cardio Without Losing Muscle


On the opposite side, the opponents of doing cardio on an empty stomach use some research that shows the need for carbs as a source of energy for transportation of fats breaking down during the exercise. That is why there is no need to have breakfast before the cardio workout. 

However, as I have mentioned above, there is no common opinion on this subject yet. All you can do is try both and see what is more comfortable for you and what results you get. 

Following YOUR Fitness Goal is Best What You Can Do

Remember, cardio does not just get you lean, it also gets your muscles hard. How much cardio you can do without losing muscle mass is something you will need to experiment with and determine on your own. 

Keep in mind that cardio for bodybuilders is primarily a means of burning fat and increasing the definition that should be done in moderation.

If you was lifting weights for some time but ignored the cardio component, I highly recommend you start performing cardio training regularly, especially if you are an endomorph type of body. 

There is no best or most effective type of cardio workout. I do recommend you to alternate your low-intensity (running or riding a bike) and HIIT training (same running and cycling but with variable speed). 

It is no matter where you train: outside or indoor, the most important thing is to do it consistently while maintaining the needed intensity. For example, during HIIT, apply the maximum effort (90% heart rate), don’t be lazy! 

If you combine cardio and strength training, remember that the best option is to perform low-intensity cardio workout after the strength training, while setting aside a separate day for HIIT. 

To stay motivated, try out different types of cardio. For example, today do low-intensity walking on a treadmill, and the day after tomorrow do HIIT on an elliptical trainer. This change in cardio training types will help make your workouts less boring. 

If you have a possibility, watch your favorite movie during a long cardio session, and for HIIT play your favorite music. These are the most obvious things that you can do, but they work!

Here is a great combination of music that you can listen during the cardio workouts that will keep you motivated:



I hope you have enjoyed reading my article and now you know more about how to do cardio without losing muscle.

If you have any questions or thoughts, or just want to say “Hi!”, please comment below in the discussion area. 

Also, if you find this information useful, please show some love and be kind to share this post with your friends on social media.

My best wishes to you,

Ionut Voicu

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