Does Cardio Kill Gains? The Truth Behind the Heart-Pumping Routine

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Does cardio kill gains? You’re not the first reader to ever ask this question. Almost every bodybuilder and workout buffs worry that cardio routines will make them a lightweight. It’s a big question that’s often misexplained. But the truth is, Cardio won’t kill gains as long as you do it right.

Cardio strengthens your heart and lungs while weights rip your muscle. You need strong lungs to do weights. Now, you’re getting the picture. Before diving into details, we also have a detailed analysis on the best cardio machine for abs , do check out if you are looking in particular for abs.

What is cardio, in the first place?

When we talk about cardio routines, most people will think about running or jogging. The truth is that cardio is any routine that increases your heart rate. Yes, running counts, but it can also be jumping rope, aerobics, vertical jacks, and even sex.

It’s also true that cardio breaks down and uses stored energy. It may sound counterintuitive if you’re aiming to beef up. Still, cardio has a lot of benefits:

  • It keeps your heart and lungs strong
  • It’s a nice way to sweat
  • An excellent recovery workout choice
  • It’s great in clearing out wastes and metabolites
  • Decreased risk of diabetes
  • Increased recovery abilities

Still, there are some disadvantages too, especially if you don’t use cardio routines right. Lifters should be aware of the following:

  • It’s a tool for weight loss
  • You may lose muscle mass if you focus on it too much

Types of cardio


Steady-state cardio is the routines that pop to our minds when we hear the word “cardio.” It includes biking, running, swimming, aerobics, and so on. These routines increase your heart rate. It will reach a certain level where it will stabilize, allowing you to perform the activity for an extended period.

High-Intensity Interval Training (HIIT)

HIIT routines, on the other hand, are the activities that increase your heart rate then decrease it. This will be done in multiple reps in between short recovery periods. The on-and-off process of HIIT is ideal for weight loss, thus, not the perfect choice for heavy lifters who want to gain mass.

HIIT workout for woman

So is cardio purely evil?

If you’re a lifter and you decided to focus on running, you’ll definitely kill your gains. The key here is combining both routines to maintain muscles or even gain more mass.

To know how cardio affects your mass, we have to understand how it consumes fuel from the body.

First of all, you need a caloric surplus to build muscles. However, cardio exercise tends to burn these calories. This made newbies think that cardio will kill their gains right away.

Still, you have to know that our bodies have three main energy systems, namely ATP-PCr, glycolytic, and aerobic. All of these produce ATP, the most basic form of energy that our body uses to sustain its operation.

The ATP-PCr system is the fastest to produce energy, but it can only do so at a maximum of 10 seconds each time. Also, it will take more time to recover before it can produce more energy.

Meanwhile, the glycolytic system is just like the ATP-PCr, but it can sustain energy production for 120 seconds.

Lastly, the aerobic system is the one that’s always up and running. Although it takes longer to ignite, it will keep running for hours once you get it going.

Utilizing your aerobic system will help you crank up an endless supply of ATP, which will support your exercise. It will also help keep your heart and lungs in check without killing your gains.

Steady-state cardio is the way to go

Steady-state cardio like aerobics also helps in clearing metabolites and wastes that affect your performance. Also, the combination of resistance training and aerobic exercise is unmatched when it comes to improving your body composition.

The aerobic exercise decreases your hunger levels while resistance training boosts your metabolic rate. As your body improves its composition, you will have better insulin sensitivity and higher levels of leptin, which helps balance energy and regulate hunger.

Aside from that, it’s proven that enough cardio will increase your recovery phase, which is critical with resistance training. Also, since you’re not supposed to do resistance training every day, cardio becomes your resort to keep your body systems going.

Cardio and muscle recovery

When you strength train, your muscles sustain tiny tears, which explains the soreness after the workout. These tears need to recover and this will only happen at rest. Aside from patching up the torn muscles, your system will build thicker and more muscle tissues. This is how you gain mass.

When at rest, many buffs fear that doing cardio will kill their gains. Since muscle building needs energy, it makes sense why many have this worry.

Still, if you do it right, you can avoid the adverse effects of cardio exercises. In fact, you can use cardio to speed up your recovery. As your heart rate increases, blood flow also escalates, which improves the oxygen and nutrient flow to the sore muscles.

Take note that your muscles produce lactic acid when it gets deprived of oxygen. The more lactic acid buildup, the more muscle fatigue you’ll experience. Recovery would be slow and the muscle damage will pile up if you go back to training without fully recovering from your previous workout. 

Cardio exercises help flush out lactic acid while maintaining your energy levels. This will prepare you for your next resistance training.

When does cardio become detrimental to muscle mass?

Too much of anything is bad, and that includes cardio exercises. Excessive cardio will eat up much of your body’s caloric surplus. If you don’t eat enough to cover the caloric usage of your cardio routines, you may start to lose mass or experience plateaus with your workout results.

Aside from that, too much cardio will tire your body to the point that you’re too weak to lift. If you’re planning to incorporate a steady-state cardio routine to your training program, always keep it in a low intensity.

Also, you’ll lose muscles if you perform intense cardio during your lifting days. You’re subjecting your body to two energy-hungry activities. When this happens, you’re going to burn more calories than what you should be to gain mass.

If you use cardio right, it can be your tool to break plateaus. Still, you should always watch out for the tipping point to avoid leaning toward muscle loss.

Don’t demonize cardio

It’s easy to be swayed on what newbie muscle buffs say. Also, a lot of TV celebrities give false information that leads to misconceptions, cardio killing gains, for example.

Doing cardio once or twice a week should be enough for your recovery from training days. Exceeding that amount will lead to fat loss and weak body composition.

What you need to know about cardio hypertrophy

Hypertrophy is defined as muscle building. And yes, there’s a thing called ‘cardio hypertrophy.’ This refers to the enlargement of the heart muscle and not general muscle gain per se.

Cardio routines work the heart muscles, which causes it to become stronger and larger. This makes you more enduring when performing heavy exercises.

Still, too much cardio hypertrophy may abnormally enlarge the heart. This can lead to stroke and even heart attack. Just like in lifting weights, you need to set a limit.

Aside from preventing muscle loss, excessive cardio hypertrophy is another reason why you should keep cardio at a minimum.

How to do cardio without losing muscles

You can continue doing cardio without negatively affecting your muscle gains. You just have to be cautious with some details to make sure that it’s not burning hard-earned mass.

It’s all about the impact

The more impact the cardio does to your body, the more muscles you’re likely to lose. The common problem is that heavy lifters tend to give their all during the exercise. But when it comes to cardio, they need to tone it down.

The rule of thumb is to stay within 65% to 80% of your maximum heart rate. This is possible, again, by introducing aerobic routines to your program. Steady-state cardio lets you control your heart rate while limiting its impact to your body.

You can try swimming, biking, rowing, or Zumba. These are low-impact but very effective in promoting recovery without taxing your body too much.

Watch the amount

Aside from controlling the intensity, you should also monitor the amount of cardio that you do. Studies showed that performing cardio for three days or less, and under 50 minutes per session will not impact muscle gains a lot.

Going beyond that amount will make your body too weak to sustain the time under tension when lifting weights. To be sure, keep your cardio sessions at a maximum of 30 minutes in 3 sessions per week. You can do less if you’re prone to muscle loss.

As much as you want to push yourself to the limit, overdoing your exercise is never healthy. Remember, when it comes to cardio, less is more.

Timing is everything

Aside from setting the right amount and controlling your heart rate, you should also perform cardio during your off days from resistance training. This way, you will spare your muscles from too much fatigue.

Always perform cardio as far away from your strength training as possible. If you need to do cardio during your lifting day, make sure that you separate the two routines between hours. You can do cardio in the morning then lifting in the evening. This will buy your muscles some time to recover and regain its strength for a more strenuous exercise.

The best gap between cardio and lifting is at least 12 hours if you can’t manage to perform it in different days.

Another option is to perform cardio after lifting weights. Observe a minimum of 6-hour gap before you subject your muscles to another form of exercise.

Eat right

A critical component of maintaining your muscle mass is by eating based on your goals. The main reason why you lose muscles when lifting and doing cardio is that your body doesn’t have enough calories to sustain the two activities.

You need to supply your body with enough protein and calories to prevent muscle breakdown. The rule of thumb is to consume around one gram of protein for every pound of your body weight. This should be sufficient to maintain your lean muscle mass.

Serious lifters take more than one gram per pound of their body weight together with hefty calories. To know how much calories you should consume, you need to gauge the following factors:

Activity level: how much cardio and lifting are you doing?

  • Inactive – You don’t exercise at all
  • Lightly active – You perform 30 to 60 minutes of all-out intensity exercise 1 to 2 times a week.
  • Moderately active – You perform exercise routines 3 to 4 times a week
  • Highly active – You exercise 5 times a week and in high intensity

You can consult a nutrition expert to calculate your caloric needs accurately. Although it’s convenient to chomp protein powders, make sure that it’s not taxing your kidney and liver too much.

Remember, you need a caloric surplus to prevent muscle loss. Poor fueling is one of the leading causes of muscle loss among lifters. 

When your body no longer has any excess energy, it will start to break down protein and amino acids. These are the main components of your muscles.

Also, you shouldn’t shy away from carbohydrates. These are packed with calories that you need to bulk up. The International Society Sports Nutrition recommends 5 to 12 grams of carbs for every kilogram of body weight. The higher your workout intensity is the more carbs you’ll need.

Be consistent with your workout

Sometimes, it’s not cardio that sabotages your muscles but your inconsistent workout schedules. To make sure that you’re not going beyond your ideal limit, come up with a schedule and stick to it.

Aside from defining your workout hours, you should also schedule the days on which you’re going to lift, or you’re going to cardio. Like what we mentioned earlier, timing is crucial if you want cardio and resistance training to co-exist.

How much cardio is too much cardio?

Again, as we said earlier, 30 minutes should be safe for your muscles. If you happen to experience these four issues, you’re likely doing more than what’s ideal:

Short-term muscle fatigue

If your muscles feel tired from all the cardio you’ve done, you probably did too much. This will hinder your lifting efficiency and your muscles will become sorer if you push it with excessive resistance.

Total exhaustion

Total exhaustion is when you feel you’re going to konk out after doing cardio. Any efforts of lifting weights will be in vain. Aside from that, you will overexert your muscles. This will lead to muscle loss or a longer recovery time.

Motion injuries

When you lift weights and do cardio within a short time frame, motion injuries will soon accumulate. It’s not the cardio routine but the improper combination with resistance training. Soon enough, these motion injuries will take its toll on your muscles. Since your body aches, it will be impossible for you to lift weights without feeling pain. If this lingers, you will slowly lose muscles from failing to exercise.


This one’s the worst. When you over train, you will lose both muscle strength and mass. It will also lead to total exhaustion. In the end, you will have to wait for recovery for weeks, if not months.

Practical ways to combine cardio and weight training

A little bit of cardio and a lot of lifting is the basic formula to gain muscles. If you happen to hit a plateau or decrease in mass gains, you can reduce your cardio and see if you get back on track. Most of the time, it does the trick.

Also, it’s best to spread the cardio routines on your body. On the first week, you can run, on the other you go swimming, and the next you do the rowing. This way, you don’t just exhaust a specific muscle area on your body while doing cardio. The same goes when you’re lifting weights.

Here’s a simple guide that you can use to incorporate steady-state cardio on your strength training program:

Monday: Lower-body weight training

Tuesday: Upper-body weight training

Wednesday: 30-minute steady-state cardio

Thursday: Upper-body weight training

Friday: Lower-body weight training

Saturday: 30-minute steady-state cardio

Sunday: Total workout rest

This is just a simple schedule that you can follow to ensure that cardio is spread all over the week. You’re also free to alternate the cardio days to weight training days. You can also free up another day for resting and recovery.

Does Cardio Kill Gains? – Our Verdict

So, does cardio kill gains? If you do it right, it should help you gain more mass and maintain your excellent body composition. Cardio routines keep your heart and lungs strong while aiding your recovery. Just make sure that you follow the right amount, intensity, and timing to make the most out of it.

Do you have questions about gaining mass? Let us know below in the comment section!

Does Cardio Kill Gains? The Truth Behind the Heart-Pumping Routine
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Does Cardio Kill Gains? The Truth Behind the Heart-Pumping Routine
This article provides detailed insight about cardio and how to use it along with answers to common questions
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