Cardio workouts are one of the most beneficial things you can do for your health. Science shows that a cardio workout has many positive health effects beyond weight loss, including improved cholesterol, reduced risk for diabetes, lower resting blood pressure, higher-quality sleep, better mood, and enhanced brain function. Another benefit of cardio is that it builds muscle strength.

Many bodybuilders and other weightlifting aficionados believe the opposite is true, that cardio workouts destroy muscle gains. Cardio workouts and strength training indeed condition the body in basically opposite ways, but people who completely abstain from cardio when they’re trying to build muscle mass are taking it too far and most likely missing out on more muscle gains. 

It can be difficult to digest all the information available about cardio and aerobic exercise and its effects on skeletal muscle growth. This article is for anyone who wants to know how much cardio they can fit into a weight training program and still build muscle. We’ve also included some high-intensity interval training (HIIT) recommendations to fit cardio into a fitness routine without the use of a treadmill. Read on for the full rundown.

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Strength Gains & Muscle Hypertrophy

Muscle hypertrophy is the scientific term for the growth of existing cells. The most common type of muscle hypertrophy is the growth of muscle tissue as a result of resistance exercise. However, there is also muscle growth called pathological hypertrophy that is not positive. It typically occurs in muscles like the heart that we don’t want to see grow.

Healthy muscle hypertrophy is the result of muscle damage. The exact cause of muscle damage isn’t well understood because it happens in a variety of circumstances that are unlike one another. For example, muscle damage can occur when muscles are lengthening under heavy strain or it can happen when muscles are contracting. 

Lifters typically build muscle following muscle damage. The body sends additional resources to the injured muscles so that they can better handle strain in the future, resulting in strength gains and muscle gains. Cardio seems to benefit this process when done 2 – 3 times a week at moderate intensity. 

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Running is one of the best cardio exercises for burning calories.

Benefits of Cardio Training

Cardio training can lead to weight loss in both men and women all by itself, but that’s not all it’s good for. Many people only see cardio as an avenue to fat loss although it can also help regulate blood pressure, slow the resting heart rate, and reduce the risk of diseases such as diabetes. Some studies even show that aerobic exercise can be used to prevent muscle loss in older people. 

For folks concerned more with muscle gains, though, moderate-intensity aerobic workouts a few times a week can help get rid of body fat and make muscles more visible. It can also help maintain muscles and help develop the muscles in the lower body in addition to offering the health benefits already mentioned. 

Best Aerobic Exercises for Weightlifters

So, if people predominantly concerned with muscle gains can still benefit from some cardio, what cardio should they be doing? There are so many types of aerobic exercises and finding the right one will depend on what kind of weight training you’re using to build muscle. Generally, though, there are a few you should consider adding to your training regimen 2 to 4 times per week.

High-Intensity Interval Training (HIIT)

HIIT exercises are one of the best ways to work out all your body’s muscle groups and build athletic performance. Many weightlifters may have impressively large muscles but fail to develop them to do anything besides lift weights. For the best balance between athletic performance and sculpted muscle, HIIT is where it’s at. 

They may not seem as difficult as power cleans or other strength training exercises, but HIIT will wind you. Give burpees, plyometrics, or mountain climbers a try and see how long you can go. Just remember, if gains are your main goal, then you won’t want to do plyometrics or HIIT more than 2 or 3 times a week. 

Even without strength training with weights, people should only perform high-intensity exercises like these a few times a week. Rest days are critical to allow the body to rebuild muscle since that’s how you get strength gains. 

Sprints & Stadiums

We already mentioned how resistance exercises and endurance training condition the body in opposing ways. That’s why sprints and short-burst cardio like sprints are better for weightlifters than steady-state cardio like long-distance running. 

Quick-burst running exercises help improve your body’s recovery time and energy regulation, which will help when you get back to the weight room. Running long-distance can negatively affect muscle size, but sprinting doesn’t force the body into an endurance situation for long periods and won’t have the same detrimental effect. 

If you have a place available where stadiums are possible, or even a hill to run up, that will be much better fast cardio than sprinting on flat land. It will help boost lung function and give you a definite course to follow on your cardio days. If it’s a steep enough path, you can probably get away with 2 or 3 sprint sessions per week.


Just like running, as long as you avoid long sessions that start to activate your body’s endurance faculties, swimming is a great way to get some cardio without risking muscle gains. It’s a low-impact exercise and it works your upper body and lower body at the same time. It’s a great way to get cardio while still letting muscles heal after a weightlifting session. Plus, it’s nice to have something completely different from the weight room. 

Some myths about the effects of swimming on a weightlifting routine are based in fact. For instance, there are some strokes like the freestyle that can potentially injure your shoulders if you use the wrong form, swim too long, or aren’t used to the movement. Exerting yourself too much when you swim could also increase your appetite and cause you to risk your gains to body fat. 

That being said, if you swim in the right way it can make a great compliment to the weight room exercises that form your weightlifting plan. If you don’t overdo it, you can use some swimming stroked to boost the range of motion in your shoulders. Swimming also works other rotational muscles and it’s a great way to stay active while you deload. 

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That’s right, walking can be a great way to get some cardio benefits. It’s a low-impact exercise that you can fit into a busy schedule. Weightlifters would do well to try and follow the 10,000-step walking plan. Once you get used to walking more, you’ll be able to fit in all those steps without even noticing. 

Walking is a much less intense way to keep your heart rate up outside the weight room. Burn a few hundred extra calories walking to make your muscles stand out. You won’t risk overworking your body like you possibly can with HIIT or other physically demanding exercises. 

One of the best ways to work on your body’s endurance without having it affect your muscle fibers. Unlike running, which can affect body composition if you do it for long stretches, walking is a form of active recovery that you can enjoy for long periods with little risk of muscle loss. 

What Amount of Cardio is Best for Strength Training?

Although cardio can help as active recovery on rest days spent out od the weight room, doing too much cardio will wreck your muscle gains. There’s a sweet spot where you’ll get all benefits and no muscle loss. Finding that sweet spot will take some time because each person’s body responds to outside stress differently. 

Most weightlifters fit some kind of moderate-intensity cardio in on their rest days two or three times a week. If you want to change things up a little and use swimming or HIIT as cardio workouts to compliment your weight training routine, you can probably do one day of swimming, one of HIIT, and another of sprints if you want to add a third day. 

You shouldn’t spend hours on cardio workouts, either. 40 minutes to an hour is just about all it takes to get the benefits of cardio without risking muscle loss. If you’re going walking on rest days to get some cardio outside the weight room, you can go for anywhere from 2 to 6 hours per day. The more briskly you walk, the less time you should spend walking. That’s what makes the 10,000 step plan so effective for weightlifters: it’s a form of active recovery that won’t engage your endurance muscles so much that it will risk muscle loss. 

Using Cardio to Boost Energy Levels

Bodybuilding takes a lot of effort and there are very few ways of improving your body’s energy distribution than some high-intensity cardio. Adults who don’t engage in strength training took as little as 20 minutes of cardio to see improved energy levels according to one study from the University of Georgia. Even low-intensity exercises reduced fatigue symptoms for the study participants.

Of course, it’s different for people trying to build muscle with strength training. Low-intensity cardio is the last thing you want to be doing for long periods unless it’s brisk walking. To boost your energy levels, use active recovery exercises we already mentioned like swimming or sprints. You’ll naturally feel tired afterward, but over time your body will become accustomed to the fast cardio and you’ll find your energy levels have risen for activities across the board. 

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Concurrent Training and Bodybuilding

What’s the best way to mix resistance training and endurance training? For the best effects on a bodybuilding routine, you need to design a plan that has enough rest days for your muscles to recover and make sure not to overtrain your body or steer it in the wrong direction with too much endurance training. 

If muscle gains are your number one priority, then occasional or even irregular cardio is probably fine. But to get the best results on your body’s overall performance and not just the way it looks, you should be doing 3 days of cardio, preferably on days when you don’t visit the weight room. 

It used to be common knowledge that cardio kills muscle gains, but people are coming around to the idea of concurrent training more and more these days. Concurrent training improves flexibility in the neck and shoulders and it will improve your performance in long-term endurance actions. 

Cardio can be a part of everyone’s workout routine without killing gains.

Nutrition and Concurrent Training

Balancing macros and calorie expenditures to maximize muscle gains is challenging enough. The good news is that moderate-intensity cardio isn’t going to skew your diet enough for ou to have to make any major changes. If anything, it will give you a little more wiggle room since you’ll be burning a bit more fat on your rest days. You must have enough energy sources to keep your body from consuming muscle mass for energy. As long as you can manage to stay above 5% body fat, you shouldn’t have to worry. 

Protein is a cornerstone of any good nutrition strategy that pairs well with concurrent training. Consuming enough clean protein from skinless white meat like chicken or fish, or vegan alternatives like chickpeas and other legumes is the best way to prepare your body for bodybuilding and moderate-intensity cardio on rest days. 

Don’t cut out carbs completely, either. They’re our bodies’ go-to source of energy and very important to have around to ensure your body doesn’t undergo any endurance adaptations that lead to muscle loss. When balanced out with other important macros, carbs play an essential role in bodybuilding. 


Many people who are trying to build muscle completely ignore cardio in favor of training sessions that concentrate solely on weightlifting. Many people incorrectly believe that cardio kills muscle gains and must be avoided, sometimes to the point of avoiding any kind of cardio altogether. However, the latest research has shown that incorporating some degree of moderate-intensity cardio into a strength training plan not only won’t destroy muscle gains but even help build and preserve them. 

Your body will consume muscle mass if it has nowhere else to turn for energy. That will only happen if the level of body fat is extremely low, between 3 and 5 percent, which is not the case for the vast majority of people. It also takes a long, high-intensity round of cardio to consume enough energy to result in muscle loss. The people most likely to see some muscle loss after a cardio workout are marathons runners and others who run more than 1 hour 5 or more days per week. 

The unfortunate part about the cardio-kill-gains myth is that including the right amount of low to moderate intensity cardio in your training program can help with building muscle. Provided it’s done on different days than your strength training, some cardio can help promote muscle growth. This is contrary to what most weight training enthusiasts believe, but it’s supported by the latest research. 

That doesn’t mean you should do cardio before your workout days or that you have to include cardio sessions if you want to build muscle. But since cardio has such a positive effect on overall health, it’s worth understanding how much of it you can do without interfering with a strength training program. 

Resistance training, which is the kind of exercise we do to build muscle, relies on different functions than endurance training, which is the kind of exercise marathon runners and most athletes do. You can tell from the condition of most soccer players that they aren’t concentrated on their upper body and their exercise routine involves lots of cardio. Many football players, however, have to mix both cardio and strength training to be effective on the field. 

When it comes to endurance training, it’s all about the intensity, frequency, and type of cardio. Some cardio can boost muscle hypertrophy when done the right way one or two times a week. Other cardio exercises can exhaust your muscles, making weightlifting exercises either impossible or less effective. There’s a tradeoff between resistance training and endurance training, but that doesn’t mean you should completely drop cardio from your schedule when you want to gain muscle. 

Strength gains aren’t a large part of many bodybuilding plans. Leaving out cardio can create a sculpted muscular body frame that’s incapable of exerting itself for very long, which is a constant embarrassment for weightlifters who have trained improperly. Building a bodybuilding routine with 2 or 3 days of cardio on rest days is the best way to make muscle and strength gains that will last. Far from destroying your muscle gains, cardio will help improve your endurance and overall bodily function.

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