For people focused on building or maintaining muscle, cardio can sometimes get a bad reputation. There is a common belief that spending too much time running, cycling, or doing other forms of cardiovascular exercise will cause the body to break down muscle and interfere with strength and muscle-building goals. But cardio itself does not automatically lead to muscle loss. In fact, cardiovascular exercise can be an important part of a well-rounded fitness routine. The key is understanding how cardio fits alongside resistance training, nutrition, recovery, and your overall activity level.
Where Does the Concern Come From?
The idea that cardio “kills your gains” usually comes from situations where someone is doing a high amount of endurance exercise while also eating too little, recovering poorly, or not getting enough protein. Muscle maintenance and growth require adequate resources. When training demands are high and nutritional intake or recovery does not keep up, maintaining muscle can become more difficult. That does not mean cardiovascular exercise is inherently responsible. A person can include cardio in their routine while continuing to strength train and support their muscle-building goals. The bigger picture matters.
Resistance Training Still Plays a Major Role
If maintaining or building muscle is a priority, resistance training should remain an important part of the exercise routine. Strength training provides the mechanical stimulus that tells the body that muscle tissue is needed. Consistent resistance training can help support muscle strength and development over time.
Cardio serves a different purpose. Rather than viewing cardio and resistance training as competing forms of exercise, it can be more useful to think of them as addressing different aspects of fitness. Resistance training supports muscular strength and development. Cardiovascular exercise supports cardiovascular fitness and endurance. A balanced routine can make room for both.
Why Cardiovascular Exercise Matters
Cardio isn’t simply something you have to do to burn calories. Regular cardiovascular activity can help improve aerobic fitness and make everyday physical activities feel easier. It can also support heart and lung function and contribute to overall physical fitness. The American Heart Association recommends that adults aim for at least 150 minutes of moderate-intensity aerobic activity per week, or 75 minutes of vigorous-intensity activity, along with muscle-strengthening activity on at least two days per week. You don’t necessarily have to reach those numbers immediately. Your appropriate activity level can depend on your current fitness, schedule, goals, and individual circumstances. The important takeaway is that cardiovascular fitness deserves a place alongside muscular fitness.
What Can Actually Make Muscle Maintenance More Difficult?
If someone is losing muscle while doing a significant amount of cardio, it is worth looking beyond cardio itself. Several factors can influence the body’s ability to maintain muscle, including:
- Insufficient nutrition: Consistently eating too little can make it harder to support training and maintain lean tissue.
- Inadequate protein: Protein provides amino acids needed for muscle tissue maintenance and repair.
- Too much training with too little recovery: Exercise creates a demand for recovery. Constantly increasing training volume without adequate rest can make it harder to perform well.
- Reduced resistance training: If strength training disappears from the routine, the body receives less of the stimulus associated with maintaining muscle.
- Poor sleep: Sleep is an important part of physical recovery and overall health.
- Rapid weight loss: Losing weight very quickly can increase the challenge of preserving lean mass, particularly when combined with inadequate protein and resistance training.
In other words, the context surrounding cardio matters.
You Can Train for Your Heart and Your Muscles
You don’t necessarily have to choose between cardiovascular fitness and muscular fitness. A well-designed routine can include both. For example, someone might perform resistance training several days per week while incorporating walking, cycling, or another form of cardio on separate days or after selected strength-training sessions.
The exact approach will depend on the individual’s goals and schedule. Someone training specifically for a long-distance endurance event will naturally have very different cardiovascular demands from someone whose primary goal is strength or muscle development. That is why exercise should be approached individually rather than relying on one-size-fits-all rules.
One of the biggest problems with the idea that “cardio kills gains” is that it can encourage people to avoid cardiovascular activity altogether. Building muscle is valuable, but cardiovascular fitness is valuable too. Your body isn’t divided into completely separate systems where improving one automatically means sacrificing another. Strength, endurance, mobility, recovery, nutrition, and daily movement can all contribute to a broader picture of physical fitness. The objective should be to build a routine that supports your overall health while aligning with your personal goals.
Final Thoughts
Cardio does not automatically cause muscle loss. Muscle maintenance is influenced by the combination of resistance training, nutrition, protein intake, recovery, sleep, overall training volume, and energy balance. For many people, cardiovascular exercise can comfortably coexist with a muscle-focused training program. So instead of asking, “Will cardio kill my gains?”, a better question may be: “How can I include cardiovascular exercise in a routine that supports my overall goals?”
The answer will look different for everyone. At Stracuzzi Wellness, we believe health and fitness should be approached as a complete picture rather than through isolated rules or trends. Understanding your goals, lifestyle, nutrition, activity, and overall health can help you build a more individualized approach to wellness. For a more personalized advice, reach out to us. Our goal is to help you look better, feel better and perform better. Get started today!
