Does cardio kill gains? Many of my clients are interested in building muscle or improving their body composition by improving their ratio of muscle to body fat. They want to build the most muscle possible, but also improve their cardiovascular fitness and health. Can they incorporate cardio into their routine, or will that take away from the muscle building stimulus of the strength training program? Will cardio kill their gains? In this post, we will answer that question.
The Interference Effect
In 1980, Hickson et. al conducted one of the first research studies on concurrent training–that is, a training program that incorporates both strength and cardiovascular training. In his study, he found that test subjects that performed both resistance and cardio training in one program gained less strength and muscle mass than subjects who just performed strength training.
He interpreted his study as evidence that performing aerobic training concurrently with resistance training could attenuate the results of a resistance training program.
For many years, those people interested in powerlifting, body building or just building the most muscular physique possible took the results of this study as their sign not to include cardio training in their program.
However, there were many limitations to Hickson’s study and research findings that we will discuss in more detail below.
Limitations of the Study
Hickson’s research participants doing concurrent training might not have experienced much of an interference effect after all. As later critics of the study have pointed out, the concurrent training program was quite extreme–including six weekly aerobic training sessions at VO2 max and five strength training sessions to failure. It’s possible that the subjects were just facing an overtraining effect rather than an interference effect.
Additionally, the subjects only completed the study for a short time period. So it’s possible that in the long term, strength trainees who include some cardio gain more strength in the long term. According to one study, subjects who performed concurrent training did not gain less muscle strength or muscle endurance than those who just did strength training. Strength trainees who perform cardio training in addition to strength training have been shown in some studies to experience increased muscular strength and endurance, as well as improved cardiovascular fitness, metabolic benefits and health benefits.
In order to incorporate cardio into your resistance training routine without compromising your muscle or strength, you should follow a few key tips.
Cardio Volume
In order to prioritize muscle strength and growth while still getting most of the benefits of cardio training, avoid large volumes of exhausting cardio. While running marathons or ultra marathons might not be optimal from a muscle building perspective, two or three twenty to forty minute low to moderate cardio sessions per week can help boost endurance and heart health without killing your gains.
These cardio sessions can be low to moderate intensity. Try to keep your heart rate from roughly 60 to 70 percent of your heart rate max.
Best Modes of Cardio to Preserve Muscle
The mode of cardio that you use also matters. Low impact forms of cardio like walking, low intensity cycling, swimming and using an elliptical are all great forms of cardio that won’t fatigue your legs too much. In contrast, heavy cycling or running might fatigue your legs and compromise your next leg day.
When to Perform Cardio
Speaking of leg day, try to program your cardio after your weight training sessions so that you do not compromise your strength. Performing interval or steady state cardio after your leg day can help you consolidate stressors and avoid compromising your strength on leg day.
If you participate in a sport that requires explosive strength (team sports, gymnastics, Olympic weightlifting) you might even want to perform your strength and cardio in separate sessions to minimize any interference effect.
Finally, make sure you consume adequate calories and protein to avoid muscle protein breakdown. To keep as much muscle and strength as possible, you also shouldn’t perform fasted cardio.
Final Thoughts
Fortunately, cardio doesn’t have to kill your gains. If you want to have great endurance and heart health while also getting strong and jacked, you can do it by monitoring your overall cardio volume and intensity, performing cardio at the right times and eating and recovering properly.
If you have any specific questions about how to do cardio without killing your gains or you want to work with me to design a training program, you can reach me here.
