In the past, getting in shape meant putting on a pair of trainers and going for a run. But these days, people who want to get in shape are more likely to be told to try lifting weights.
In fact, cardio has become a somewhat maligned form of exercise in some circles, with much debate about it online. Not only are people wondering if you should do cardio during the same workout you lift weights, some even argue that you shouldn’t do it at all (lest you ruin those hard-earned “gains”).
The answer to this question is not entirely straightforward and depends on your fitness level and your goals.
The interference effect
Most of us do at least a little cardio to warm up before a workout – preferring to save dedicated cardio sessions for another day. But others prefer to combine resistance training (like weightlifting) with cardio training in the same session. This is known in the scientific literature as “concurrent training”.
When concurrent training was first studied in the 1980s, research concluded that it resulted in fewer strength gains compared to resistance training alone. This has been called the “interference effect”, which suggests that simultaneous training interferes with our ability to build both strength and endurance. But more recently, the view on the interference effect has changed – with research showing it’s more nuanced than it first appeared.
In 2012, a meta-analysis of all previously published studies on the interference effect was performed. He suggested that simultaneous training actually resulted in lower strength gains and less muscle growth, as well as reduced improvement in power (such as the explosive strength needed to sprint or jump) compared to training in resistance alone. For many people, this confirmed their long held belief that simultaneous training is bad for those who want to build muscle and strength.
But there were several problems with the way this analysis was conducted. For example, the researchers did not take into account differences in participants’ fitness levels. They also compared studies where participants performed cardio and weights during the same workout with those who performed each activity during different workouts (sometimes even on different days), which may not not accurately show the real effect of simultaneous training.
Since then, research has actually shown that for the average person, doing cardio and weightlifting in the same workout has no significant effect on strength versus cardio and weightlifting in separate workouts. Another study confirmed that the interference effect does not affect strength and gaining muscle mass. However, it can impact power, especially explosive strength.

These results appear to be true whether cardio is performed before or after resistance training – although it appears the type of cardio may play a small role, with run more likely to cause an interference effect than other forms of cardio like cycling.
What should you do?
Generally, people new to exercise benefit from the addition of cardio to a resistance training routine. Although it is not essential that they are performed in the same session, many people find that combining their training is a faster way to meet the needs. World Health Organization guidelines 150 minutes of moderate-intensity exercise (or 75 minutes vigorous) per week.
For more advanced lifters, whether or not to train weights and cardio in the same session depends on your goals. For example, a competitive bodybuilder may not want to risk any chance of stunting his progress. Other athletes focused on training power and explosiveness may also want separate their workouts to avoid any potential negative effects.
As for whether you should give up cardio altogether, the answer to that question also depends on your goals. Certain types of strength training (such as “training to failure”, where you perform an exercise until your muscles are temporarily so tired that you can’t perform the movement) can improve cardiovascular fitness.
But specific cardio training can confer different benefits, such as allowing our blood to pump more blood around our body with each heartbeat and improving our oxygen-carrying capacity. This means that cardio workouts help our heart do its job better, improve our performance and reduce our risk of heart disease. heart disease. The good news is that these cardio benefits occur even with concurrent training.
Of course, many other factors can influence how you structure your training, such as how much time you have and whether you like certain types of training. For most of us, the interference effect will be mostly insignificant – so whether you do cardio before or after a workout (or not at all) is a matter of personal preference. In reality, the best workout is the one you do regularly.