Doing Cardio Before Weight Lifting May Help Boost Muscle Gains

Ever wonder if it's a good idea to mix cardio and strength training exercises or if they should remain separate entirely? Well, there's interesting research to suggest that doing cardio before you lift weights can actually help you build more muscle.

The study, which was published in the journal Scientific Reports, had eight men do two different exercise sessions. In one, they did an intense 20-minute interval cycling workout, followed by upper body resistance exercises, which included 10 sets of heavy resistance on an arm extension machine. In the other, the same group of men just focused on doing the same strenuous upper body resistance exercises without the cardio beforehand.

The study's researchers took blood from each study participant and small tissue samples from their triceps before and right after each workout, as well as 90 minutes and three hours post-exercise. The scientists then analyzed the men's blood and tissue samples to look for certain markers, such as specific proteins (including muscle glycogen, which is a fuel for exercise) and genes linked to endurance and muscle mass.

Here's what the researchers of the study found: After the lifting-only workout, the men's muscles had a slew of markers that are known to help muscles grow, such as proteins S6K1 and Akt. But after the cycling and lifting workout, their muscles had those markers and certain proteins that are linked to better endurance.

"These findings suggest that leg cycling prior to arm resistance exercise causes systemic changes that potentiate induction of specific genes in the triceps, without compromising the anabolic response," wrote the researchers of the study. Translation: It appears that getting in some solid lower body–based cardio before you do an arm workout can help enhance the results of your strength training.

Okay, but why is this, exactly? A big factor in this study was that the participants focused on lower body cardio before doing upper body strength training, says Albert Matheny, R.D., C.S.C.S., the co-founder of Soho Strength Lab, Promix Nutrition, and ARENA. "That's different than if you went for a run and then did squats," he points out. People who follow that kind of exercise routine (i.e. leg work, followed by more leg work) are less likely to get as many strength gains because their muscles will be more tired than if they didn't focus on the same muscle group twice, says Matheny.

Still, "some kind of warm-up prior to lifting weights is a good idea," notes Matheny. This can extend to other forms of cardio, such as running, he adds. (See: The 4 Best Warm-Up Exercises You Can Do Before Any Workout)

"A warm-up is great to get your heart rate up, to get your system firing neuro-muscularly, and to get your blood flowing," says Matheny. But don't opt for too intense of a workout before strength training, he cautions. "This doesn't mean you should do a 45-minute intense cycling class and then go lift weights. That can be really tiring and make it harder to lift," explains Matheny.

If you're planning to pair resistance training for your arms with your cardio workout, consider doing an exercise such as shorter interval cycling exercises (such as a 20-minute or 15-minute ride) or a jog beforehand, suggests Matheny. "It's a good idea to get your heart rate up before you lift," he says. "If you sit at a desk and then try to do squats or bicep curls, you're probably not going to move as well as if you did a warm-up first," says Matheny.