Science Takes a Look: Cardio First or Strength First?

Cardio first, then strength training? Or strength, then cardio? Which is best? You’ve probably hear the bro-science, now let’s take a look at what the real researchers discovered about our hormones.

Do you ever perform both strength training and aerobic training during the same session? Have you ever wondered “Which should I do first, and why?” Today’s study from the Journal of Strength and Conditioning Research examines that question. Specifically, it looks at the hormonal response to performing different types of exercise in different orders, and how that might affect our training.

The hormones testosterone and cortisol are critically important to training and athletic development. Testosterone is anabolic and promotes muscle growth. Cortisol is catabolic and retards muscle growth. These two hormones were the focus of the study.

Study participants all performed two training sessions: a strength session and an aerobic session. Strength training was 3 sets of 8 reps in bench press (of course), Smith machine squat (because one can’t be expected to support the bar on his own), lat-pulldown (because pull-ups are too hard), and knee extension (because you should train a moving knee joint with a static hip joint, even though that never, ever happens outside the knee extension machine. Okay, I’m done whining about the exercise choices). Aerobic training was 30 minutes of pedaling on a stationary bike at 75% of maximum heart rate. Sometimes the strength training came first and sometimes the aerobic training came first. Participants had blood taken and hormone levels measured before, during, and after the training sessions.

The results? No matter what you do first, aerobics or strength, testosterone and cortisol levels rise. Both hormones are elevated between the two sessions compared to when you began training. There was a difference, though. If you did aerobics first, then testosterone continues to rise slightly through your strength training session. But if you did strength first, then testosterone begins to slightly fall during the aerobic training. Cortisol was rather boring. It acted pretty much the same no matter the order of exercise.

Conclusion: performing aerobic training before strength training keeps testosterone levels elevated longer. This is a unique and powerful finding, but I want to couch it with some caveats. First, the study uses pretty bland versions of both strength training and aerobic training. What if the strength training used more compound lifts? At higher intensities? What if the aerobic training used intervals? All of these factors could produce a different result. That’s not to say the study was poorly done. You can’t study everything at once. You have to start somewhere. But I wouldn’t extrapolate these results to every single situation where one type of training follows another.


1. Cadore, Eduardo, et. al. Hormonal Responses to Concurrent Strength and Endurance Training with Different Exercise Orders. Journal of Strength and Conditioning Research 26:12, 3281-3288, Dec 2012.

Photo courtesy of Shutterstock.