Which comes first, cardio or strength? The question is often raised by those who work out regularly and want to maximize their time and fitness. Is it better to start your workout with aerobic activity on the elliptical, treadmill, or stair climber and then move on to lifting weights, or is that backward? 

The answer depends largely on what your fitness goals are. If your focus is on the health benefits of exercise rather than athletic performance, the simple answer is that it really doesn’t matter. Despite varying opinions on the subject, there is very little scientific evidence that doing aerobic training before strength training or vice-versa is more advantageous for good health. So for the average person, it really comes down to personal preference.

For the competitive athlete though, things get more complicated. When the primary goal is athletic performance, the training regimen should match up to the specific goal of that sport. For example, muscular strength and power are important performance factors for anaerobic sports such as football and volleyball. Therefore, it makes sense for these individuals to devote most of their time and energy into strength and power training followed by aerobic training as time and energy permits. 

For an endurance athlete, aerobic fitness is much more important than muscular strength. It makes sense for these athletes to devote most of their time and energy to aerobic training. Any time or energy remaining following these types of workouts can then be devoted to strength and power training. 

Busting the Fat-Burning Myth

One of the many popular “fat-burning” myths is that strength training should be done first in order to deplete muscle glycogen (stored carbohydrate) levels to burn more fat later during the aerobic training portion of the workout. There are two reasons why this doesn’t make sense:

1. Glycogen is only used in the specific muscles being worked. If someone performs an upper body strength workout, then it will have absolutely no impact on muscle glycogen levels in the legs. In other words, performing an upper body workout prior to a run or a bike ride will not affect muscle glycogen levels in the legs. 
2. Depleting glycogen in legs is more difficult than you think. Performing one or two sets of a few leg exercises will not have much impact on muscle glycogen levels, nor will it increase “fat burning” during subsequent aerobic training. Even if you start with lower body strength training before aerobic training, you would have to do multiple exercises, sets and reps to significantly reduce leg muscle glycogen levels. Very few people perform such an exhaustive strength training regimen. 

The Bottom Line

If your primary exercise goal is to maintain or improve your health, then it really doesn’t matter whether you do your strength training or aerobic training first. If you are doing both on a regular basis, then you should be very proud of yourself since only 20% or so of American adults are meeting the minimum public health guidelines for physical activity. 

If weight loss is your primary exercise goal, then you need to focus on burning more calories each day than you consume. You are likely to burn about the same total number of calories whether you do strength training or aerobic training first. Bottom line - try both approaches and stick with whichever one feels best to you.