A question that I am often asked and one that I have seen countless times on message boards across the Internet is whether a person should do cardiovascular exercise before or after a resistance training workout? Before going any further, I want to clearly state that it is my position that everyone should engage in a cardiovascular exercise of their choice for 5 to 10 minutes prior to any workout, be it a cardiovascular, resistance or flexibility workout. This is vitally important for several reasons as a proper, light-intensity cardiovascular exercise will warm up the muscles, ligaments, joints and tendons that will be used more intensely in the following workout routine. Warming up with cardio also increases the core temperature slightly, increases circulation, slightly elevates the heart rate and helps to prepare the heart for an increased workload, it helps increase lung functioning and helps you to mentally focus in on the upcoming workout routine. The most important advantage to warming up with light intensity cardio is the substantial decrease in risk of injury. If the body is not properly warmed up, you are much more likely to experience an injury to a muscle, joint, ligament or tendon.
Now back to the question of whether you should do cardiovascular exercise prior to or after a resistance workout? There is no single best answer here and instead, you should evaluate your individual fitness goals. If you goal is to increase endurance, stamina or overall cardiovascular health, then I suggest doing your cardio workout prior to weight and resistance training. By doing the cardio workout first (after your 5 to 10 minute warm up of course), you are able to engage in a more intense cardio session, which possibly might include some intervals in which you really push up to your lactic acid threshold or VO2 max level. It is much less likely that you would be able to achieve high intensity cardiovascular work after you have engaged in a weight training session. So, in short if your goal is to increase cardiovascular fitness levels, you should perform cardio workouts prior to resistance training.
On the other hand, if your goal is fat and weight loss, a current mode of thinking in the fitness community is by doing a cardiovascular workout after a resistance workout, you increases the rate of fat metabolism (fat burn as it is often referred to as). The theory is that by engaging in an intense resistance workout, you will deplete the glycogen stores in the muscles during this workout. Once the glycogen stores are depleted, the body begins to utilize fats in the body for fuel. Endurance athletes have long know this, yet typically in order for this to occur in endurance training, an athlete has to continuously run for approximately 90 minutes to fully deplete the muscles of glycogen. Therefore, I remain somewhat skeptical that many average people working out are pushing themselves to the point of glycogen depletion during their resistance workout, particularly workouts of less than an hour in duration. For more advanced trainers, I do believe that it is possible and therefore can be an effective means of decreasing body fat perhaps for these individuals.
I tend to look at it like this, if you are engaging in a cardiovascular and resistance workout on the same day back-to-back, one or the other will be of a lesser intensity level naturally. Again, evaluate your personal fitness goals before deciding whether to do your cardio workouts before or after resistance training. If you are trying to build muscle, you want to have as much muscle strength as you can available for your resistance workouts, therefore doing cardio before weight training would be counterproductive to your muscle building goals. If you are looking to gain endurance or heart health, place your focus on the cardio workouts and do them first. Remember, regardless of which you end up doing first, it is more important to properly warm up with a minimum of 5 to 10 minutes of cardio (even if it is only a brisk walk on the treadmill) in order to prepare the body for the workouts ahead, to get your head in the right space in order to bang out a productive workout, and most importantly to decrease the risk of injury. This debate won’t mean a thing if you get injured 5 minutes into a workout and are sidelined for the next 8 weeks rehabilitating an injury!