Should you do cardio before or after strength training?
A question that I am often asked and that I have seen countless times on message boards across the internet is whether a person should do cardiovascular exercise before or after strength training. Before I continue, I want to make it clear that it is my position that everyone performs a cardiovascular exercise of their choice for 5 to 10 minutes before every workout, be it cardiovascular, resistance or flexibility training. This is crucial for several reasons, as proper low-intensity cardiovascular exercise warms up the muscles, ligaments, joints, and tendons that will be used more intensively in the following workout routine. Warming up with cardio will...

Should you do cardio before or after strength training?
A question that I am often asked and that I have seen countless times on message boards across the internet is whether a person should do cardiovascular exercise before or after strength training. Before I continue, I want to make it clear that it is my position that everyone performs a cardiovascular exercise of their choice for 5 to 10 minutes before every workout, be it cardiovascular, resistance or flexibility training. This is crucial for several reasons, as proper low-intensity cardiovascular exercise warms up the muscles, ligaments, joints, and tendons that will be used more intensively in the following workout routine. Warming up with cardio also slightly increases core temperature, increases blood flow, slightly increases heart rate and prepares the heart for increased workload, improves lung function, and allows you to mentally focus on the upcoming workout routine. The most important benefit of warming up with light intensity cardio is the significant reduction in the risk of injury. If the body is not properly warmed up, you are much more likely to injure a muscle, joint, ligament, or tendon.
Back to the question of whether you should do cardiovascular exercise before or after strength training. There is no best answer here. Instead, you should evaluate your individual fitness goals. If you want to improve endurance, endurance, or overall cardiovascular health, I recommend doing your cardio workouts before your strength and strength training. By doing the cardio workout first (after a 5-10 minute warm-up, of course), you can have a more intense cardio session, perhaps including a few intervals where you really reach your lactic acid threshold or VO2 maximum level. You are much less likely to be able to achieve high-intensity cardiovascular work after strength training. In short, if your goal is to improve cardiovascular fitness, you should do cardio workouts before strength training.
On the other hand, if your goal is fat and weight loss, a current mindset in the fitness community is to do cardiovascular training after strength training. They increase the speed of fat metabolism (fat burning, as it is often called). The theory is that by doing intense resistance training, you will deplete the glycogen stores in the muscles during that workout. Once glycogen stores are depleted, the body begins to use fats in the body as fuel. Endurance athletes have known this for a long time. However, to achieve this in endurance training, an athlete typically needs to run continuously for approximately 90 minutes to completely deplete the glycogen muscles. So I'm a little skeptical that many average people who exercise push themselves to the point of glycogen depletion during their resistance training, especially if they exercise for less than an hour. For more advanced trainers, I believe this is possible and therefore can be an effective means of reducing body fat, perhaps for these individuals.
The way I tend to look at it is if you do cardio and resistance training back to back on the same day, one or the other will obviously be of lower intensity. Re-evaluate your personal fitness goals before deciding whether to do your cardio workouts before or after strength training. When you're trying to build muscle, you want to have as much muscle strength as possible available for your strength training. Therefore, doing cardio before strength training would be counterproductive to your muscle building goals. If you want to gain endurance or heart health, focus on cardio and do it first. Remember, no matter what you do first, it is more important to warm up properly with at least 5 to 10 minutes of cardio (even if it's just a brisk walk on the treadmill) to prepare the body for the workouts in advance, to get your head in the right space, to start a productive workout, and most importantly to reduce the risk of injury. This debate means nothing if you get injured 5 minutes after training and take a break for the next 8 weeks to rehabilitate an injury!
Inspired by Dr. Christopher C Weaver, D.C