Whether you are new to working out or have been doing it for years, you may be wondering whether it’s better to do your cardio before or after your weight training.
Generally speaking, it’s best to do cardio after weights. The reason for this is that when you push yourself during weight training you should use up your glycogen (carbs) as your primary source of energy. Once you have used up your glycogen stores in your weight lifting session you can complete your cardio with the idea that the energy you will be burning will primarily be coming from fat (because you used up your carbs for lifting). This is the principle behind cardio timing when trying to maximize fat loss but still having enough energy to complete a full workout.
Science aside, have you ever tried to lift weights after an intense cardio session? If you have then you know that your energy is typically lacking after cardio (you just burned up all your glycogen and fat is slower to be utilized for energy) and what’s more, you’re just plain drained! On the flip side, typically after an intense weight lifting session you feel energized and ready to tackle cardio so not only is it about what source of energy you are using to maximize fat loss, it’s about having enough energy to complete the whole workout.
One final important thing to recognize is that cardio timing relative to weight lifting is going to come down to individual goals and preferences because while you will find a lot of differing opinions on this topic, there isn’t a ton of reliable research on either side of the debate. We do have good research that tells us glycogen is the primary fuel supply that muscles use in weight training, especially in the first hour and glycogen is more readily available so our muscles have it quickly to utilize in those explosive and heavy movements that come from lifting heavy weights. Fat is not as readily available as fuel compared to carbs/glycogen making it more suited for a longer steady cardio session.
In summary, cardio after lifting with a well-balanced and calorically-sufficient diet is a recipe for maximizing fat loss!