Cardio may be aerobic or anaerobic in nature. Aerobic cardio implies an intensity level less than 65% of your heart rate reserve (HRR) whereas anaerobic cardio is greater than 65% HRR. Traditionally, aerobic cardio had been considered the best way to burn bodyfat since fat is the primary fuel for energy at lower intensity levels for longer exercise durations. Nowadays, anaerobic cardio has been recommended as a much more efficient method of burning bodyfat for shorter exercise durations at higher intensity levels. Why? Because the metabolic rate of a person is at a more elevated rate hours after a hard cardio session has been completed, facilitating more caloric expenditure and fat burning in the resting state. See exercise post oxygen consumption (EPOC) elsewhere in this blog for more information.
Which should be performed first--cardio or weight training? The order of exercise should probably be based on your fitness goals. If your objective is to lose bodyweight or bodyfat, you should prioritize cardio. On the other hand, if your goal is to increase muscle mass, strength, or power, you should perform weight training first while you have the most energy. To lean out and gain muscle mass and strength, the best option may be to perform weight training first before cardio due to increased lipolysis (i.e., fat burning) that tends to occur during cardio after weight training. Weight training tends to burn mostly carbohydrates for fuel since carbs are a more immediate energy source of energy. Thus, performing cardio immediately after a weight training workout will force your body to rely on mostly fat for energy after your carb source of energy has been depleted.
Other options instead of performing cardio and weight training in one workout session are the following:
- perform cardio in the mornings and weight training in the afternoons/evenings
- perform cardio and weight training on separate days
BOTTOM LINE: Generally, cardio should be performed first if your goal is to lose bodyfat. Perform weight training first if your goal is to increase muscle mass or get stronger. Regardless which order you perform cardio and weight training, the important thing is to perform both regularly to maintain strength and a healthy cardiovascular system.
Brian Danley, CFT
"Motivation is what gets you started. Habit is what keeps you going."