Want to burn fat faster, especially in those trouble spots? Then stop zoning out to the wheeze of the treadmill. It’s time to switch up your routine with metabolic circuits!

“Metabolic circuits are a lot of fun and can really benefit your health and fitness,” says Lori Incledon in her book Strength Training for Women. The fitness world is abuzz over metabolic training because it delivers a super-effective workout for muscle gain AND fat loss. Did we mention you can do a circuit in 30 minutes or less?

“Metabolic conditioning” or “metabolic training” refers to exercise designed to replicate the types of exertion used in sports—high energy, high engagement, total body movements. The “circuit” is simply the cycle of exercises you set up in your routine.

So why does metabolic training lead to increased muscle mass and fat burn?

Reason #1: Metabolic Circuits Use Resistance Training

“Study after study shows health benefits from resistance training,” Craig Ballantyne told The Nate Green Experience, “After all, it doesn’t take a genius to realize that a good superset lifting session works your muscles and cardio-vascular system a lot better than a 30-minute walk in the park.”

As in sports, you’ll be doing some serious muscle multitasking in your circuit. By using compound instead of isolated movements, you work multiple muscle groups for a balanced, full-body workout.

Additionally, with brief rest periods, active rest, or simply resting one muscle group while you work the other, you’re able to do even more strength training in a short amount of time.

Increasing your lean muscle mass will accelerate your calorie burn, but to get the full effects, “you need to lift heavy,” says Jade Teta, ND, CSCS, “Your muscles should be burning.” The idea of a metabolic circuit is to get close to muscle exhaustion fairly quickly, so you shouldn’t be able to do 12+ reps in a set. If you can only lift 2-3 reps of a heavy weight while maintaining control and flawless form, that’s fine.

Reason #2: Metabolic Circuits Get Your Heart Rate High

By incorporating intense bursts of exertion at intervals—2 minutes of jumping jacks, say, or spinning on a bike as fast as you can—you’re getting your heart rate up for great cardiovascular benefits. Alternating between high intensity and low intensity (active rest) keeps your heart rate up, while allowing your body to rest between exercises.

As with the resistance component of your circuit, the goal is to emulate sports training, so focus on intensity over quantity. It’s not as important how long you jump rope, but that you do it as hard as you can. “You shouldn’t be able to talk,” Teta explains. So if you’re chatting with a pal or humming a tune, you aren’t making the most of your circuit.

Reason #3: Metabolic Circuits Generate Afterburn

Varied, high intensity exercise is proven to create EPOC (Excess Post-Exercise Oxygen Consumption), also known as “afterburn.” For one, you’re exerting energy at full capacity, which creates an oxygen debt. And two, the varied movements prevent your body from adjusting to your level of exertion and conserving oxygen (as it would in steady state exercise). So, metabolic circuits increase your energy expenditure during and after training, burning up calories to do so.

Are You Getting Full Metabolic Effects?

“There are four reliable ways to stimulate the maximum caloric burn both during and after the exercise session,” says Teta, “we call these the ‘Bs’ and the ‘Hs’: breathless, burning, heavy, and heat. Each workout should work to generate all four of these components.”

In other words, when you finish your circuit you should be wobbly, sweating, striving to catch your breath, and clawing for your water bottle. Your muscles should be fatigued, and if you’re just starting out, you can probably expect a few days of soreness.

You should not be dizzy, faint, precariously wheezing, or on the verge of pulling a muscle. It’s especially important when doing metabolic training to eat right and stay hydrated. You should also prevent soreness with stretching and foam rolling, both before and after your circuit.

Keep Your Circuits Short and Sweet

In your eagerness to get started, be careful not to over-train. If you’re a beginner, ease your way in slowly. Diving into an intense workout could easily cause injury, which is NOT going to get you any closer to your fitness goals. Nor are extended soreness, pain, or an inability to walk for two weeks.

The beauty of metabolic circuits is that they’re designed to be short and sweet, so you don’t need to overdo it. The goal of lifting in your circuit is to expend maximum strength with control and correct form. You’re not going to be able to do that for very long.

To get the most from your metabolic circuits, don’t push yourself beyond your capacity, and always allow adequate rest between heavy workout days. 30 minutes for 2-3 (non-consecutive) days a week should be plenty. If you’re a beginner, 10-20 minutes is just fine.

It only takes a short period of high energy, high effort, total-focus activity to get exceptional fitness results. So set up your metabolic circuit and start reaping the rewards!

Have you tried metabolic circuits? Can they replace cardio in your workout regimen, or do you do both?

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