Are Zone 2 Workouts *Really* the Best Way to Burn Fat?

You’ve heard the buzz around zone 2 training. In recent months, this viral trend has developed a near cult following—from newbie fitness enthusiasts to elite athletes.

Zone 2, which focuses on low-key workouts like walking, cycling, and swimming, promises high returns: It can boost your performance, health, and in the process, up your odds of living longer. 

Leading experts, like sports performance coach, Korey Van Wyk, C.S.C.S., also suggest it burns more fat than higher-intensity cardio like sprints or interval workouts. But does that mean it’s the best option for fat loss? 

About the Experts

Sean Sullivan, C.S.C.S., is a strength and conditioning specialist and co-founder of Matterhorn Fit. He’s trained Olympians and pro athletes.
Korey Van Wyk, C.S.C.S., is a sports performance coach and educator and former professor of kinesiology with degrees in nutrition and exercise science who specializes in human performance training.

What is Zone 2 Training?

Zone 2 training—aka aerobic training or steady-state cardio—is low-intensity cardio performed for an extended period of time (usually anywhere from 30 minutes to three hours). 

As long as you stay roughly between 60 and 70 percent of your max heart rate, you’re in zone 2, says sports performance coach Korey Van Wyk, C.S.C.S.  Don’t have a heart rate tracker? “You can also use methods like the Talk Test or breathing only through the nose” to ensure you stay in zone 2. In other words, if you can keep a conversation going during your workout, you’re likely in it. 

Does Zone 2 Training Burn Fat?

Short answer? Yes. Zone 2 uses a greater percentage of fat for energy than higher-intensity workouts (1). Because of this, zone 2 has often been nicknamed the “fat-burning zone.” 

Scientists have identified five training zones in total, based on your exercise intensity level, the energy source your body is using, and the approximate percentage range of your max heart rate. Keep in mind, exact ranges vary from person to person:

Zone 1 is the target for warm-up and recovery. When you’re in it, your heart rate hovers between 50 and 60 percent of your max, and your body burns fat for energy. Push a little harder and you enter zone 2. In these two zones, your aerobic energy production system is in charge. The aerobic system, which depends on mitochondrial function, converts oxygen and nutrients (like fat) into energy.

If your heart rate climbs above 70-80% of your max—during high-intensity interval training (HIIT), for example—you’ll start to move into zones 3, 4, and 5. In these zones, your anaerobic system shifts into gear. 

In this anaerobic state, your body gradually shifts to breaking down glucose, rather than fat, to provide you with a quicker source of energy (2). In other words, for any exercise above the upper end of zone 2, you’ll burn a lower percentage of calories from fat because your body can’t break fat down fast enough.

Why Fat Burn Doesn’t Equate to Fat Loss

Zone 2 training certainly can help with fat loss, but it’s not the golden ticket some people make it out to be. 

Here’s why: Burning a higher percentage of calories from fat during zone 2 training doesn’t mean you’re burning more total calories. And it’s the latter that determines whether the number on the scale will change. “To lose body fat, the most important factor is to create a caloric deficit—to burn more calories than you are consuming,” explains Van Wyk.

Zone 2 burns more energy from fat, but because it’s less intense, it burns fewer calories. 

Studies show that HIIT workouts often result in more total calories burned, and greater overall fat loss, particularly from abdominal fat (3). 

To make matters more complicated, researchers are learning that fat burn is just one piece of the weight loss puzzle. Factors like what you eat, when you eat, and how your body processes those nutrients (will it get stored in your fat cells or be used for muscle or tissue repair?) also play significant roles (3). 

You could increase the duration or frequency of zone 2 to burn more calories. But if you don’t like zone 2 work, it’s not the only way to lose body fat.

LOSE WEIGHT

What is Fasted Cardio and Should You Do It?

Can You Build Muscle in a Calorie Deficit? 

Why Fat Burn Matters For Performance and Health

If zone 2 isn’t the ultimate key to fat loss, is it worth doing? Absolutely. Beyond burning fat, “[zone 2] training builds aerobic efficiency and endurance, and enhances recovery,” says certified personal trainer Sean Sullivan, C.S.C.S. 

As you exercise in zone 2, you significantly improve the efficiency and adaptability of your mitochondria (2). The more adaptable these cellular powerhouses are, the more energy they can generate during exercise. The more energy you have during exercise, the better your overall endurance and performance. Athletes who have higher mitochondrial function produce lactate more slowly (meaning they get tired less quickly) and burn fat more efficiently than less fit individuals (4). 

As you improve aerobic performance and become more fat-adapted, you also reduce your risk of stroke, heart disease, diabetes, and cancer (5, 6, 7, 8).

How to Use Zone 2 Training

Experts share that the best way to use zone 2 training depends on your goals.

For weight loss

Remember: creating a caloric deficit is the most important factor for weight loss. If slimming down is your goal, use zone 2 training to increase your overall calorie burn. 

Van Wyk suggests starting with two or three 30-60 minute zone 2 sessions a week. 

To dial up the fat burn, add in some HIIT or resistance training workouts. If you want the majority of weight loss to come from body fat (as opposed to both fat and muscle), aim for two 30-45 minute resistance training workouts per week and one to two HIIT workouts. 

As you start to lose weight, gradually increase the frequency and duration of your zone 2 training to continue to burn fat. “Once your weight loss goals are met, regular zone 2 sessions maintain fitness and metabolic flexibility,” Sullivan says. 

Training volume should also be adjusted to balance fat loss with muscle maintenance, Sullivan adds. Since you have limited energy to give to each, the goal is to find the optimal “stress and strain” to make continued progress on both fronts. 

For performance

If your focus is boosting overall performance and aerobic capacity, incorporate zone 2 training three to five times per week, says Sullivan. “This type of training builds aerobic efficiency [and] endurance, and enhances recovery.”

Sullivan also stresses the importance of a “well-rounded” training program, even if you’re mainly focused on power, speed, or strength. Zone 2 builds your training capacity. A wide training base allows you to do more challenging workouts (from sprints to heavy lifting) more efficiently—ultimately increasing peak performance. 

If you’re worried about your gains, don’t be. According to Van Wyk, zone 2 “will. not have a detrimental effect on strength, power, or muscle gain.” In fact, for most people, zone 2 training enhances results.

Still, Van Wyk recommends dialing back to one to two zone 2 sessions of 20 to 30 minutes if strength or hypertrophy is your primary goal. Mainly because you only have so much energy to devote to your workout sessions, and excessive cardio can tap into your gains if your routine isn’t carefully balanced. 

Recovery

Zone 2 training doesn’t drain your body like higher-intensity work, so it can help reduce burnout risk if you train often. For high-level performance, it can serve as restorative active recovery. And for weight management, it allows you to burn some calories without putting as high of a strain on your muscles or joints.