Finding Your Fitness Rhythm: The Case for Zone 2 Cardio

When it comes to cardio, not all workouts are created equal. And not all of them need to leave you out of breath and drenched in sweat. In fact, one of the most effective ways to improve your heart health, build endurance and reduce your risk of chronic disease might be surprisingly doable. It’s called Zone 2 cardio.

While the term “Zone 2” might sound technical, the concept behind it is straightforward: moderate-intensity movement that’s sustainable over time. To help break down what Zone 2 cardio is and why it matters, we spoke with Melissa Crews, a certified professional trainer and certified health coach with Memorial Hermann.

“In the context of low-, moderate- and high-intensity workouts, Zone 2 refers to the one in the middle, that sustainable sweet spot many people like to aim for,” Crews says.

What Exactly Is Zone 2?

Zone 2 is a moderate-intensity level of exercise, sitting just below what Crews describes as the second ventilatory threshold (VT2).  That is the point where the body begins shifting from aerobic to anaerobic metabolism. In simpler terms, it’s the point at which your breathing becomes noticeable but not strained, where you can carry a conversation but may find singing to be a challenge.

Unlike high-intensity efforts that primarily burn carbohydrates, Zone 2 workouts are fueled largely by fat, which means they can help improve metabolic efficiency over time. This is also the zone most referred to in national health guidelines. “When you hear the CDC say, ‘you need at least 150 minutes of moderate physical activity per week,’ Zone 2 is the level of workout that they’re speaking of,” Crews says.

The CDC’s recommendation aligns with research showing that just 150 minutes of moderate activity each week significantly can reduce the risk of heart disease, stroke, type 2 diabetes and even certain cancers.

How It Feels—and How to Know You’re There

While fitness trackers and apps may use terms like “fat burn” or “cardio zone,” Crews advises a more intuitive approach for most people. In practice, Zone 2 cardio feels manageable but active. You’re likely to break a light sweat with Zone 2 activities.

Crews suggests using the “talk test” or the Rate of Perceived Exertion (RPE) scale instead. “If you are able to speak—but not necessarily sing a complete sentence—that’s when you know you’re in that moderate range.”

The Benefits of Staying in the Middle

While high-intensity workouts often get the spotlight, Crews emphasized that Zone 2 training offers an impressive range of benefits without the physical toll of more aggressive exercise. “You decrease your risk of chronic diseases, heart disease, type 2 diabetes, strokes and even some cancers,” she says.

Crews also explained how regular, moderate cardio improves circulation, oxygen uptake and heart and lung efficiency. “When you get about 150 minutes of moderate physical activity per week, your blood is pumping and your lungs are working correctly. Everything’s kind of working behind the scenes in the way it should,” she says. “At this level of intensity, you also begin to burn fat more efficiently because your body shifts from burning glucose to burning fat as its primary energy source.”

Zone 2 cardio also supports mental well-being. “It’s a great way to release stress,” she said, pointing to exercise’s ability to regulate cortisol, the body’s primary stress hormone. “When you manage your stress, you’re able to function more efficiently throughout the day.”

Start Where You Are

Not everyone begins their fitness journey at the same place. Crews understands that and encourages people to honor their starting point.

“I have a soft spot for beginners and those returning from injury or postpartum because I had an injury and had to take some time to build up my base,” she explains. “I was trying to go all in, working out hard immediately after my injury. Unfortunately, my body was not ready for that.”

For those who are new to working out or recovering from an injury, Crews urges a focus on consistency and sustainability. “Walking is going to build your endurance, even if it’s at a lower intensity,” she said. “If you start out with just five to 10 minutes of physical activity per day, and then you build upon that, you’re going to get stronger and faster.”

Remember to start where you are, go at your own pace and match your effort to your goals.

Although many people can self-regulate based on how they feel, Crews emphasizes the value of working with a professional, especially for those individuals on medications, dealing with chronic conditions or recovering from injuries.

“You want to make sure that your trainer has a credible education,” she says of fitness professionals. “There’s so much information out there on the internet these days, and you want to make sure that you’re getting the right information for you and not some fluff from an influencer trying to push a product or program.”

Whether you’re just getting started or refining a routine you’ve had for years, a health coach or certified personal trainer can help you tailor your program to your goals safely and effectively.

The Bottom Line

You don’t have to run a marathon to get meaningful cardiovascular benefits. For most people, Zone 2 is a comfortable, achievable pace that builds strength from the inside out.

“Listen to your body,” Crews said. “It’s the key to knowing where you need to start.” That might mean walking around the block today and working toward longer or faster sessions down the road. What matters most is building a sustainable routine that protects your heart, supports your mental health and helps you feel good in your body.

If you have concerns about exercise or existing health conditions, speak with your primary care provider before beginning a new program. From there, you can confidently move forward one moderate, heart-healthy step at a time.