If you’re even slightly aware of the latest fitness trends, then you’ve no doubt been hearing the buzz about Zone 2 training.
For the uninitiated, zone training refers to a five-zone heart rate scale that each person individually determines based on their own heart rates at different levels of exercise intensity. Zone 2 is on the more relaxed end of that scale; it’s a training intensity that you could theoretically hold for hours. In learning about Zone 2, it’s easy to get lost in the weeds of all the metrics and methods: One moment you’re calculating percentages and ranges, then suddenly you’re trying to understand the purpose of lactic threshold and fartlek interval workouts. This information overload can be especially overwhelming for novice-to-intermediate runners.
Here’s the good news: zone training does not need to feel intimidating or out of reach. At its core, the concept is another external tool for better understanding our own bodies in relation to our fitness goals.
We set out to get a better sense of what Zone 2 training means on a practical level for our bodies and our psyches, and how novice and intermediate runners can reap its benefits. For this, we consulted experts including renowned sports cardiologist Dr. Benjamin Levine, director of the Institute for Exercise and Environmental Medicine in Dallas, Texas; certified run coach and running educator Elisabeth Scott; and running coach and long-time friend of REI, Malcolm Dunn.
Read on for the full article or click on the links below:
- What Is Zone 2?
- Health Benefits of Zone 2 Training
- Busting Zone 2 Myths
- Zone 2 Training for Beginners
- Zone 2 Training at Any Level
- Psychological Benefits of Zone 2 Training
What Is Zone 2?
Broadly speaking, zone training is a way to break-down running into five levels or zones. Metrically, these zones are defined by your heart rate at different degrees of exercise intensity ranging from rest to maximum. You are technically running in Zone 2 when you’re at ~65-75% of your maximum heart rate, which you can determine using a heart rate monitor or fitness tracker and completing a high-intensity workout within your ability level. (We advise against using age-based formulas to determine heart rate zones: There is no universal max heart rate.)
- Physiologically, Zone 2 is the heart rate intensity zone that occurs before your lactate or ventilatory threshold, meaning, before the point where lactic acid begins accumulating in your blood and you start to breathe harder.
- Metabolically, the zones are distinguished by what your body is using for fuel: fat or glucose. In Zones 1 and 2, you’re burning primarily fat; as you shift into the higher zones, more and more of the fuel comes from carbohydrates.
- Practically, the zones are defined by their respective effort and sustainability—from the very low effort of Zone 1, which you could keep up indefinitely, to the extreme effort of Zone 5, which most people can only sustain for a few seconds to minutes. Within this range, Zone 2 is a low-to-moderate-intensity pace—one that can be sustained for several hours, but not indefinitely. Generally speaking, you should feel pretty relaxed for most of a Zone 2 run, and if you’re running alone and in an uninspiring location, you might even be a bit bored .
Health Benefits of Zone 2 Training
For many beginner to intermediate runners, staying in Zone 2 will require you to do run/walk intervals rather than running continuously. Some runners will try to complete most of their Zone 2 training on a bike or elliptical, since the lower impact makes it easier to keep the heart rate relatively low. Whatever method you choose, there are significant benefits to training in this zone, especially for 40-plus minutes. Let’s get into it.
Performance Benefits
If you think of your cardiovascular system as an engine, then it would make sense that you need to strengthen the overall apparatus before you start fine-tuning other parts of the machine. While high-intensity training can sharpen your abilities as a runner, slowing down helps you build a foundation to support that faster, more taxing training. As a result, Zone 2 training is the basis of major performance gains for most runners, from beginners to advanced athletes. Even elite runners benefit from training in Zone 2 for the majority of their runs.
When you run in Zone 2, you’re training your body at the systemic level, explains Malcolm Dunn, who holds master’s degrees in both kinesiology and exercise sports studies. “You are training your body to be more efficient in the uptake of oxygen,” he says. These adaptations allow you to perform better not just in Zone 2, but in all the zones.
Endurance Benefits
When most runners think of endurance, they imagine being able to cover long distances with relative ease. But when getting through a single mile feels tough on the body, building cardiovascular endurance can feel out of reach. This is where Zone 2 comes in. Scientifically, endurance can be understood as the ability of our cardiovascular system to supply oxygen to our muscles. Dr. Benjamin Levine, cardiologist for many collegiate and professional sports teams as well as NASA, says that at only 50% effort, we are already pumping the maximum amount of blood per beat, with the heart operating at its highest stroke volume. This means that even in lower-effort running, you are stimulating the process of “exercise-induced cardiac remodeling,” in other words, endurance. The result? Your heart becomes physically stronger, allowing you to workout harder and longer without becoming fatigued.
Recovery Benefits
In many ways, training in Zone 2 training is the best of both worlds: you are increasing blood flow to your muscles without putting significant strain on those muscles. Among other benefits, this moderate approach aids in recovery. “It allows us to accumulate a lot more training volume without accumulating an overload of training stress,” explains running coach Elisabeth Scott. For Scott, a big part of working with her clients to become better, smarter, faster runners is encouraging them to embrace the importance of that “easy-effort” zone. “The core of my mission is getting people to slow down on their easy runs,” she says.
Busting Zone 2 Myths
Before you get caught up in nailing your Zone 2 runs, it’s important to remember: There is nothing inherently magical about any one training zone. Moving between Zone 2 and 3 is not a distinct physiological process; it is just a description that can be helpful (or not). And the heart rate zones you’ve estimated for yourself are likely not 100% accurate under all circumstances —it would take a lab test as well as adjusting for a variety of external (like heat and altitude) and internal conditions (medications, other medical problems) to know if you’re running in your Zone 2 on any given day.
Overwhelmed? Don’t worry. Here are some ways to rethink the Zone 2 conversation:
The Zone 2 Misnomer
In the mainstream, Zone 2 has become a catch-all phrase to describe easy-effort running at a pace below our lactate threshold. However, Zone 2 actually refers to a very specific placement within the five-zone heart rate model. “We’ve co-opted this one specific label to apply broadly to this entire type of training,” Elisabeth Scott explains. This can be pretty confusing, because it suggests that an easy-effort run is only meaningful when it’s within a specific heart-rate range, and this just isn’t true.
Even if you’re technically not running in Zone 2, if a run feels easy (you can have a conversation during the run, you feel like you could go for hours, you finish the run relaxed or energized), you’re benefiting from low-to-moderate intensity training.
Beyond Heart Rate
All of the experts we spoke to encouraged novice runners to avoid getting too obsessed with the minutiae of zone training. The truth is, there are many metrics to determine if you are in that golden range of easy-effort running.
- Perceived effort: Dunn encourages runners to think in terms of their own subjective scale from 1 to 10. When we’re running at a 2-3 pace, it’s easy and we could do it indefinitely; at 10, it’s so hard that we can’t do it for more than 5 or so seconds. In this scale, what we call Zone 2 will fall in the 4-6 range of effort.
- The talking test: If you’re running in Zone 2, you should be able to carry on a conversation, offering full-sentence responses, but speaking in a monologue would be difficult.
- The singing test: No one to talk to? Try singing. Dr. Levine says that if a pace is low-to-moderate intensity for you, then singing will not be easy but it will be possible: “You could get a few bars out.”
What’s more, even if you determine your Zone 2 heart rate metrically, it’s a good idea to use at least one of the above tests to confirm that you are indeed in your low-to-moderate intensity range. Scott says she knows she’s done a Zone 2 run if, at the end of the run, she feels like she could have kept going a lot longer.
Hard Data Isn’t Everything
There is nothing wrong with having a variety of tools to understand your training. However, there is no replacement for learning to listen to your body. “A lot of what I do as a coach is helping people break away from trying to use one metric specifically,” Scott says. After all, there’s real value in learning to trust yourself. “What makes us successful as runners is not just looking at the numbers but learning to ask ourselves, ‘How does this feel?’” she explains.
It Takes Time
Zone 2 training takes more of a time commitment than more “time-efficient” workouts such as interval training. “To really see benefits, you do have to do it longer than some of the training in other zones,” explains Dunn. “For running, the ideal minimum is 20 minutes, but the peak benefits are going to be in 40 to 60 minutes and beyond.”
Zone 2 Running for Beginning (or Returning) Runners
For a variety of reasons, when you're just starting running—whether for the first time or after a significant break—running below your lactate threshold might mean not running at all. Instead, it may mean walking or completing walk/run intervals, where you run for a period of time and then walk for a period. This is because the zones tend to contract for runners who are beginning or resuming a running journey; meaning, going from a walk to a light jog might bring their heart rate all the way up to Zone 3 or 4.
Scott equates it to the gears on a bike. “When you’re a newer runner, or novice or returning, you’re basically running like a fixed-gear bike,” she says. “You have one speed, maybe two speeds.” As you gain fitness over time, you will find more delineation between zones. Until then, the reality for a lot of runners is that their Zone 2 includes walking.
But is walking really helpful? Some may worry if they're actually getting the benefits of low-to-moderate-intensity cardio by walking. Our experts agree: Absolutely. “If someone’s Zone 2 is walking, then walking is totally it,” Dunn confirms. For Scott, a successful run is the right amount of time in the right intensity zone. “If walking allows me to stay in that zone, that’s 100% a success,” she says.
The zones can be a distraction. Even if you do slip into Zone 3 or 4 during a light jog, you haven’t “failed” your run. “People overthink training, especially at the beginning and worry if their smart watch reads too high,” says Dr. Levine. “If your heart rate drifts up too high, your heart isn’t going to explode.” When we get overly attached to metrics, we can forget the most important thing, which is, he says, “to find something that you’re going to do on a regular basis and do it.” Elisabeth Scott agrees. She doesn’t begin thinking intentionally about zone training with clients until they are running more than 90 minutes or two hours each week. Until then, she says the focus should be “getting out the door on a regular schedule.”
Slowing down takes discipline. “Psychologically, slowing down that much is very difficult,” Elisabeth Scott says. After all, most of us started running because we want to do exactly that—run, not walk. The good news? With consistency, your Zone 2 pace will become faster. Eventually. “Your easy-effort zone fitness is the last thing to change,” Scott warns. “I call it the caboose of your fitness.” If you’re at the beginning of your running journey, try turning the focus away from pace and towards feel. If you’re finishing your runs with the genuine desire to run again, you’re on the right track.
Reaping the Benefits of Zone 2 at Any Level
Whether you are an experienced athlete or simply trying to improve your overall fitness, there are significant benefits to running at the conversational pace we call Zone 2. Usually, these benefits are discussed in terms of performance, endurance and recovery, but there are other ways to think about it.
Improving you overall fitness. "If you want to do exercise for health you really don’t need to do much more than Zone 2 training,” says Dr. Levine. He’s quick to clarify that the ideal exercise regime will include more variety. His "prescription for life” includes one day a week of higher-intensity interval training, alongside 2-3 days a week of Zone 2 training, one longer session, and some strength training. But the fact remains that if you want the simplest approach to building fitness without taxing your heart, Zone 2 is your new best friend.
Building your base and cross-training for hiking and backpacking. Zone 2 training strengthens the very foundations of your running practice. Not only do our bodies become more efficient than baseline on the mitochondrial level , points out Malcolm Dunn, those transfer to other activities, like hiking. To illustrate this, Dunn uses the example of training for backpacking with Zone 2 runs. You’re most likely not going to be doing your Zone 2 workouts carrying a really heavy backpack up a steep hill. However, “the next time you do carry a really heavy backpack up a steep hill, then it’s going to be easier than it was previously.” However, to optimize mitochondrial efficiency, you will have to do some higher intensity training as well, points out Dr. Levine.
Get in more training hours, safely. One of the persistent concerns of any fitness endeavor is over-training, which is a real risk for those who bypass Zone 2. Elisabeth Scott has seen this first-hand. “Some runners end up never ever spending time in their easy zone,” she says. “Over time, as they run more and accumulate more volume and sophistication in their running, they end up burning out.” By contrast, Zone 2 does not put much strain on your body, making it a safe way to get a lot of time or mileage in. Dr. Levine, who runs the Institute for Exercise and Environmental Medicine (www.texashealth.org/IEEM), the largest research center for the study of human physiology in the United States, confirms: “[Zone 2] allows you to spend more time being physically active without exhausting yourself.”
Psychological Benefits of Zone 2
Beyond its physiological benefits, Zone 2 can improve your relationship to running. Whether you’re a new or returning runner looking to build confidence, or a seasoned athlete who could use a little bit of fun in your training—easy runs have psychological benefits:
- Confidence: This is a big one for beginners. At first, many of us can feel like less legitimate runners if we include walking in our runs. After all, aren’t we running to become runners, not walkers? But the mentality that easy-effort runs can and often should include walking makes the idea of slowing down feel purposeful, as opposed to feeling like a failure. It turns out that even the pros walk. “I walked on my run yesterday!” confirms Elisabeth Scott.
- Consistency: “The best exercise is the one that you will do four to five hours a week,” says Dr. Levine. Many people find, especially starting out, that lower-impact running is less intimidating, which means they are more likely to get out the door for a Zone 2 run than for, say, a grueling HIIT workout. And it’s consistency that matters most, says Dr. Levine. His advice: “Start slow, increase duration, frequency and intensity a little bit at a time over a period of months.”
- Enjoyment: Somewhere between optimization and training strategies, it can be easy to forget that running is allowed to be fun. There’s something beautiful about runs that are more meditative, says Elisabeth Scott. “They allow you to spend time with yourself.” Plus, she adds, “it’s nice to go on runs that don’t leave you feeling like you’re dying at the end.”
