Zone 2 Training: The Next Fitness Fad or The Missing Link to Longevity and Performance?

Zone 2 training is in right now. You’ve probably heard about it on podcasts, Instagram, and TikTok.

Right next to supplements like NMN and resveratrol, it has also been discussed as a potential tool for longevity and healthy aging.

What’s appealing about it are a few features:

• You can get your cardio in without gasping for air
• It might be one of the keys to overall health and longevity.

It’s not just popular with trainers and leading researchers, though. Even LeBron James, one of the greatest athletes of our time, swears by Zone 2 training. He once said, “I train in the low zone where I can still have a conversation. That’s where you build that aerobic base.” So if it’s good enough for the King, it’s definitely worth a shot.

Today we’re diving into the world of Zone 2 training. Does it live up to the hype? What are the benefits? How the heck do you do it anyway? Will I be bored doing that much cardio?

What is Zone 2 Training?

Per the cellular definition, Zone 2 is the highest energy level you can put out while keeping lactate below 2 millimoles. That is, it limits the amount of lactate you produce.

Zone 2 training focuses on moderate-intensity workouts that improve aerobic capacity, which is your body’s ability to take in, transport, and use oxygen to produce energy for physical activity.

It’s effective for improving cardiovascular fitness, promoting fat metabolism, and building a solid foundation of endurance that can help you crush higher-intensity workouts in the future.

The primary indicators of zone 2 training are as follows:

• Challenging but not too hard intensity, about 60-70% of your maximum heart rate
• Noticeable sweating and using slightly larger volumes of breath
• Continual talking is becoming challenging, but you can hold a conversation

To deeply understand Zone 2 training, we have to know the physiological aspects underlying it.

A Brief Review of Energy Systems

When you exercise, your body uses three different energy systems to produce energy: the aerobic, anaerobic glycolytic, and phosphagen systems. The aerobic system is the primary system for producing energy during moderate-intensity workouts, which is the focus of zone 2 training.

The aerobic system relies on oxygen to produce energy, using fats and carbohydrates as fuel. During zone 2 training, your body relies primarily on fats as fuel, which is why this type of training is effective for burning fat. Zone 2 training also improves the efficiency of the aerobic system, making it easier for your body to transport and use oxygen.

During Zone 2 training, the body relies on aerobic metabolism to produce adenosine triphosphate (ATP), primarily within the mitochondria of muscle cells. This process involves using oxygen to break down carbohydrates and fats, producing energy as ATP.

Stage 2 is ideal for fitness enthusiasts who regularly engage in physical activity or recreational sports or want to improve endurance, lose weight, and increase longevity.

The Heart Rate Zones and Their Energy Sources

Here’re the five training zones and their primary energy sources:

Zone 1: The primary energy source for Zone 1 is aerobic metabolism, which uses oxygen to produce energy, and you train at a lower heart rate. This zone is characterized by low intensity, and the body primarily uses fat as its fuel source.

Zone 2: Zone 2 also relies primarily on aerobic metabolism, but the exercise intensity is slightly higher than Zone 1. The body continues to use fat oxidation as its primary fuel source but also starts to use carbohydrates (i.e., glucose) as the intensity increases.

Zone 3: In Zone 3, your body starts to rely more heavily on anaerobic metabolism (glycolysis), which doesn’t require oxygen but produces energy less efficiently. Carbohydrates become the primary fuel source, and lactic acid accumulates in the muscles.

Zone 4: It demands high-intensity efforts, and the body relies almost exclusively on anaerobic metabolism. Carbohydrates are the main fuel source, and the accumulation of lactic acid leads to fatigue.

Zone 5: Zone 5 is a high-intensity training zone suitable for elite athletes, and the body relies almost entirely on anaerobic metabolism to produce energy. The primary fuel source is carbohydrates, and the accumulation of lactic acid leads to fatigue and muscle failure.

How to Determine Your Zone 2

You can monitor your cardiorespiratory exercise in numerous ways. Some options include VO2max, using percentages of maximal heart rate (HRmax), percentages of heart rate reserve (HRR), metabolic equivalents (METs), ratings of perceived exertion (RPE), lactate threshold test, and the talk test.

Obviously, some of these are more scientific, while others may be more practical.

Although the VO2max test is considered the gold standard for calculating cardiorespiratory fitness, accurately measuring VO2max is often impractical for fitness professionals because it requires you to perform a cardiorespiratory exercise at maximal effort and sophisticated equipment to monitor your ventilation response (oxygen consumed and carbon dioxide expired).

Arguably the most commonly used formula for estimating HRmax is 220 – age. However, this formula was never intended to be used as an instrument for designing cardiorespiratory fitness programs because maximal heart rate varies significantly among individuals of the same age.

For this reason, more appropriate regression formulas have been developed, such as the Tanaka formula, where HRmax is determined using the following formula: 208 – (0.7 × age).

Let’s use this formula to calculate your zone 2. For example, your age is 40 years. Your max heart rate and zone two will be as follows:

Tanaka formula:

• 208 – (0.7 x age) = HRmax
• 208 – (0.7 x 40) = HRmax
• 208 – (28) = HRmax
• 180 = HRmax

Your estimated HR max is one hundred eighty (180) beats per minute. Your zone 2 (i.e., 60-70%) heart rate will be:

• 180 x 60% = 108
• 180 x 70% = 126

So, your zone 2 heart rate should be between 108 to 126 BPM.

The more common way, which is as good a framework as any, is based on rating of perceived exertion (RPE). As Peter Attia says in Outlive, “Zone 2 is… going at a speed slow enough that one can still maintain a conversation but fast enough that the conversation might be a little strained.”

How do you find Zone 2 on a treadmill?

To hit zone 2 on a treadmill, I recommend using an incline treadmill and walking briskly. Although the incline may depend on your knees and fitness level:

• Start at six percent and three miles per hour for at least 15 minutes before testing your level or making an assessment.
• Then you have to use a lactate testing device to accurately check whether you reached your zone 2 or not and adjust your intensity accordingly.
• Your aim should be to reach about 1.7 to 1.9 millimoles in the lactate meter, considered zone 2.
• Before climbing on the treadmill, wash your hands with soap and water for the test.

However, if you don’t want to use or have access to a lactate meter, you can use another metric called rate of perceived exertion (RPE).

In zone 2, you can hold a conversation for an hour or an entire session, but it isn’t as comfortable as normal talking. You’ll be a little more strained. But if you can’t talk or hold a conversation and take heavy breaths, then you’re on the higher levels and need to lower the intensity to get back to zone 2.

All right, now let’s get into some other zone 2 training options.

Examples of Zone 2 Training Workouts

Check out the different zone 2 training workouts that you follow.

Example Zone 2 Aerobic Interval Program

Although any training program may vary on an individual’s fitness level and goals, the following is one example of a stage 2 cardiorespiratory program:

• Start by warming up for 5–10 minutes.
• Move into a 1-minute interval in zone 2, which is challenging to hard.
• After the 1-minute interval, return to zone 1 for 3 minutes.
• Repeat these intervals until the duration of the exercise session is complete.
• Cool down for 5–10 minutes.

Example Zone 2 Steady-State Aerobic Exercise

An example stage 2 steady-state workout can proceed as follows:

• Start by warming up for 3-5 minutes in zone 1.
• Increase intensity (e.g., speed, incline) until you reach zone 2, which is challenging to hard intensity.
• Continue the duration of the exercise session at this intensity.
• Cool down in zone 1 for 3-5 minutes.

Other Stage 2 Workout Examples

Steady-state cardio: This involves maintaining a steady, moderate intensity throughout the workout, such as a 45-minute bike ride at a consistent pace.

Fartlek training: This form of interval training involves alternating periods of higher intensity with periods of lower intensity. For example, a 30-minute run might include 1 minute of faster running followed by 1 minute of slower jogging or walking.

Low-impact cardio: Activities like swimming, rowing, and using an elliptical machine can provide a low-impact, full-body workout that keeps the heart rate in the Zone 2 range without putting much stress on the body.

Hiking or walking: These activities can be a great way to get into stage 2 while being gentle on your body. A brisk walk or hike in nature can also greatly reduce stress and improve mental health.

Group fitness classes: Many group fitness classes, such as spin classes, sprints, or dance-based workouts, can be modified to stay within the Zone 2 range.

Note: The key to Zone 2 training is maintaining a moderate intensity (i.e., continual talking is becoming challenging) that allows you to work on your aerobic capacity without pushing your body too hard.

Benefits of Zone 2 Heart Rate Training

Okay, let’s talk about that heart of yours. Zone 2 training is like a hug for your cardiovascular system. It helps strengthen your heart and lungs, increase blood flow, and improve overall circulation. It’s like giving your heart a big ol’ high-five and saying, “thanks for keeping me alive, buddy.”

Zone 2 training can also help your body become a fat-burning machine. By working out at a moderate intensity level, your body taps into its fat stores for energy, which can lead to some serious gains in the weight loss department. It’s like having a personal fat-burning fairy sprinkling magic dust on you every time you hit that Zone 2 sweet spot.

Here’re more benefits of zone 2 training:

Improve aerobic capacity: Stage 2 training improves your body’s ability to transport and use oxygen, which increases your aerobic capacity and cardiovascular adaptations. A strong aerobic base or capacity helps you exercise longer without getting tired.

Reduce the risk of injury: Zone 2 training is low impact, which minimizes the risk of injury. It also improves joint stability and strengthens muscles, reducing the risk of injury.

Increase performance: Zone 2 workout can also increase the activity of enzymes in aerobic energy production, further improving mitochondrial function. This improves performance for endurance athletes like cyclists, marathon runners, and swimmers.

Promote weight loss: During longer duration Zone 2 workouts, the body will start to rely more heavily on fat as a fuel source as glycogen stores become depleted. This is why Zone 2 training can effectively enhance fat metabolism and promote weight loss.

“What I have been seeing for 25 years, working with elite athletes is that [zone 2] is the exercise intensity where I see the biggest improvement in fat burning and the biggest improvement in lactic clearance capacity. Therefore, that means that the mitochondria is where you see the biggest improvement.” —Iñigo San Millán, Ph.D.

Improve overall health: This type of training improves your metabolic health and enhances your overall health by reducing your risk of chronic diseases like heart disease, diabetes, and obesity. This is because zone 2 training decreases your blood pressure, improves insulin sensitivity, and reduces body fat.

Improved mental health: Don’t forget about the endorphins. Zone 2 training releases those feel-good chemicals in your brain, making you feel like a superhero (or at least like you could take on a small army of minions). It’s like a natural mood booster, helping you feel energized and motivated both during and after your workout.

Improve mitochondrial health: The mechanism at the core of zone 2 is that it’s the level where you’re still using the aerobic engine, which means you’re producing energy with your mitochondria. Typically, mitochondria quality and quantity decrease with age. But by doing ample Zone 2 Training, you can keep your mitochondria in abundance and functioning well. 

Watch How Zone 2 Training can Increase Your Longevity:

Again, Attia is kind of the man on this stuff. So here it is from him.

 

How to Incorporate Zone 2 Training into Your Workout Routine

To incorporate Zone 2 training into your routine, follow these steps:

• Determine your Zone 2 heart rate range using one of the earlier methods.
• Choose an activity you enjoy, such as running on a treadmill or outdoors, cycling, or swimming.
• Start with 20-30 minutes of exercise at your Zone 2 heart rate range, gradually increasing the duration over time.
• Aim to do Zone 2 training workouts 2-3 times per week, with at least one day of rest in between. Remember, rapidly increasing frequency may lead to overtraining and inadequate recovery of the muscle fibers.
• Incorporate other types of workouts into your training plan, such as strength training and high-intensity interval training (HIIT).

How long (and often) should a zone 2 training workout be?

The amount of time and frequency of Zone 2 training workouts will vary depending on individual fitness goals, current fitness level, and other factors. However, a general guideline is to aim for 30-60 minutes of Zone 2 cardio at least 2-4 times per week.

Conclusion

Zone 2 training might not be the flashiest or most intense workout style out there, but it sure packs a punch when it comes to benefits. Working out at a moderate intensity level can improve your cardiovascular fitness, promote fat metabolism, and boost your mood simultaneously. Plus, you won’t have to worry about feeling like you got hit by a truck after every workout (unless you’re into that kind of thing).

So, whether you’re just starting out on your fitness journey or looking to mix up your routine, give Zone 2 training a try. Your heart, your waistline, and your mood will thank you. And who knows, you might just find that the Zone 2 training zone is your new happy place.

So, take a deep breath, lace up your shoes, and get ready to step into the Zone 2 training zone. Your body (and your brain) will thank you for it.

FAQs About Zone 2 Training

Is Zone 2 training worth it?

Zone 2 training is the most important place to be training your mitochondria.

To know the worth of zone 2 training, we first need to understand the mitochondrial function. And the crucial thing you need to know is that the deterioration of mitochondrial function is one of the hallmarks of aging, so anything we can do to delay that process and enhance mitochondrial function it’s going to benefit us, and the zone 2 training exactly does that to increase our longevity.

However, you’ll also get other benefits like improved cardiovascular health, weight loss, and a better quality of life. Remember, it may sound a little time-consuming, but the benefit you get is way bigger and one hundred percent worth your time.

Can I do other exercises before or after Zone 2?

It depends on your goals! Research shows that if your goal is hypertrophy or strength gain, finishing a strength training workout and jumping immediately into zone two may be counterproductive.

It may seem less of an issue, but separating them all in one day is better. For example, if you do strength training and zone 2 in one day, separate them by several hours (one in the morning and the other in the afternoon).

However, if you want to perform them simultaneously, it’s recommended to do zone 2 first, followed by strength training, so that you don’t eat into your strength goals.

That much cardio sounds boring. What should I do?

As an added bonus, it’s a great time to catch up on your audiobooks during your training. If you’re on the treadmill, you could even binge watch your favorite show.

Should I do Zone 2 before or after eating?

Although it depends on what you eat, if you eat something that spikes your glucose, it can impact your lactate. For example, if you eat a high-carb meal, your body will have more access to glucose than the stored fat, which can impair your zone 2, meaning you’ll tap out earlier as your body forces all the substrate to be glucose.

For this reason some people recommend you do your zone 2 training in the morning in a fasted state instead of faded to promote your body to metabolize fat and maintain the intensity throughout the session.