Build your endurance and improve your half marathon and marathon performance.
Zone 2 training is the often underestimated secret to building a solid aerobic base that will allow you to run longer and stronger. Let's find out why it's so crucial and how to integrate it into your plan.
What is Zone 2 Training?
Zone 2 training refers to physical activity performed at a low, controlled intensity, corresponding to approximately 60-70% of your maximum heart rate (HRmax). It's a sustainable pace, often called "conversational pace", because you should be able to talk without gasping for air.
Physiologically, this is the optimal intensity to stimulate mitochondria, the powerhouses of our cells. Training in Zone 2 increases their number and efficiency, improving the body's ability to produce energy. Furthermore, it teaches the body to use fats as the primary fuel source, a process called lipid oxidation. This makes your body a more efficient "hybrid engine", capable of saving precious glycogen stores (sugars) for moments of higher intensity effort.
Key Benefits
Building the Aerobic Base
Efficiency in Fat Utilization
Increased Mitochondrial Density
Improved Recovery & Injury Reduction
Mental Sustainability of Training
Beware of "Zone 3"! Many runners perform their easy runs at too high a pace, ending up in this "no man's land": too mild for speed stimuli, too intense for aerobic benefits.
Calculate Your Heart Rate Zones
Enter your age to generate comparative tables with training zones. The two most common methods will be used (the classic Cooper and the more modern Tanaka). For each, you will see a comparison between standard percentage ranges and alternative ones suggested by some coaches.
Enter your age to view the zones.
How to Incorporate It into a Training Plan
An effective approach is the 80/20 principle: about 80% of the weekly training volume should be at low intensity (Zones 1-2) and only 20% at high intensity.
The Long Run
This is the most important session and should be run almost entirely in Zone 2. The goal is to progressively increase the duration (e.g., up to 18-20km for half, 32-36km for marathon) to accustom the body to being on its feet for hours, optimizing fat use.
The Easy or Recovery Run
These are shorter runs (45-75 minutes) to be inserted on days following intense training. They help recovery and add "aerobic quality" miles without tiring the body.
Frequently Asked Questions (FAQ)
Use the "Talk Test": you should be able to hold a full conversation without effort. If you can only say a few words at a time, you're going too hard. In terms of Rate of Perceived Exertion (RPE), it should be an intensity between 3 and 4 on a scale of 1 to 10.
Yes, it's absolutely normal, especially at the beginning. Many runners are surprised by how much they need to slow down. Be patient: with consistency, your aerobic system will become more efficient, and you'll notice that your running pace will gradually increase at the same heart rate (in Z2). This phenomenon is known as "aerobic decoupling" and is a sign that you are improving.
To achieve significant benefits, a Zone 2 session should last at least 45-60 minutes. Long runs, essential for the marathon, will obviously last much longer, even several hours. Duration is more important than distance: the goal is to accumulate time at low intensity.
Zone 3, or "tempo pace", is a "grey zone". It's not intense enough to stimulate adaptations for speed (like raising the lactate threshold), but it's too tiring to allow for optimal recovery and to fully develop the aerobic efficiency of Zone 2. You end up accumulating fatigue without maximizing the specific benefits of any zone.
No, a balanced training plan is key. Zone 2 builds the "foundation", but to build the "upper floors" (speed, power, race pace), you need high-intensity workouts like intervals, tempo runs, and fartleks (the 20% of the total). The combination of polarized training (mostly easy, some hard) is the winning strategy.
Absolutely. Zone 2 is based on heart rate, not the type of activity. Treadmill, stationary bike, elliptical, or even swimming are excellent for accumulating time in Zone 2, especially if weather conditions are adverse or if you need to reduce impact on joints.
This phenomenon is called "cardiac drift". It's normal for heart rate to slightly increase during prolonged activity even at a constant pace. It's caused by factors like dehydration and increased body temperature. Good aerobic training helps reduce this drift over time.
The Karvonen formula, which considers Resting Heart Rate (RHR), is generally considered more accurate because it personalizes zones based on individual fitness levels. However, calculation based on HRmax is simpler and provides a very good estimate, especially for beginners. For maximum accuracy, a field or lab test to determine your actual HRmax is the best option.
Yes. Since Zone 2 promotes fat utilization, a balanced diet that doesn't overdo simple carbohydrates can support this adaptation. Some athletes experiment with fasted Z2 workouts (for short sessions, < 90 min) to maximize fat oxidation. However, ensuring proper hydration and comprehensive nutrition is always crucial for recovery and overall health.
Age-based zones don't change frequently. However, your actual HRmax and Resting Heart Rate can vary with training levels. If you don't perform specific HRmax tests, recalculating age-based zones more than once a year isn't necessary. It's more useful to monitor how your pace improves within the same heart rate zone.
