by One Playground
We’ve dived into the details of what your heart rate zones are, how to work out your zones and how our physiology changes in each in part 1 of our Heart Rate Zone Training Series. Now it’s time to get more specific to your goals and discover how to start heart rate zone training. While balance is often key, adjusting the amount of higher or lower intensities can help your efficiency.
I Keep Hearing About Zone 2 Training. Why is it So Special?
You might have heard the phrase “If you want to run fast, you have to run slow”. It sounds counterintuitive, but it’s one of the most effective principles in endurance training.
Zone 2 training at 60-70% of your maximum heart rate is the foundation for improving speed, endurance, and overall fitness.
1. Build a Strong Aerobic Base
Think of your aerobic system as the engine of a car. The bigger and more efficient the engine, the faster and farther you can go without breaking down. Zone 2 training enhances your body’s ability to use oxygen efficiently, burn fat for fuel, and sustain effort for longer.
Elite runners and endurance athletes spend up to 80% of their training in Zone 2 because it strengthens their aerobic foundation, allowing them to handle higher-intensity efforts more effectively.
2. Improve Fat Utilization and Energy Efficiency
In Zone 2, your body learns to rely more on fat as a fuel source instead of carbohydrates. This is crucial because fat provides a nearly unlimited energy supply, whereas carbs run out quickly.
Why does this matter? If your body burns fat efficiently, you can sustain exercise for longer periods without hitting “the wall” (when you run out of glycogen). This translates to improved endurance and faster race times over time.
3. Increases Capillary Density and Mitochondrial Growth
Zone 2 training stimulates your body to build more capillaries (small blood vessels) and mitochondria (your cells’ energy powerhouses). This means:
- More oxygen is delivered to your muscles.
- Greater endurance and faster recovery.
- Better ability to clear waste products like lactate, delaying fatigue.
Over time, this leads to greater speed and stamina without the need to train at maximum effort every day.
4. Allows You to Handle Higher-Intensity Workouts Better
Zone 2 training isn’t about avoiding speed; it’s about building a base so you can handle speed work more effectively.
Elite athletes train in Zone 2 so they can push harder on their fast days. Their easy runs allow for proper recovery, which means their sprint, interval, and threshold sessions are more productive.
If you train hard every day, your body never fully recovers, and your speed sessions suffer. But if you build a solid aerobic base with Zone 2 work, your legs will feel fresher and stronger on the days you do need to run fast.
Which is the Best Heart Rate Zone?
It depends! Sorry, we know this is one of the most frustrating answers that seems to appear time and time again when it comes to figuring out your health and fitness. But lets see if we can unpick that a bit further and help you find the answer you need, based on your goals.
How to Start Heart Rate Zone Training for Fat Loss
While zone 2, the ‘fat-burning zone’, sounds ideal, relying on it exclusively isn’t always the most efficient strategy for fat loss. Fat loss ultimately comes down to your overall energy balance, burning more calories than you consume, so incorporating both steady-state cardio and high-intensity workouts as well as nailing your nutrition actually creates the best results.
1. Zone 2 Training for Steady Fat Burn
Performing low-to-moderate intensity workouts for 30-60 minutes several times per week helps your body build endurance while utilising fat as its primary energy source. Great examples include walking, light jogging, swimming or cycling.
2. High-Intensity Workouts for Maximum Calorie Burn
High-intensity interval training (HIIT) alternates between short bursts of intense effort and periods of rest or lower-intensity movement. These workouts can last 20-30 minutes and burn calories more efficiently due to the afterburn effect, where your metabolism remains elevated even after you finish exercising.
3. Strength Training to Boost Metabolism
Adding strength training helps build lean muscle, which in turn increases your resting metabolism. The more muscle you have, the more calories your body burns throughout the day, even when you’re not working out.
Finding the Right Balance
The best approach to fat loss combines both heart rate zones strategically. A well-balanced week of training might include:
- 2-3 days of Zone 2 cardio (walking, jogging, cycling)
- 2-3 days of high-intensity workouts (HIIT, interval training, strength sessions)
- At least 1 day of active recovery (light stretching, yoga, or an easy walk)
How to Start Heart Rate Zone Training for Endurance
During Zones 2 and 3, your body learns to sustain effort over time while efficiently using oxygen and energy stores. These are definitely the key zones to focus on.
Zone 2: The Foundation of Endurance
Often referred to as the “aerobic base” zone, Zone 2 training keeps your heart rate at around 60–70% of your maximum heart rate. At this intensity, you can hold a conversation without gasping for breath. It might feel deceptively easy, but the benefits are massive: your body becomes better at burning fat for fuel, your mitochondria (the powerhouses of your cells) become more efficient, and your endurance capacity increases. Long, steady efforts in Zone 2, whether it’s a long run, ride, or row, help build the stamina you need for sustained performance.
Zone 3: Pushing the Threshold
Zone 3 (70–80% of max heart rate) is where things get a little tougher. This is often called the “tempo zone” because it sits just below your lactate threshold, the point where your body starts accumulating fatigue more quickly. Training in this zone improves your ability to sustain a faster pace for longer periods. It’s a great way to bridge the gap between endurance and speed, strengthening both your cardiovascular system and muscular endurance. Workouts in this zone usually involve moderately hard, sustained efforts, like tempo runs or steady-state cycling.
Zone 5: The Secret Sauce
While endurance athletes spend most of their time in Zones 2 and 3, some training in higher zones can be beneficial for speed and power:
- Improves VO2 Max – Short, intense efforts push your cardiovascular system to its limits, increasing your maximum oxygen uptake (VO2 max). A higher VO2 max means your body can deliver more oxygen to working muscles, improving endurance efficiency.
- Boosts Speed & Power – Even for endurance athletes, having the ability to generate bursts of speed can be useful, whether for surging ahead in a race or tackling hills with more ease.
- Increases Lactate Tolerance – Zone 5 efforts help your body clear lactate more efficiently, allowing you to sustain higher intensities for longer before fatigue sets in.
How Much Zone 5 is Necessary?
Since Zone 5 is extremely taxing, it should be used sparingly, typically no more than 5-10% of total training time.
Workouts like high-intensity interval training (HIIT), hill sprints, or short bursts on the bike can be incorporated once or twice a week to complement lower-intensity endurance work.
If your primary goal is endurance, Zone 5 training should support, not replace, your steady-state and tempo work. Think of it as the finishing touch rather than the foundation of your program.
How to Start Heart Rate Zone Training for Overall Fitness
Using heart rate zones is an effective way to improve general fitness by incorporating a mix of zones into your routine. For example, a workout might involve warming up in Zone 1 and then spending the majority of your time in Zone 2 or 3 to build endurance. You can add higher-intensity intervals in Zone 4 or 5 to push your limits and finish with some recovery time in Zone 1. This variation in intensity keeps your body challenged and helps you make consistent progress.
As you continue to train and improve your fitness, you’ll notice that you’re able to maintain higher heart rates for longer periods without feeling as fatigued. This is a clear sign that your cardiovascular system is becoming more efficient, and your overall fitness level is improving.
There’s no one fixed way to approach a balanced range of heart rate zone training, but to get you started, find an example week of heart rate zone training below.
Day 1: Low-Intensity (Zone 2 & Zone 1)
- Focus: Endurance
- Spend 40-60 minutes in Zone 2 (60-70% MHR)
- 5-10 minutes warm-up/cool-down in Zone 1 (50-60% MHR)
Day 2: Moderate-Intensity (Zone 3)
- Focus: Aerobic fitness and stamina
- Spend 30-45 minutes in Zone 3 (70-80% MHR)
- Light warm-up/cool-down in Zone 1
Day 3: High-Intensity (Zone 4 & Zone 5)
- Focus: Speed, power, and strength
- 20-30 minutes of HIIT or sprints, spending 10-20% of time in Zone 4 (80-90% MHR) and 5-10% in Zone 5 (90-100% MHR)
Day 4: Active Recovery (Zone 1 & Zone 2)
- Focus: Recovery
- Spend 20-30 minutes in Zone 1 (50-60% MHR), with 10-20 minutes in Zone 2 (60-70% MHR)
- Light activity like walking or gentle yoga
Day 5: Low-Intensity (Zone 2 & Zone 1)
- Focus: Endurance and active recovery
- Spend 40-60 minutes in Zone 2 (60-70% MHR)
- 5-10 minutes warm-up/cool-down in Zone 1
Day 6: High-Intensity (Zone 4 & Zone 5)
- Focus: Speed, power, and strength
- 20-30 minutes of HIIT or explosive sprints, with 10-20% in Zone 4 and 5-10% in Zone 5
Day 7: Rest or Active Recovery
- Focus: Complete rest or light movement
- If active recovery, spend time in Zone 1 or light Zone 2 for 20-30 minutes
This structure ensures a mix of endurance, power, and recovery while preventing overtraining. Adjust intensity based on your fitness level and goals.
Are Heart Rates The Only Thing We Should Focus On?
While our zones can give us important data about our fitness and progress, there are some nuances to take into consideration.
Heart Rate Zones in Different Sports
As Polar explains, “There is some fluctuation in heart rate zones depending on the sport. For example, take cycling and running on the same level of intensity: the cyclist’s heart rate is 5-10 beats slower than the runner’s. This is because cyclists don’t need to support their own bodyweight and their muscles can use most of the available oxygen for moving forward. Also, the number of working muscle groups is smaller in cycling. In swimming heart rate is even lower, usually about 5 beats below cycling.”
That means you may need to adjust the intensity depending on the form of exercise to keep you in the target zone.
Lifestyle Factors Have an Impact Too
Caffeine is a stimulant that can increase heart rate by boosting adrenaline levels. This may cause your heart rate to be higher than expected during a workout, potentially pushing you into a higher heart rate zone. This can make it harder to stay within a specific heart rate zone for training purposes. It’s also worth noting that caffeine affects people differently, so some may feel its impact more than others.
Dehydration can cause your heart rate to increase, as your body works harder to pump blood and maintain oxygen delivery. It can also make it harder to recover during workouts. Staying hydrated helps you stay within the desired heart rate zone
Mental or emotional stress can elevate your heart rate, even before a workout begins. If you’re stressed, you may find it harder to keep your heart rate within the target zone, especially during intense exercise.
Heat and humidity can cause an increase in heart rate, as the body works to cool itself down. Working out in warmer environments may push your heart rate into a higher zone.
Poor or insufficient sleep can elevate resting heart rate, making it harder to stay within your desired heart rate zone during exercise. Well-rested individuals tend to have a lower resting heart rate and more efficient cardiovascular systems.
Your fitness level can have an impact too. More conditioned individuals often have lower resting heart rates and may find it easier to remain in a specific heart rate zone during training. Beginners or those less conditioned may experience higher heart rates more quickly, especially at lower intensities.
As you age, your maximum heart rate decreases, which can affect your target heart rate zones. This is something to keep in mind when training older clients or individuals.
Time to train!
Now you’re armed with all the tools on how to start heart rate zone training and progress efficiently towards your goals, it’s time to start hitting those zones!
If you missed part 1 which explains what the different zones are, you can read that here.
