Author: Dr Cal Shields MBChB LLM MPhil MRCS (ENT) | Longevity and Aesthetics Doctor
What is Zone 2 Exercise and How to Get Your Heart Rate There
Zone 2 training is one of those concepts that sounds simple but often gets overcomplicated. At its core, Zone 2 is moderate-intensity aerobic exercise where your heart rate sits at 60-70% of your maximum. It feels easy. You can hold a conversation. And that simplicity is exactly why it works.
What is Zone 2?
Zone 2 refers to the second of five heart rate training zones. It is characterised by steady, sustainable effort where your body primarily burns fat for fuel rather than carbohydrates. During Zone 2 exercise, you should feel like you could continue for an hour or more without significant fatigue.
The simplest test is the talk test. If you can speak in full sentences without gasping for breath, you are likely in Zone 2. If you can only manage a few words, you have pushed into Zone 3 or higher.
How to Calculate Your Zone 2 Heart Rate
The most common method uses this formula: 220 minus your age gives your estimated maximum heart rate. Multiply that by 0.60 and 0.70 to get your Zone 2 range.
Example for a 40-year-old:
- Maximum heart rate: 220 – 40 = 180 bpm
- Zone 2 lower limit: 180 × 0.60 = 108 bpm
- Zone 2 upper limit: 180 × 0.70 = 126 bpm
This means a 40-year-old should aim for 108-126 beats per minute during Zone 2 training.
However, individual variation is significant. A 2025 study of 50 cyclists found that Zone 2 markers vary by 6-29% between individuals when using standardised percentages of maximum heart rate. The researchers concluded that personalised Zone 2 prescriptions based on physiological measurements may provide a more accurate approach than generic formulas.
If you do not have a heart rate monitor, the talk test remains a reliable guide.
The Science: What Happens in Zone 2
At Zone 2 intensity, your body operates primarily on aerobic metabolism. This means your muscles use oxygen to break down fat for energy, sparing your glycogen stores for higher-intensity efforts.
Two key adaptations occur with consistent Zone 2 training:
Fat oxidation improves. Your body becomes more efficient at using fat as fuel, which is particularly valuable for endurance activities and metabolic health.
Mitochondrial function increases. Mitochondria are the structures inside your cells that produce energy. Zone 2 training stimulates them to work more efficiently, though this effect is more pronounced with sessions lasting 60-90 minutes.
Research on triathletes found that athletes who spent more than 20% of their training time in Zone 2 showed significantly greater improvements in aerobic capacity. The high-Zone 2 group dedicated 24.7% of their training to this zone, compared to 11.8% in the low-Zone 2 group.
Benefits of Zone 2 Training
Builds your aerobic base. Zone 2 develops the foundation that supports all other training. A stronger aerobic base means you can sustain harder efforts for longer.
Enhances fat metabolism. Training at this intensity teaches your body to burn fat more effectively, preserving carbohydrate stores for when you need them.
Supports recovery. Zone 2 sessions place less stress on your muscles and joints than higher-intensity work. They can be used as active recovery between harder training days.
Reduces injury risk. The lower intensity means less mechanical stress, making it a sustainable option for consistent training.
Improves cardiovascular health. Regular aerobic exercise strengthens your heart and improves circulation, with benefits extending beyond athletic performance.
How to Apply Zone 2 Training
Choose your activity. Zone 2 works with any cardiovascular exercise: walking, jogging, cycling, swimming, rowing, or using an elliptical. The key is maintaining your target heart rate.
Start with 30 minutes. If you are new to structured training, begin with 30-minute sessions two to three times per week.
Progress to 60-90 minutes. Longer sessions maximise the mitochondrial and fat-burning benefits. Aim for at least one longer Zone 2 session each week.
Use the 80-20 rule. Many endurance athletes spend approximately 80% of their training time at low intensity (Zones 1-2) and 20% at higher intensities. This polarised approach builds a strong aerobic base whilst still developing speed and power.
Be patient. Zone 2 adaptations take time. Expect noticeable improvements after 6-8 weeks of consistent training.
Conclusion
Zone 2 training is straightforward: exercise at 60-70% of your maximum heart rate, or at an intensity where you can comfortably hold a conversation. The science supports its value for building aerobic capacity, improving fat metabolism, and supporting long-term health.
Calculate your personal Zone 2 range using the 220-age formula, then choose activities you enjoy. Start with 30 minutes and progress towards longer sessions as your fitness improves. Be consistent, be patient, and let the adaptations build over time.
Zone 2 may not be glamorous, but it works.
Don’t just live – Thriyv
