Mastering Endurance: How to Track and Optimize Zone 2 & VO2 Max Training (Part 3 of 3)
Part 3 of The Zone 2 Blueprint Series
In Part 1, we established why total weekly Zone 2 volume matters more than single long sessions for building endurance.
In Part 2, we explored how Zone 2 training supports VO2 max improvements and why adding high-intensity efforts can take your fitness to the next level.
Now, in Part 3, we’ll focus on how to structure a long-term endurance training plan and most importantly how to track your progress using modern tools like the Apple Watch, WHOOP, and Polar chest straps.
If you want to train smarter, not harder, you need the right balance of aerobic efficiency (Zone 2 work) and performance-enhancing intensity (VO2 max training) while ensuring you’re recovering properly.
How to Structure Your Training for Long-Term Endurance
A well-balanced training plan should focus on progressive overload, gradually increasing volume and intensity over time while allowing for adequate recovery. This principle is used when we lift weights, but often we don’t see our aerobic work as the same. Your heart is a muscle and it will adapt to the training protocols like muscles do.
So what does a good basic program look like.
Phase 1: Aerobic Base Building (4-6 weeks)
Goal: Develop a strong foundation using mostly Zone 2 training.
Why? This phase increases mitochondrial density, capillary growth, and fat oxidation, making your body more efficient at using oxygen.
Plan:
✅ 4–6 hours per week of Zone 2 (split across 4–6 days)
✅ One long session (75–90 min) per week
✅ Minimal high-intensity work (just strides or occasional hill sprints)
✅ Cross-training (optional) – cycling, swimming, or rowing
The Case for Longer, Slower, Cardio Training
Regular aerobic exercise has numerous benefits for overall health and wellbeing beyond weight loss. For years now, the Fitness Industry has been pushing the “High Intensity”, cram it in to a short time frame, Weight Loss toxicity down everyone’s throats. The industry has preyed and capitalized on human insecurities, and with great success.
Phase 2: Aerobic Base + VO2 Max Work (6-8 weeks)
Goal: Maintain aerobic efficiency while introducing structured VO2 max intervals.
Why? High-intensity work improves oxygen transport, cardiac output, and lactate clearance.
Plan:
✅ 3–4 Zone 2 sessions per week (totaling 3-5 hours)
✅ 1–2 VO2 max interval sessions per week
✅ One long Zone 2 session (90 min) per week
✅ Strength training (optional) – to support endurance and injury prevention
Best VO2 Max Workouts:
4x4 Intervals – 4 min hard (~90–95% max HR), 4 min recovery (repeat 4x)
5x3 Intervals – 3 min hard, 3 min recovery (repeat 5x)
30/30 Fartlek – 30 sec sprint, 30 sec easy (repeat 12–15x)
Take the guesswork out of training and get my 12 Week Zone 2 Training Program.
Phase 3: Performance Peak + Event-Specific Work (4-6 weeks)
Goal: Improve endurance at race pace or sustained effort levels.
Why? This phase improves fatigue resistance, pacing strategy, and mental endurance.
Plan:
✅ 1–2 race-specific intensity sessions per week (tempo runs, threshold work)
✅ 2–3 Zone 2 sessions per week for maintenance
✅ One long session (90+ min) per week
✅ Tapering and recovery focus in final weeks
Now that we have a general outline idea for what a 12 Week Training program might look like, it’s time to talk wearables for tracking.
How to Track Progress Using Wearables
Tracking your training is essential to ensure you’re actually improving and not overtraining. Here’s how to use popular tools like Apple Watch, WHOOP, and Polar chest straps effectively.
I personally use all 3 of these wearables for my training, depending on what I’m doing. My apple watch is on during the day and I usually use it to track various daily targets and goals. I also prefer to use it to track my workouts. I use it to track my runs in conjunction with my polar chest strap. My whoop is running 24/7 so it gives me a great overview on my entire day. There are now some great features that give me goals to set as well and just recently it began to calculate VO2 max using their algorithm.
Interested in Whoop? Try it and when you do, both you and I will get a free month… its a win win.
Apple Watch
✅ Tracks VO2 Max Estimates: The Apple Watch estimates VO2 max using GPS, heart rate, and motion data. However, it tends to underestimate VO2 max for trained athletes unless you regularly do max-effort runs. I compared the VO2 max data from Apple with my VO2 max test done in a clinic and they were close.
✅ Monitors HR in Zone 2: Use the Heart Rate app to ensure your sessions stay within 60-75% of max HR. - Only issue is that the Apple watch doesn’t adjust your zones as you become more fit.
✅ Tracks Recovery & HRV (Heart Rate Variability): Lower HRV over time = more stress, while higher HRV = better recovery
*Drawback is that the HRV calculation doesn’t include sleep data which is important information.
✅ Best for: General tracking, daily readiness, and cardio fitness estimates.
Pro Tip: Do a max-effort 5K run every 6-8 weeks to help the Apple Watch recalibrate your VO2 max estimate - I find that you have to run a max effort ever week to get the VO2 max on Apple Health to stay up.
WHOOP Strap
✅ Measures Recovery & Strain: WHOOP gives you daily strain scores based on HR, HRV, and sleep, which I think is super effective and probably more accurate than the watch if you aren’t wearing it to sleep. Also, watches are bulky. I often forget my Whoop is on.
✅ Tracks HR Zones Automatically: Great for confirming how much time you’re actually spending in Zone 2. A recent feature has been added that allows you to see your cumulative weekly time spent in zones as well as VO2 max data.
✅ Best for: Balancing training load and recovery ensuring you’re not overtraining.
Pro Tip: If WHOOP shows consistently low recovery scores, you may need more Zone 2 work and better sleep before adding intensity.
Polar Chest Strap (Polar H10, Verity Sense, etc.)
✅ Gold Standard for HR Accuracy: Chest straps are far more accurate than wrist-based sensors, especially for intervals and long sessions.
✅ Pairs with GPS Watches & Apps: Works with Garmin, Strava, Zwift, and Apple Health for precise HR tracking.
✅ Best for: Athletes who need precise HR data for Zone 2 & VO2 max training.
🔹 Pro Tip: Use a Polar chest strap for your VO2 max intervals to ensure you’re hitting 90-95% max HR for the right duration.
Common Mistakes That Can Sabotage Your Progress
🚫 1. Training Too Hard, Too Often
Many people push too hard on “easy” days and don’t go hard enough on “hard” days.
Solution: Stick to true Zone 2 on easy days it should feel comfortable and sustainable.
🚫 2. Ignoring Recovery
High-intensity training needs proper recovery without it, you risk burnout and injury.
Solution: Schedule at least 1 full rest day or active recovery session per week.
🚫 3. Skipping Long Sessions
Long efforts (75–120 min) train your body to use fat as fuel and improve endurance.
Solution: Prioritize one long effort per week even if at a slower pace.
🚫 4. Chasing VO2 Max Numbers Instead of Performance
A higher VO2 max doesn’t always mean better endurance performance efficiency matters more.
Solution: Focus on how comfortable you feel at a given pace/effort rather than just numbers.
Don’t waste energy and take the guesswork out of programming. Get my Zone 2 VO2 Max Training program today!
Final Thoughts: The Power of Patience & Consistency
Endurance training is a long game it takes weeks or months to see major improvements, but the benefits last a lifetime. The key is consistency, smart progression, and balancing Zone 2 with intensity.
Here’s your simple takeaway:
✔️ Most of your training should be in Zone 2 for efficiency and endurance.
✔️ VO2 max work is the icing on the cake use it sparingly but strategically.
✔️ Train smarter, not just harder balance effort and recovery.
✔️ Use wearables like Apple Watch, WHOOP, and Polar to track and adjust your training.
Whether you’re training for a race, longevity, or general fitness, using this structured approach will help you build a powerful aerobic engine for life.
Now it’s your turn get out there and start training smarter!
Sources & Further Reading
📚 Seiler, S. (2010). Best practices for training intensity and duration distribution in endurance athletes. International Journal of Sports Physiology & Performance.
📚 Murias, J. M., Kowalchuk, J. M., & Paterson, D. H. (2018). Mechanisms for increases in VO2 max with endurance training. Sports Medicine.
📚 Maffetone, P. (2014). The Big Book of Endurance Training and Racing.