Find Your Max Heart Rate and Use It to Know Your Training Zones
If you've ever looked at a running plan and seen instructions like "Run for 45 minutes in Zone 2" or "Complete 5 x 5 minutes in Zone 4," you may have wondered:
How do I know what my zones actually are?
Knowing your heart rate zones allows you to train with purpose instead of simply running based on how you feel. Whether your goal is to finish your first 5K, improve your marathon time, or tackle an ultramarathon, understanding your heart rate can help you recover better, train smarter, and reduce your risk of overtraining.
What is Maximum Heart Rate?
Your Maximum Heart Rate (HRmax) is the fastest your heart can safely beat during maximal exercise.
It isn't something you can maintain for very long—usually only a few seconds at the end of an all-out effort—but it serves as the foundation for calculating your training zones.
Many watches estimate your maximum heart rate automatically, but these estimates are often inaccurate because everyone's physiology is different.
The Problem with the common "220 - Age" Formula
Many people have heard the equation:
220 - your age = Maximum Heart Rate
For a 35-year-old, that predicts a maximum heart rate of 185 bpm.
While simple, this equation was never designed to prescribe individual training. Research has shown that actual maximum heart rates can vary by 10-20 beats per minute or more between people of the same age.
Imagine two runners who are both 35 years old:
Runner A has an actual HRmax of 175 bpm
Runner B has an actual HRmax of 198 bpm
If both use 185 bpm as their maximum, their training zones will be significantly off. One may train much harder than intended, while the other never reaches the intensity needed to improve.
That's why finding your own maximum heart rate is far more valuable than relying on a generic formula.
For myself personally, at 37, my theoretical max hr would be 183, but I can hold that for a half marathon, and during a triathlon last year I reached 201 BPM (on my watch)
How to Find Your Maximum Heart Rate
Before attempting any maximal effort, make sure you are healthy enough for vigorous exercise. If you have cardiovascular concerns or medical conditions, consult your healthcare provider first. If you have a very reduced level of fitness or compromised health, a max-level effort test can be problematic.
Option 1: Field Test (Recommended)
This is the method I recommend for most runners.
Step 1: Warm up for 10-15 minutes with easy running.
Step 2: Run 3 minutes at a hard but sustainable pace.
Step 3: Recover for 2 minutes with easy jogging.
Step 4: Run another 3 minutes, starting hard and finishing with everything you have left during the final minute.
Your highest recorded heart rate during that final push is a good estimate of your maximum heart rate.
Option 2: Hill Repeat Test
Find a hill that takes approximately 2-3 minutes to climb.
Step 1: Warm up thoroughly. Walk up the hill a few times or 10-15 minute run
Step 2: Complete one hard climb.
Step 3: Jog back down.
Step 4: Repeat 1-2 more times, increasing your effort each time.
Step 5: During the final climb, sprint the last 20-30 seconds.
The highest heart rate reached is typically close to your HRmax.
Understanding Your Training Zones
Once you know your maximum heart rate, you can build personalized training zones.
Zone 1= 50-60% Recovery and easy movement
Zone 2= 60-70% Aerobic endurance and long easy runs
Zone 3= 70-80% Moderate endurance and steady efforts
Zone 4= 80-90% Threshold training and sustained hard efforts
Zone 5= 90-100% VO₂ max intervals and maximal efforts
What Each Zone Does
Zone 1 – Recovery
This is where recovery happens.
Easy recovery runs increase blood flow, reduce soreness, and help prepare you for your next quality workout.
Zone 2 – Build Your Engine
This is arguably the most important zone for endurance athletes. It’s low enough intensity to recover from very quickly, but provides enough stress to drive adaptation.
Running in Zone 2 develops:
Aerobic capacity
Fat-burning efficiency
Capillary density
Mitochondrial function
Long-term endurance
Most successful distance runners spend the majority of their weekly mileage here. especially when building to or maintianing high volume.
Zone 3 – The "Grey Zone"
Zone 3 isn't inherently bad, but it's often overused.
It's hard enough to generate fatigue but usually not hard enough to maximize fitness gains compared to dedicated threshold workouts.
Many recreational runners accidentally spend most of their training in this zone.
This zone is typically going to be your race pace for something like a half marathon or longer.
Zone 4 – Raise Your Threshold
Threshold workouts improve your ability to maintain faster paces for longer periods.
This includes running at high effort for longer intervals (up to 40 minutes)
This is where your body becomes better at clearing lactate and delaying fatigue.
Zone 5 – Maximum Effort
Zone 5 develops your top-end aerobic capacity and running speed.
These workouts should be performed sparingly because they are extremely demanding and require adequate recovery.
Do You Need to Stay Exactly in the Zone?
Not necessarily.
Heart rate naturally changes because of:
Heat
Hills
Hydration
Fatigue
Stress
Caffeine
Sleep quality
Think of your heart rate zones as guides rather than rigid rules. Combining heart rate with perceived effort and pace provides the most complete picture of your training.
The Bottom Line
Heart rate training helps remove the guesswork from running.
Instead of asking, "Am I running too hard?" you'll know.
Instead of making every run feel like a race, you'll understand when to push and when to back off.
Finding your true maximum heart rate is one of the simplest ways to make your training more effective, whether you're preparing for your first 10K or your next ultramarathon.
Need Help Building a Personalized Running Plan?
At Phase One Performance, I help runners of all experience levels Get Stronger, Move Faster, and Last Longer.
Every goal has a starting point—and understanding your heart rate is a great place to begin.
