The theory behind the numbers:

When coaching my athletes, I use two protocols to determine their pace and heart rate zones.

The first is HRR (Heart Rate Reserve), which subtracts the "unusable" beats from the equation by taking into account your resting heart rate. This means your Zone 2 will often start at a higher heart rate than with other methods, making it a more realistic and achievable training zone for many runners.

The second is LTHR (Lactate Threshold Heart Rate), which is the heart rate at which your body begins producing lactate faster than it can efficiently clear it. This build-up contributes to fatigue and makes running progressively harder. Understanding how to use these heart rate and pace zones when planning an athlete's training is key to an efficient approach that balances performance gains with fatigue management.

You can use the calculator on this page to follow my approach and determine what your zones should be today. Remember, however, that as your fitness improves, or if your training takes a break, these numbers will change. It is important to reassess them regularly, ideally every 4-6 weeks during a structured training block.

For Garmin Users:

To find the data to input:

Ensure your device has auto-detection enabled:
On the Connect app, go to Settings > User Profile > Heart Rate & Power Zones > Auto Detection.
Perform a sustained, vigorous run.
Once the watch detects your threshold, a message will appear upon saving the activity saying your LTHR was updated.

To view your current LTHR and Pace.
On the App: select More (or the Menu) > Performance Stats > Running Lactate Threshold.

For your your Resting and Max HR.

Tap More (bottom right). Scroll down to Garmin Devices, select your watch, and tap User Profile > Heart Rate Zones > Max. HR.

If you're viewing this on a mobile, rotate your phone to landscape to see the full data set.