How does the personalised marathon heart rate training work? Will I need a heart rate monitor

Your personalised marathon heart rate is determined using your Anaerobic Threshold-point (AT-point) and your current fastest 10K time. You’ll perform a test to establish your AT-point, then use the provided charts to find your specific marathon heart rate based on these two factors. A heart rate monitor is essential for training at the correct intensity, so you’ll need to use one during your training runs.