To determine your threshold heart rate, you can use the average heart rate from a recent intense race or very hard interval training session where you were pushing yourself to the limit for 45-60 minutes. Alternatively, you can perform a 20-minute FTP (Functional Threshold Power) test and use the average heart rate during the last 15 minutes x 0.95 = Threshold heart rate. This will give you a good idea of your maximum effort level and help you gauge your intensity during future workouts.
Threshold heart rate
