Why is heart rate important?
If you want to train effectively you need to know your heart rate training zone. If you want to know how fit you are, a valid heart rate measurement is required. If you want accurate energy expenditure, you need an accurate heart rate measurement first.If you want to understand if you're training too hard you need to know what your training heart rate stress load is.
The MAF Method uses your heart rate as a critical indicator to keep you in your optimal training zone.