Heart rate training is very effective for runners looking to build their endurance and race faster, especially in events of half marathon distance or longer. This plan is perfect for a runner that wants to take heart rate training for a test drive and is comfortable running 4 days per week. A few things to keep in mind as you kick the tires on heart rate training: ~Be patient! Progress with heart rate training, especially at first, can seem to be glacially slow. The longer you stick with it, ...