If you goal is to race at a certain pace, then your training should revolve around doing that - getting you ready to race at that pace or level of intensity. A HRM can be of some asisstence in this regard, but a program of training that revolves completely around what your HRM says has some serious flaws in it.
Strange thing is that you seldom see the top ranked runners in the world standing on the side of the road or track checking their pulse with a HRM!
Training "hard" all year around is not a wise thing either. However, relativly speaking, the top endurance sport athletes in the world are not that far away from their fitness peak for much of the year. They will be running, skiing, cycling, swimming, whatever, close to world class times pretty much all year round. They dose their training with a decent amount of quality training all year round. This is one lesson that does transfer well to masters and age-group athletes - why? We don't have the time to build up a huge aerobic base of miles, so the answer is to not get that far away from top level fitness, once established, by dosing the training year round with a decent amount of quality.
Steve Fleck @stevefleck | Blog