I think you answered my question right there Bruce. So the higher the heart rate the higher the intensity of the training - which at the right time would result in quicker improvement on the bike. Is that right? So could one say that in a race one wants the intensity at a lower heart rate but in order to achieve that one needs to train at a certain power at a higher heart rate so that the intensity of training is higher.Not quite There are a couple of problems with this approach: HR lags behind intensity, by up to a couple of minutes. So for intensities around pVO2Max HR is too slow to give a good guide to the intensity you are performing at. At lower intensities, HR is somewhat linearly related to intensity, but it is also impacted by hydration, fatigue levels, excitement levels, core body temperature, and other things. So it is a guide but it is impacted by lot's of other things, not just intensity. Above VO2Max, power is being produced by non-aerobic processes which do (by definition) not use oxygen and hence do not have the same effect on the heart. The training effect is produced by progressive overload. I.e. the body is subjected to incrementally more training dose, it responds to this dose, recovers to get stronger, and hence the dose can be increased. Training dose = intensity x volume. Now, since watts are a direct measure of intensity, the power you produce, for the time you produce it, is an exact measure of the training dose you have subjected your body to. By incrementally increasing this dose, positive training adaption occurs. HR is not really required in this process, it is just an overall indicator of how your body is responding to the intensity, it is not a measure of the intensity.
