Having been trying to get up to date with my reading of back dated Newsletters, I was interested in Nick Butcher's letter in Issue 85 regarding establishing training bands based on the percentage of Heart Rate Range and the Resting Heart Rate; also the less than perfect formula of 220 minus a person's age and his query that a 'less fit person has to exercise at a higher heart rate than his/her fitter compadre'. Also his assumption that 'surely the fitter you are, the higher your comfortable, and therefore, effective range'. Firstly, arriving at one's Heart Rate Ranges by any of the above methods is not necessarily accurate to a fine degree and, of course, there is a wide working area within each band. As Terry O'Neill stated, it is not wise to compare one persons HR with another. There are far too many variables between people to equate one with another. From the individual's point of view the aim is to get the maximum result at the minimum cost. It is a mistake to assume that one's Maximum Heart Rate will increase with training; in fact, physiologically, the opposite is true! As pointed out in Terry's reply, the effect of training increases the stroke volume. This occurs obviously with the strengthening heart muscle and results in a greater output at a lower rate and a lower resting Heart Rate. Some of the other factors that contribute to this more efficient working at lower levels following training are those that influence the oxygen extraction between the arterio & venous AVO2, systems coupled with the massive increase in the capillary network throughout the muscles and tissues which allows more absorption of oxygen and dispersal of carbon dioxide. All these factors contribute to the ability to work at high outputs and lowest efforts possible. These improvements respond to specific types of training and not any form of work. Inevitably, the only accurate way of arriving at correct HR ranges is by taking a testing programme in a Sports Science Lab, but this is probably a step to far for most. Having said that, the 'Step Test' is a pretty good compromise and by transferring one's results to a graph, you can get a pretty good assessment of one's Anaerobic Threshold level, and from this arrive at the other levels.