Bert Anderson: I wonder if you could enlighten me with your thoughts on Maximum Heart Rate (MHR) with regard to the percentage of MHR as used in your programmes in the Training Guide and the new six month BIRC programme [http://www.therowingcompany.com/birc/news.php?news=telsplan.inc].Does this mean 1) Absolute MHR (e.g. as in a max test, usually done on the treadmill, which since full bodyweight is carried usually gives the highest reading for most people)2) Rowing MHR (probably for the average person 5-10 beats below the above)3) Using the Karvonen formula to incorporate Resting Heart Rate in 1 or 2 These give four different MHR's which when used to work out percentage rates gives significant variation to the target zones.My own reasoning tends towards Rowing MHR incorporating RHR, but I would really appreciate your views on this.Terry O'Neill: You need to be careful when you talk about absolute maximum heart rate. You are right that you will achieve a higher heart rate on the treadmill than the rower but that does not mean it is the absolute maximum. In sporting terms when we refer to Heart Rate Maximum we mean the maximum that the activity will elicit. Use HRM obtained on the rower for rowing training, HRM on the treadmill for running training and HRM on the bicycle for cycling training.The real measure of the intensity of the training session is the lactate level. Because this is impossible for most people to measure during training sessions we use heart rate approximations to Lactate levels. Straight away you can see the problem, heart rate bands themselves are an approximation. When you add to this the fact that heart rate to lactate level change as a result of training and that individual heart rate at anaerobic threshold can range from 50% to 87% depending on fitness levels, you start to see why the figures are confusing. You can also ask why bother to add them in the first place. The answer is that from initially being aware of the fact that heart rate follows training loads, people start to ask the right sort of questions that will give a real personal guide to training intensities, something we cannot do from the outset when producing a training guide for all and sundry.Many people are aware of the formula 220 minus your age to get your MHR; this appears in the Polar Heart Rate Monitor information and has become universally accepted as a base line measurement, even though its origins are unclear and are not the result of any scientific study. Personally, I have always used heart rate range and MHR individually determined on the rowing machine. Another factor is whether you are training for an expressed purpose or exercising for general well being. In the first case then training intensities are very important as the programme will allow recovery time for adaptation to take place. If you are always training above the band then there may not be sufficient recovery time and instead of getting fitter you actually become run down.The lowest band-UT2, lactate levels should be no more that 2mm. Lactate will build up through the session so at the lower intensity you do not want the lactate to rise above the level set. Therefore if your heart rate at the lower intensity is on the low side of the band then this is OK. As you come up in intensity and you are actually looking to produce high lactate levels as part of the training aim then if you are on the high side of the heart rate band then this is OK.It's all very confusing but as long as you enjoy it that's the main thing.