Ok this is a pretty big question with a lot of variables but basically...<br /><br />to work out your training zones there are two methods, the first is to go on a percentage of your max heart rate ie 60-75% of 206 for aerobic base rides, 75-85% for aerobic conditioning ie improving performance and 85-100% for really stretching your level of conditioning.<br /><br />This method works ok for people that don't train much however the values it gives tend to be a bit low for serious athletes.<br /><br />So the better way is to use the Karvonen formula to calculate zones, to do this you need to know your Max HR and your resting heart rate. Your resting heart rate is your heart rate taken after 5 mins of lying down but not sleeping (generally tested first thing in the morning as an average over three or four days)<br /><br />once you have your Max HR (MHR) and your Resting HR (RHR) you can calculate your heart rate reserve (HRR). HRR is your max minus your RHR<br /><br />your Karvonen levels are then worked out as percentage (65-75-85-100) times HRR + RHR<br /><br />then you can use these values to set your low medium and high zones.<br /><br />this generally gives you a higher HR training zone than the MHR times intensity calculation<br /><br />i would guess once you do the calculations that you will find that 145-150 is right at the bottom of your low level zone.<br /><br />As for when to use which zone, you will find that the low zone will allow you to ride for several hours without a problem and can be used for building your base endurance. the middle zone is good for rides up to an hour or so where you want to increase your ability to sustain aerobic effort and the top zone will improve your speed and lactic acid tolerance but you can't exercise in your top zone for very long so training in the top zone often takes the form of intervals<br /><br />if you have any more questions about this stuff email me or message me and i will get back to you, i'm just getting back to cycling but i've been a qualified personal trainer for ages and this stuff applies to all aerobic sports<br /><br />good luck with the training
