Use this Calculator to determine approximate training intensity levels.  Keep in mind that these are only approximate levels.  Adjust the workout to how you feel, as your body will tell you if you are going too hard.  This calculator uses the Karvonen method to determine target zones, so you need to know your maximum heart rate in beats/min, also called MHR.  There are a couple of ways to find this.  The first is to have it done professionally on a treadmill, hooked

MAX Heart Rate Level     HR Range Level 1 Level 2 Level 3 Level 4 Level 5

up to an Electrocardiogram.  The second, if you are in good condition, is to one of the following sport specific tests.  Warm up for twenty minutes, while stretching, and wearing a heart rate monitor, do one of the following.  For Running and Cross-Country Skiing: Run for a mile, on a level surface, as fast as you can.  For the last 1/4 mile, run all out.  Then find your heart rate and this will be your max.  For Cycling: Use a stationary bike or an ergometer and ride as fast as you can for 5 minutes.  During the last 30 seconds ride all out, and then find your heart rate, and this is your max.  For Swimming: Swim 400 meters as fast as possible and go the last 50 all out, and then take your heart rate, and this is your max.  The third is to find your estimated MHR by subtracting your age from 220 for men, and 226 for women