Sometimes we spend over thirty minutes running on a treadmill, then add 10 more minutes in the cross trainer, then you are completely exhausted and need to leave the gym because you feel you are done with your workout. The truth is that if you don't know your target heart rate and you are exceeding your maximum heart rate during a tough cardiovascular session you may be either wasting your time because if you go bellow your target heart rate you won't burn enough calories and if you go above and beyond your your maximum heart rate you may be burning muscle instead of fat. So in order to have a productive workout where you burn a good amount of calories and get rid of fat not lean muscle you need to find out what your target heart rate is. I visited this website and found the Target Heart Rate calculator to be easy to use the and free of annoying advertisement www.stevenscreek.com/goodies/hr.shtml
Remember to post your questions!
Have a fun workout :)