In addition to what p22 said, which is for the right on the money (though you can do cardio right in the morning) to find your max heart rate, you need to subtract your age from 220. (226 if you are a woman). Now based on this number you can train at different heart rate percentages for different training effects. The 50-60% zone is low intense but 85% of calories will come from fat... which is good. 60-70 is similar but you will burn more calories, again 85% from fat. 70-80 is good for endurance and heart health with only 50 percent of calories coming from fat. 80-90 is highly intense, catabolic, and 15 percent coming from fat. Maybe next time the machine asks you to grip the handles for proper heart rate, you won't tell it to fuck off.