The information provided here is believed to be accurate but not guaranteed. Please check with your doctor before starting any exercise program.

What percentage of maximum heart rate should you use? That depends on many factors. Different exercise programs specify different percentages. Longer duration exercise generally requires lower percentages. For example, for aerobic exercise people generally choose 50-80% of maximum heart rate. People just starting out may choose 50%, and for many people that is a good heart rate for warming up.
Short duration exercise is generally more intense. However, it can also depend on what kind of physical condition you are in and whether you have any physical conditions that could be dangerous with various types of exercise. This is why everyone should consult with a physician when starting a new exercise program!