Exercise intensity can be gauged based on this simple equation:

220- (minus) your age gives you a fairly accurate estimate of your maximum heart rate.

Heart rate is used as a benchmark in determining exercise intensity because as the exercise gets more difficult, the heart has to provide the working muscles with more blood, which means the heart has to pump faster. Working at a maximum intensity is very uncomfortable to exercise at and is most suitable for athletes. For the general population, a healthy exercises range is 60-80% of you maximum heart rate. To find this rate, take your max heart rate and multiply it by .6 and .8 respectively to get your exercise range.

You exercise range can be further broken down into moderate and vigorous zones. If you are looking to improve your cardiovascular fitness over time, then incorporating small bouts of vigorous physical activity into your daily routine can help. Start small; 2 minutes and work up. As you become more fit, it will take more intense exercise to get you in the vigorous zone. Eventually you will be able to enjoy more vigorous physical activity pursuits.

There are several ways to know what intensity you are working at: the heart rate equation, and/or how you feel. Moderate exercise is characterized by an increased heart rate, increased rate of breathing, mild sweating and the ability to carry on a conversation while exercising. If you find you cannot carry on a conversation, then you are working too hard. You can also use a scale from 1 to 10. If the exercise you are doing feels like a 6-7 then you are in the moderate zone.