Exercise Intensity

When doing aerobic exercise, it is important to make sure that you are working hard enough. If you aren't reaching a certain level of intensity, you won't get the benefits of doing aerobic exercise, and as a result, you will not feel or see any of the related results.

Methods of Measuring Intensity

Target Heart Rate Zone*	What it does	Who Should be in this Range
55% - 65% of Maximum Heart Rate(MHR)**	Absolute minimum of where your heart rate should be in order to see cardiovascular benefits. Training in this zone will begin to improve your hearts' ability to pump blood and improve the muscle cells ability to utilize oxygen. This is a good zone for long slow distance exercise.	Those who are beginning an exercise regimen or are out of shape
65 - 75% of MHR	The "Aerobic Zone" or "Target Heart Rate Zone", it is the most effective for overall cardiovascular fitness. It increases your cardio-respiratory capacity (the body's ability to transport oxygenated blood to the muscle cells and carbon dioxide away from the cells). After a while you will be able to go longer in less time and your body will burn less glucose and more stored fat as fuel.	Those who are healthy and active and fall into an average level of fitness Those who are interested in health benefits and some aerobic training effects This zone is also effective for increasing overall muscle strength
75 - 85% of MHR	This zone often results in significant training effects in the heart, lungs and skeletal muscles, resulting in improved aerobic performance.	Individuals with an above average to high level of fitness Those looking to gain health benefits and improved aerobic exercise performance
85% - 90% of MHR	At this point you begin to cross over from aerobic training to anaerobic training (anaerobic threshold). At this point, the body cannot effectively remove lactic acid from the working muscles quickly enough. This zone is very difficult and your muscles become tired, your breathing becomes heavy and you become fatigued. The benefit of training in this zone is that you can increase your body's ability to tolerate and deal with lactic acid for a longer period of time.	This zone is primarily for people who want to increase their performance levels. Often competitors are highly in tune with this zone because they often compete near or at their anaerobic threshold
90 - 100% of MHR (VO2 Max)	In this zone, lactic acid develops very quickly because you are operating with oxygen debt to the muscles. You will not be able to stay at this level very long.	You should not train at this level unless you are extremely fit Often good for sprinters and those individuals who are looking to increase their fast twitch muscle fibers which increase speed

* To calculate your Target Heart Rate and Maximum Heart Rate, see the Target Heart Rate Calculations section above. Always check your pulse frequently throughout your workout to make sure you are within your target heart rate (THR) zone.

Use the following age based chart to quickly gauge where you fall within the target heart rate zones*. When exercising, take your pulse for 10 seconds.

* A more accurate guide factors in your resting heart rate. To calculate your individual heart rate, refer to the Karvonen Target Heart Rate Calculation.