The Energy Efficient or Recovery Zone - 50% to 60%
Training within this zone develops basic endurance and aerobic capacity. All easy recovery running should be completed at a maximum of 70 %. Another advantage to running in this zone is that while you are happily fat burning you may lose weight and you will be allowing your muscles to re-energies with glycogen, which has been expended during those faster paced work-outs.

The Temperate Zone - 60% to 70%
It's easily reached by going a little faster like increasing from a walk to a jog. While still a relatively low level of effort, this zone starts training your body to increase the rate of fat release from the cells to the muscles for fuel. Some people have erroneously called this the "fat burning zone" because up to 85 % of the total calories burned in this zone are fat calories. Rather, we burn fat in all zones.

The Aerobic Zone - 70% to 80%
Training in this zone will develop your cardiovascular system. The body's ability to transport oxygen to, and carbon dioxide away from, the working muscles can be developed and improved. As you become more fit and stronger from training in this zone it will be possible to train at up to 75%, so getting the benefits of some fat burning and improved aerobic capacity.

The Anaerobic or Threshold Zone - 80% to 90%
Training in this zone will develop your lactic acid system. In this zone your individual anaerobic threshold is found - sometimes referred to the point of deflection (POD). During these heart rates the amount of fat being utilized as the main source of energy is greatly reduced and glycogen stored in the muscle is predominantly used. One of the by-products of burning this glycogen, is the Athletes worst enemy, lactic acid. There is a point at which the body can no longer remove the lactic acid from the working muscles quickly enough. This happens at an individual heart rate for us all and is accompanied by a rapid rise in heart rate and a slowing of your pace. This is your anaerobic threshold or POD. Through the correct training it is possible to delay the POD by being able to increase your ability to deal with the lactic acid for a longer period of time or by pushing the POD higher.

The Red Line Zone 90% to 100%
Training in this zone will only be possible for short periods of time. It effectively trains your fast twitch muscle fibres and helps to develop speed. This zone is reserved for interval training and only the very fit are able to train effectively within this zone.

Age	Target Heart Rate (HR) Zone (60-85%)	Predicted Maximum Heart Rate
20	120-170	200
25	117-166	195
30	114-162	190
35	111-157	185
40	108-153	180
45	105-149	175
50	102-145	170
55	99-140	165
60	96-136	160
65	93-132	155
70	90-128	150
Your Actual Values	Target HR	Max. HR

As you become more fit your heart becomes more efficient at pumping blood around the body.
As a result you will find your resting heart rate gets lower so you will need to check your RHR on a regular basis (e.g. Monthly).

Resting Heart Rate
To determine your resting heart rate (RHR) is very easy. Find somewhere nice and quite, lie down and relax. Position a watch or clock where you can see the second hand. After 20 minutes remain where you are, do not sit up, and determine your pulse rate (beats/min). This is your RHR. If you have a heart rate monitor then put it on before you lie down. After the 20 minutes check the recordings and identify the lowest value achieved. This will be your RHR.

Target heart rate
You gain the most benefits and lessen the risks when you exercise in your target heart rate zone. Usually this is when your exercise heart rate (pulse) is 60 to 80 percent of your maximum heart rate. In some cases, your health care provider may decrease your target heart rate zone to begin with 50 percent.

Do not exercise above 85 percent of your maximum heart rate. This increases both cardiovascular and orthopedic risk and does not add any extra benefit.

Always check with your health care provider before starting an exercise program. Your health care provider can help you find a program and target heart rate zone that match your needs, goals and physical condition.

When beginning an exercise program, you may need to gradually build up to a level that is within your target heart rate zone, especially if you have not exercised regularly before. If the exercise feels too hard, slow down. You will reduce your risk of injury and enjoy the exercise more if you don't try to over-do it!

To find out if you are exercising in your target zone (between 60 and 80 percent of your maximum heart rate), stop exercising and check your pulse. If your pulse is below your target zone, increase your rate of exercise. If your pulse is above your target zone, decrease your rate of exercise.

Your goal should be 30-45 minute training sessions.
After 20 minutes, you will start burning more calories. Your body needs time to warm up -- pace yourself.