The first zone is called the Healthy Heart Zone. This is 50-60% of your max heart rate. This is the easiest and most comfortable zone within which to train and is the one that is best for people who are just starting an exercise program or have low functional capacity. Those of you who are walkers most likely train at this zone. Although this zone has been criticized for not burning enough total calories, and for not being intense enough to get great cardio respiratory benefits, it has been shown to help decrease body fat, blood pressure, and cholesterol. It also decreases the risk of degenerative diseases and has a low risk of injury. In this zone, 10% of carbohydrates are “burned” (used as energy), 5% of protein is burned and a whopping 85% of fat is burned.
The next zone is the Fitness Zone, which is 60-70% of your max HR. Once again, 85% of your calories burned in this zone are fats, 5% are protiens and 10% are carbohydrates. Studies have shown that in this zone you can condition your fat mobilization (getting fat out of your cells) while conditioning your fat transportation (getting fat to muscles). Thus, in this zone, you are training your fat cells to increase the rate of fat release and training your muscles to burn fat. Therefore, the benefits of this zone are not only the same as the healthy heart zone training at 50-60% but you are now slightly increasing the total number of calories burned and provide a little more cardio respiratory benefits. You burn more total calories at this zone simply because it is more intense
The third zone, the Aerobic Zone, requires that you train at 70-80% of your max HR. This is the preferred zone if you are training for an endurance event. In this zone, your functional capacity will greatly improve and you can expect to increase the number and size of blood vessels, increase vital capacity and respiratory rate and achieve increases in pulmonary ventilation, as well as increases in arterial venous oxygen. Moreover, stroke volume (amount of blood pumped per heart beat) will increase, and your resting heart rate will decrease. What does all this mean? It means that your cardio vascular and respiratory system will improve and you will increase the size and strength of your heart. In this zone 50% of calories burned are from carbohydrates, 50% are from fat and less then 1% is from protein. And, because there is an increase in intensity, there is also an increase in total number of calories burned.