Healthy Heart Zone
The healthy heart rate zone is 50 percent to 60 percent of your maximum heart rate. This is an easy and comfortable zone to exercise in. It’s considered to be the lower end of the moderate-intensity zone. You will be able to carry on a full conversation in this zone, although you may be breathing a little heavier than usual. Your workout in this zone is less intense and won’t give the most cardiorespiratory training benefits. But studies have shown that it works to help decrease body fat, blood pressure, and cholesterol. In this zone, the body derives its energy by burning 10 percent carbohydrates, 5 percent protein, and 85 percent fat. Walkers are often in this zone unless they press themselves to walk faster. If you exercise in higher heart rate zones, taking a healthy walk in this zone is a good way to enjoy an easy recovery day while still being active.
Fitness Heart Rate Zone
The fitness heart rate zone is from 60 percent to 70 percent of your maximum heart rate. This is the higher end of the moderate-intensity exercise zone. You will be breathing heavier but will still be able to speak in short sentences. You burn more calories per minute than in the healthy heart zone because the exercise is a little more intense. You are going faster and therefore covering more distance. The calories you burn depend on the distance you cover and your weight more than any other factors. In this zone, your body fuels itself with 85 percent fat, 5 percent protein, and 10 percent carbohydrate. You get the same health benefits and fat-burning benefits as the healthy heart zone. An example of a workout in this zone is a brisk walking workout.
Aerobic Heart Rate Zone
The aerobic heart rate zone is from 70 percent to 80 percent of your maximum heart rate. You are now in the vigorous-intensity zone. You will be breathing very hard and able only to speak in short phrases.
This is the zone to aim for when training for endurance. It spurs your body to improve your circulatory system by building new blood vessels and increases your heart and lung capacity. Aiming for 20 to 60 minutes in this zone is believed to give the best fitness training benefits. In the aerobic zone, you burn 50 percent of your calories from fat, 50 percent from carbohydrate, and less than 1 percent from protein. With the increase in intensity, you burn more calories in the same amount of time, as you are covering more distance in that same time. The calories you burn depend most on distance and your weight. If you go farther in the same amount of time, you burn more calories per minute. You would typically be in this zone by running or cycling, but you could achieve it by racewalking or walking fast for an aerobic walking workout.
Anaerobic Zone (Threshold Zone)
The anaerobic heart rate zone is 80 percent to 90 percent of your maximum heart rate. You will be unable to speak except a single, gasped word at a time. This intense exercise will improve the amount of oxygen you can consume—your VO2 maximum. This exertion level takes you to the limit where your body begins to produce lactic acid. Runners, cyclists, and racewalkers use this zone to build their ability to go even faster. Workouts in this heart rate zone should be in the 10-20 minute range or part of an interval training workout. You burn more calories per minute than with the lower heart rate workouts, as you are covering more distance per minute. The body burns 85 percent carbohydrates, 15 percent fat and less than 1 percent protein in this zone.
The top zone is from 90 percent to 100 percent of your maximum heart rate. You can’t go any higher, and most people can’t stay in this zone for more than a few minutes. You will be unable to speak except for gasping single words. This zone should only be used for short bursts during interval training, where you work intensely for a minute and then drop back down to a lower intensity for several minutes, and repeat. While you burn lots of calories per minute in this zone, 90 percent of them are carbohydrates, 10 percent fats, and less than 1 percent protein. You should consult with your doctor to ensure you can work out at such a high heart rate safely.
** Resource: Very Well Fit