You’ll often read that your target heart rate (HR) should be 60 to 80 percent of your maximum HR when you exercise. And, to reap the health benefits of cardiovascular exercise, your training plan should include a goal of three to five workouts per week, lasting 20 to 60 minutes (not including warm-ups).

Although athletes often exceed the 60-80 percent target for increased stamina, the average person gains little additional value when exceeding this range. Exceeding the target range places undue stress on your body and increases your potential for injury. Your heart is simply working too fast and your body is having a hard time replenishing oxygen. On the other hand, exercising below the 60 percent goal has fewer benefits for those who exercise regularly.

So yes, heart rate monitors are useful tools for those interested in maximizing their results in the shortest possible time. They are especially useful for endurance athletes and those interested in losing weight. Keeping your HR within the target range allows you to exercise for longer periods of time without depleting your body’s resources and achieving maximum benefits during your workout.

Typical Heart Rate Zones

• Heating (50 – 60% of max heart rate): The right zone for people just starting an exercise program and a good warm-up zone for those who exercise regularly. This zone has many benefits and a low risk of injury. It also helps you reduce body fat, blood pressure, and cholesterol levels; it is estimated that 85% of the calories burned in this zone come from body fat.
• gentle exercise zone (60 – 70% of maximum heart rate): This zone offers basically the same benefits as the warm-up zone, except that it burns more calories due to the higher level of exercise.
• aerobic zone (70 – 80% of maximum heart rate): The aerobic zone will improve your cardiovascular and respiratory system and strengthen your heart. This zone is preferred by endurance athletes and those interested in significantly improving their fitness level.
• anaerobic zone (80 – 90% of maximum heart rate): Endurance athletes benefit from training in this zone. This zone helps improve your VO2 max: the highest amount of oxygen one can consume during exercise. Your doctor or a high-level gym can test your VO2 max. It takes more than measuring your heart rate while running on a treadmill; the specialized equipment you breathe into while exercising is the best way to measure it. Exercising in the anaerobic zone also improves your endurance levels by increasing your lactate tolerance (you fight fatigue better). This is a high intensity zone. Only include it in your training if you know what you’re doing and have your doctor’s approval.
• HR max (90 – 100% of max): Consult a doctor before creating a training plan that includes exercises to reach maximum heart rate. Although this zone is achievable and you will burn a lot of calories, most people, even those in excellent shape, will only exercise in this intense zone for very short periods of time.

Here’s a nice little tool to estimate your target heart rate: Calculate Target Heart Rate