How Much Cardio at the Maximum Heart Rate Is Needed for Weight Loss?

Cardio workouts are key to losing weight and the more intense your workout, the more calories you'll burn. Using this logic, it can be tempting to exercise as hard as possible in an effort to shed pounds quickly.

Unfortunately, working at your maximum heart rate is not only risky to your health, but can lead to frustration with your workout. Instead of focusing on going all out, aim to exercise regularly within a targeted intensity to lose weight and stay healthy.

Read more: Cardio Exercise Heart Rate

The intensity of cardiovascular exercise is often based on percentage of maximum heart rate. To calculate your maximum heart rate subtract your age from 220. For example, the maximum heart rate for a 40-year-old would be 180 beats per minute (220 - 40 = 180). Some factors, such as medications you're taking and coronary conditions, can affect maximum heart rate, and you should talk to your doctor about your exercise program.

Working at your maximum heart rate can cause physical and mental problems. First, regularly exercising at this intensely strains the heart muscle and can weaken the heart rather than improve it as cardiovascular exercise should do. Second, continually working this hard stresses your body and can lead to muscle and joint injuries. Waiting for these injuries to heal will keep you from exercising and slow your weight loss progress.

Another problem is the mental toll of intense exercise. Pushing yourself to the max day after day is tough. Even if you avoid injury or heart problems, you may become frustrated with trying to keep up with a super-intense regimen. Once you get frustrated, you may give up on working out altogether and won't meet your weight loss goals.

Read more: What Is a Good Exercise Heart Rate?

The American Heart Association recommends working out at an intensity that is 50 to 85 percent of your maximum heart rate. This is known as your target heart rate zone. When you first start a cardio program, you'll want to stay at the lower end of the zone. As you gain fitness, slowly increase the intensity to the higher end of the zone.

How intense you exercise will determine how long you need to exercise. The minimum amount of exercise adults need according to the Centers for Disease Control and Prevention is 150 minutes a week at a moderate intensity, or in the middle range of your target heart rate zone. If you can work vigorously at the upper end up your target heart rate zone, you only need to take 75 minutes of cardio exercise a week.

You can see weight loss results working at these levels, but to boost your weight loss, double the amount of time you work out: 300 minutes at a moderate intensity or 150 minutes at a vigorous intensity. To be safe, gradually increase your workout times and intensities.

Depending on your current weight and how hard you exercise, the calorie burn of the activities you choose for your cardio will vary. Cardio (or exercise in general) isn't just for weight loss. If weight loss is your goal, you need to create a "calorie" deficit of 3,500 calories to burn one pound of body fat. A calorie deficit means that your use more calories than you consume.

Exercising at a moderate intensity helps you create this calorie deficit. If you can burn off an extra 500 calories a day through exercise, you should lose one pound of fat in a week. If you boost your calorie deficit to 1000 calories a day through a combination of exercise and eating less, you could lose two pounds a week.

As long as you don't have any cardiovascular problems and you have your doctor's approval, you can use short bursts of high-intensity activities to improve your health and lose weight.

High-intensity interval training (HIIT) requires you to work at a moderate pace for two to three minutes and then work at a pace that pushes you above 80 percent of your maximum heart rate for one minute; for example, jogging for two minutes, then sprinting for one minute. This cycle is then repeated during the workout.

Because this is strenuous and requires both strength and endurance in the lower body, you need to build up the number of intervals you perform gradually and you should not do this type of workout two days in a row. HIIT can also contribute to post-workout calorie burn as the body recovers from the exercise.