Heart Rate Zone Training for Cardio Exercise

Pulse Monitor Fitness Watch

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Working out in a targeted heart rate zone can help make sure your workout is both safe and effective. Knowing how hard you need to exercise enables you to reach your goals more quickly. It also ensures that you don't push your body too much, making exercise unsafe.

Cardiovascular exercise relies on frequency, intensity, and duration to be effective. You know how often you exercise and for how long, but you need to know your heart rate to judge your intensity. Learn more about the effects of each of the five heart rate zones and how to use them in your cardio workouts.

Step 1: Determine Maximum Heart Rate

Once you learn your maximum heart rate (MHR), you can use heart zone training to gear your workout to the correct intensity. Your maximum heart rate is as fast as your heart can beat. This varies for each person, but age is generally used as a guide to estimate what your maximum heart rate is likely to be.

One of the easiest ways to determine your MHR is to subtract your age from 220. For instance, if you are 40 years old, your MHR is 180 (220 - 40 = 180).

You can also use the Tanaka formula, which is multiplying your age by 0.7, then subtracting that number from 208. So, for a 40-year-old, this calculation would also give an MHR of 180 (208 - (40 x 0.7) = 180).

A more individualized number can be provided through testing by a personal trainer or as a function of some of the more expensive heart rate monitors. You can also use an age-based heart rate chart to find your target heart rates based on percentages of your max.

Step 2: Determine Target Heart Rate Zones

You can get different fitness benefits by exercising in different heart rate (HR) zones. These five exercise zones are based on the percentage ranges of maximum heart rate. In each zone, you will feel a different level of exertion and your body will be burning a different percentage of carbohydrates, protein, and fat.

Very Light: Under 57% of MHR

This heart rate zone represents when you are sedentary or engaged in very gentle activity. Your ability to talk is not hindered at all but you're also not going to get the same level of calorie burn that you'll have with some of the higher heart rate zones.

Training within the very light heart rate zone is beneficial if you're recovering from a more intense exercise session or after participating in a grueling event. Exercises that are likely to place you in this zone include light walking or cycling on a flat terrain.

Light: 57% to 63% of MHR

The light heart rate zone is 57% to 63% 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 the light heart rate zone, the body derives 10% of its energy from burning carbohydrates, 5% from protein, and 85% from fat.

Walkers are often in this zone unless they press themselves to walk faster. If you exercise in higher heart rate zones, taking a walk in this zone is a good way to enjoy an easy recovery day while still being active.

Moderate: 64% to 76% of MHR

The moderate heart rate zone is from 64% to 76% of your maximum heart rate. This is the higher end of the moderate-intensity exercise zone. If using the talk test to measure your intensity, you will be breathing heavier but will still be able to speak in short sentences.

You burn more calories per minute than in the light 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 factor.

In the moderate heart rate zone, your body fuels itself with 10% carbohydrates, 5% protein, and 85% fat.

You get the same health benefits and fat-burning benefits as the light heart zone. An example of a workout in this zone is a brisk walking workout.

Vigorous: 77% to 95% of MHR

The vigorous heart rate zone is from 77% to 95% 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.

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.

In the vigorous zone, you burn 50% of your calories from carbohydrates, less than 1% from protein, and 50% from fat.

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.

When you train at the high end of this range (84% MHR or higher), this intense exercise will improve the amount of oxygen you can consume—your VO2 max. 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.

In the high end of the vigorous zone, the body burns 85% carbohydrates, less than 1% protein, and 15% fat.

Workouts in the higher end of this heart rate zone should be in the 10-20 minute range or part of an interval training workout.

Maximal: 96% to 100% of MHR

The top zone is from 96% to 100% 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, then repeat.

While you burn lots of calories per minute in the maximal zone, 90% of them are carbohydrates, less than 1% protein, and 10% fats.

You should consult with your doctor to ensure you can work out at such a high heart rate safely.

Step 3: Monitor Your Heart Rate During Exercise

Take your heart rate five minutes after the start of your exercise session and take it again before you go into your cool down. You can do this by taking your pulse, using a heart rate monitor, or using a fitness tracker or smart watch.

Take Your Pulse

You can find your pulse at your neck (carotid artery) or wrist (radial artery). You will need a timing device that shows seconds, so switch to stopwatch mode on your smartphone clock or use a watch, clock, or timer that has a second hand.

  • Use two fingers, and do not use your thumb as it has its own pulse. It is often easiest to find your pulse in the carotid arteries, which are on either side of your windpipe. Start feeling for it just beneath your jaw, next to your windpipe.
  • Once you locate the pulse, press lightly. Count your pulse for 10 seconds and multiply by six, or count for 15 seconds and multiply by four.
  • You may need to stop to do this at first, but once you are able to locate it, try to keep walking slowly or marching in place while taking your pulse to keep it from slowing.

Examples:

  • 20 beats for 10 seconds = 120 beats per minute
  • 20 beats for 15 seconds = 80 beats per minute

Your heart rate will slow if you stop moving, so it is important to check your pulse quickly if using the manual method,, counting for only 10–15 seconds.

Many treadmills and other exercise machines have grips with pulse sensors built in. You grip them and your pulse will read out on a display on the machine. You usually will not have to interrupt your workout to get a reading. You can also use a mobile app.

Use a Heart Rate Monitor

Heart rate monitors with a chest strap are more accurate than taking your pulse. They transmit the data to a wrist unit or a mobile app so you can see your heart rate throughout your workout.

As prices increase, models include many other features, such as tracking your heart rate zones, stopwatch features, calories burned, and more. Other kinds of heart rate monitors include pulse monitors where you place one or two fingers on a sensor for a reading.

Many heart rate monitors offer the ability to pre-program multiple heart rate zones. This is beneficial if you do a variety of different-intensity workouts because then you won't have to reprogram it each time. Some will even tell you how long it takes to return to your resting heart rate.

Use a Fitness Tracker or Smart Watch

Some fitness bands and smartwatches, such as some models of Fitbit and the Apple Watch, have LED pulse sensors on the underside next to the skin. These must be worn securely against the skin in order to get a stable and accurate reading.

To save battery life, many of them don't read continuously. See the instructions for your monitor or watch to see how to get an on-demand or continuous pulse reading.

These devices often have simplified heart rate zones, such as light, moderate, and vigorous. Some allow you to set a target heart rate and have a visual or auditory alert when you are in your chosen zone.

Vary Your Workouts

Which zone should you work out in? It is best to vary your workouts for length and intensity and allow a recovery day between days of intense exercise in the vigorous and maximal zones.

A training program will often have shorter workouts of higher intensity two to three days per week, alternating with a recovery/rest day. One day of a longer workout in the moderate or vigorous zone is often used to build mileage towards a race such as a 10K, half marathon, or marathon.

Racewalker Dave McGovern has a suggested weekly workout schedule that varies the workouts for intensity and heart rate to improve speed, endurance, and distance capacity:

  • Monday: Rest day with light activity
  • Tuesday: Interval workout in the vigorous zone with 10 minutes warmup at an easy pace; intervals of 30 seconds sprinting followed by two minutes of recovery, repeated eight to 12 times; then cool-down 10 minutes at an easy pace
  • Wednesday: Recovery day with a workout in the moderate zone for 30 to 45 minutes
  • Thursday: Interval workout in the vigorous zone with longer intervals of eight minutes at a vigorous intensity and two minutes of recovery, repeated three to four times
  • Friday: Recovery day with a workout in the moderate zone for 30 to 45 minutes
  • Saturday: Steady-state (tempo) workout in the low end of the vigorous zone for 20 to 30 minutes after a warmup of 10 minutes
  • Sunday: Distance workout in the low end of the vigorous heart rate zone
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