Exercise Zones

Exercise zones are ranges between the lower and upper heart rate limits expressed as beats per minute (bpm) or as percentages of your maximum heart rate (HRmax). HRmax is the highest number of heartbeats per minute during maximum physical exertion.

Heart Rate Target Zones

Exercise can be divided into three different intensity zones. Each of these intensity levels corresponds to various health and fitness improving mechanisms in your body.

Light Intensity Zone

When your heart beats at 60-70% of your HRmax (HRmax %), you are in the Light Intensity Zone. Whether you have just started working out or you exercise fairly regularly, much of your workout will be in this zone. Fat is the body's main source of energy at this level of intensity; therefore this zone is also good for weight control. This intensity still feels fairly easy for most people and provides, for example, the following benefits:

  • Helps in weight control

  • Improves endurance

  • Improves aerobic fitness

Moderate Intensity Zone

Push on to 70-80% of your HRmax, and you are in the Moderate Intensity Zone. This is especially good for people who are exercising regularly. For most people, this is often the fastest pace they can maintain and still remain comfortable and free of pain. Exercising in this zone is particularly effective for improving aerobic (i.e. cardiovascular) fitness. If you are out of shape, your muscles will use carbohydrates for fuel when you are exercising in this zone. As you get fitter, your body starts using a higher and higher percentage of fat for fuel, thus preserving its limited stores of muscle carbohydrate. Exercising in the moderate intensity zone results in some additional benefits:

  • Improves aerobic fitness

  • Improves endurance

  • Helps in weight control

  • Accustoms your body to exercising at a faster pace

  • Begins to raise the speed you can maintain without building up lactic acid

Hard Intensity Zone

At 80-90% of your HRmax, you have moved into the Hard Intensity Zone. Exercise in the hard intensity zone definitely feels "hard". You will find yourself breathing heavily, having tired muscles and feeling fatigued. This intensity is recommended occasionally for fit people. Exercising in this zone is intensive, so it provides some unique benefits:

  • Increases muscles' tolerance to lactic acid

  • Improves hard, short effort ability

When you exercise in the correct intensity zones, it guarantees your enjoyment in your favorite sports. Alternate between intensity zones to improve your fitness and get variation in your exercise. Remember that the lower the intensity the longer you can comfortably exercise in it. Exercise in the higher intensity for shorter periods.

Note: Polar target heart rate intensity definition is modified from international exercise science authorities' recommendations in which light intensity can reach lower than 60% of HRmax.