You are here: Features > Smart Coaching Features > Heart Rate Zones

Heart Rate Zones

Your A300 uses Polar heart rate zones in training sessions that you've planned in the Flow web service and synced to your A300 as training targets.

Polar heart rate zones introduce a new level of effectiveness in heart rate-based training. Training is divided into five heart rate zones based on percentages of maximum heart rate. With heart rate zones, you can easily select and monitor training intensities.

Target zone Intensity % of HRmax

HRmax = Maximum heart rate (220-age).

Example: Heart rate zones (in beats per minute) for a 30-years-old person, whose maximum heart rate is 190 bpm (220–30). Example durations Training effect

90–100% 171–190 bpm less than 5 minutes Benefits: Maximal or near maximal effort for breathing and muscles.

Feels like: Very exhausting for breathing and muscles.

Recommended for: Very experienced and fit athletes. Short intervals only, usually in final preparation for short events.


80–90% 152–172 bpm 2–10 minutes Benefits: Increased ability to sustain high speed endurance.

Feels like: Causes muscular fatigue and heavy breathing.

Recommended for: Experienced athletes for year-round training, and for various durations. Becomes more important during pre competition season.


70–80% 133–152 bpm 10–40 minutes Benefits: Enhances general training pace, makes moderate intensity efforts easier and improves efficiency.

Feels like: Steady, controlled, fast breathing.

Recommended for: Athletes training for events, or looking for performance gains.


60–70% 114-133 bpm 40–80 minutes Benefits: Improves general base fitness, improves recovery and boosts metabolism.

Feels like: Comfortable and easy, low muscle and cardiovascular load.

Recommended for: Everybody for long training sessions during base training periods and for recovery exercises during competition season.


50–60% 104–114 bpm 20–40 minutes Benefits: Helps to warm up and cool down and assists recovery.

Feels like: Very easy, little strain.

Recommended for: For recovery and cool-down, throughout training season.

Training in heart rate zone 1 is done at a very low intensity. The main training principle is that performance improves when recovering after, and not only during training. Accelerate the recovery process with very light intensity training.

Training in heart rate zone 2 is for endurance training, an essential part of any training program. Training sessions in this zone are easy and aerobic. Long-duration training in this light zone results in effective energy expenditure. Progress will require persistence.

Aerobic power is enhanced in heart rate zone 3. The training intensity is higher than in sport zones 1 and 2, but still mainly aerobic. Training in sport zone 3 may, for example, consist of intervals followed by recovery. Training in this zone is especially effective for improving the efficiency of blood circulation in the heart and skeletal muscles.

If your goal is to compete at top potential, you will have to train in heart rate zones 4 and 5. In these zones, you exercise anaerobically in intervals of up to 10 minutes. The shorter the interval, the higher the intensity. Sufficient recovery between intervals is very important. The training pattern in zones 4 and 5 is designed to produce peak performance.

The Polar target heart rate zones can be personalized by using a laboratory measured HRmax value, or by taking a field test to measure the value yourself. When training in a target heart rate zone, try to make use of the entire zone. The mid-zone is a good target, but keeping your heart rate at that exact level all the time is not necessary. Heart rate gradually adjusts to training intensity. For instance, when crossing from heart rate target zone 1 to 3, the circulatory system and heart rate will adjust in 3-5 minutes.

Heart rate responds to training intensity depending on factors such as fitness and recovery levels, as well as environmental factors. It is important to look out for subjective feelings of fatigue, and to adjust your training program accordingly.