This is one way to optimize the training and not to train with a too high or too low intensity. The schedule below applies for novice athletes. For competitive athletes the percentages should be adjusted.

If you want to train, guided by the heart rate, it is important to know where the individual heart rate zones are located. A heart rate zone is the area in which you train a specific part of the condition.

The determination of the correct zones can be based on the maximum heart rate (HR max).

HR max can be estimated: HR max = 220 – age

The HR max can also be determined by measurement. See the chapter on HR max.

There are five heart rate zones, which are calculated as a percentage of the maximum heart rate. Depending on the purpose of the training, you choose from one of the target zones below:

THE GREY ZONE: intensity very light (50-60% of HR max) – DAILY ACTIVITIES ZONE.

Target zone for the novice exerciser or someone with obesity. Examples of effort at this level are: walking, light aerobics, cycling and swimming. It is also the area for the recovery workout the day after a hard race or workout.

GREEN ZONE: EASY ENDURANCE TRAINING: intensity light (60-70% of maximum heart rate) – FITNESS ZONE.

This training is called: easy endurance training: EET Training in this zone is fully aerobic, the intensity of the workout is light and the duration of training is great. Also known as the ‘long slow distance training’ or LSD training. For improving your endurance and fitness, but it is also the ideal intensity for those who want to bring or keep their weight down.
Examples of activities include brisk walking, jogging, aerobics, cycling and swimming.

GREEN ZONE: INTENSIVE ENDURANCE TRAINING: intensity moderate (70 – 80% of maximum heart rate).

This training is called: intensive endurance training: IET. Training in this zone is almost totally aerobic. There is a slight increase in the content of lactate in the blood. The aerobic capacity increases. EET and IET may be alternated, in the same workout, in block form. Cycling training in the green area means a high pedaling frequency, RPM 90 – 100, in a training that is focused on the race distance. The overall endurance will improve. Examples activities include: jogging, running, cycling and swimming.

ORANGE ZONE: intensity hard (80-90% of maximum heart rate) – CONDITION ZONE.

Training in this zone is the so called tempo endurance training: TET. It is the transition zone from the green to the red zone. The effort is aerobic and more and more anaerobic. The intensity of a workout in this zone is hard. The cycling speed during this training is high. We also call this type of training the ‘big motor training’.
In this zone you improve the overall endurance. Examples of activities include: jogging, running, cycling, aerobics or swimming. Training in this zone mostly in blocks or intervals. Endurance and speed improves. Adequate recovery between intervals is essential.

RED ZONE: intensity maximum (90-100% of maximum heart rate) – PERFORMANCE ZONE.

At this level, the effort is anaerobic. The effort is so intense that the blood cannot carry enough oxygen to the muscles. The result is a build-up of lactic acid and tired and heavy legs. For beginners only once a week. Training in the red zone is the essence of performance. The red area is divided in resistance long and resistance short. Heart rate measurement in the red zone is as good as impossible because the exercise time is often too short for a good registration. The power meter works excellently in this area.

Target Zone Intensity % of HR max Example interval duration Physiological benefits Training effect
1. very light 50 -60 % 20 - 40 minutes Helps and speeds up recovery after heavier exertion
2. light 60 - 70 % 40 - 80 minutes Increase aerobic endurance.
Strengthens body to tolerate higher
intensity training. Increase fat metabolism.
3. moderate 70 -80 % 10 -40 minutes Enhance aerobic power. Improves blood circulation.
4. hard 80 - 90 % 2 - 10 minutes Increase anaerobic tolerance
Improves high speed endurance.
5. maximum 90 - 100 % 0 - 2 minutes Tones the neuromuscular system
Increases maximum sprint race speed.

Some notes:

An important principle is that training improves performance levels during the recovery phase of a training or a race. Sometimes workouts or races are so hard that the day after a workout full recovery has not occurred. In that case, the recovery may be accelerated by training in the gray zone. With a light gear of 42 x 17 and maximally for one or one and a half hour.

Use the entire zone when training in a particular intensity zone. The middle of the zone is a good target, but also the area above and below the target should be addressed.

The heart needs time to adapt to the training intensity. Example, if you want to switch from the gray zone into the green zone, the heart and the blood circulation need time to adapt for 3 to 5 minutes. That means that it needs time changing the intensity zone. So don’t go too fast or too abruptly from one zone to the other zone. Take the time for gradually increasing the speed and the HR.


The response time of the heartbeat on an effort with a certain intensity varies depending on training status, degree of recovery, environmental factors such as cold, heat and other factors as hydration and nutritional status, especially during prolonged efforts. Drinking too little causes a sharp increase in the HR and thus a decrease in the level of performance.

My personal view is that it would be wise not to check the heart rate monitor during training, races or time trials. The rider should try to conduct training instruction by feeling. If with retrospective analysis it appears that the workout order was not well executed the rider has to try to get the right feeling for the intensity of training he is doing during the next workout. In this way a rider learns to feel exactly what feeling corresponds to a particular workout intensity.


See also chapter 006 MAXIMUM HEART RATE (HR max)

The diagram below is suitable for well-trained endurance athletes such as cyclists, marathon runners and triathletes.


WORKOUT Code Percentage HR max Colour zone HR max 200 HR max 190 HR max 185 HR max 180
Recovery R <73 gray 136-146 129-139 126-135 122-131
Easy endurance training EET 73 - 80 green 146-160 139-152 135-148 131-144
Intensive endurance training IET 80 - 87 green 160-174 152-165 148-161 144-157
Tempo endurance training TET 87 - 93 orange 174-186 165-177 161-172 157-168
Deflection point DP 93 red 186 177 172 168
Resistance long RL 93 + 6 red 186-192 177-183 172-178 168-174
Resistance short RS till HR max red 192-200 183-190 178-185 174-180

Compare these results above with the results of the method of Karvonen.

An exercise at intensity below 73 percent of the HR max is regarded as the lower limit. Training under this intensity no longer contributes to an improvement of the aerobic capacity.
To improve the aerobic capacity HR must be between 73 and 93 percent of HR max.
The deflection point or the anaerobic threshold in well trained cyclists is 93 percent of HR max.