target heart rate; training zone
A heart rate reached in training that indicates the level of exercise which produces maximum training effects (figure 64). The method most commonly used to estimate training heart rate for aerobic exercises on land is to take 60-80 per cent of maximum heart rate (assumed to be 220 minus age). Heart rates in water are naturally lower than on land. This is partly due to the support that the water gives the body. Therefore, for swimming the maximum heart rate is assumed to be 205 minus age, rather than 220. The training heart rate should be determined in relation to the type of activity and fitness level of the individual. Anaerobic training requires higher heart rates (up to 95 per cent maximum heart rate) sustained for short periods. Unfit people should train at the lower end of the range. For example, a relatively unfit person of 35 years would have a training heart rate (THR) of 60 per cent maximum heart rate, i.e.:
THR = (220-35) × 0.60= 111 beats per minute.Training heart rates are only estimates. Exercisers should always be aware of symptoms, such as breathlessness, dizziness, and pains in the chest, which indicate that the training level is too high. Those with health problems should seek medical advice concerning their level of activity.
Figure 64
