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A test developed in the USA by cardiologists and exercise physiologists to determine fitness and monitor progress during an exercise programme. The fitness ratings are based on the speed at a walk exactly 1.6 km (1 mile) is completed on a flat course, and the effect of the walk on heart rate (assessed from a 15-s count of pulse rate immediately after the walk is completed). The faster the walk is completed and the lower the effect of walking on heart rate, the fitter the person is.