Daily moderate activity reduces markedly several population diseases. Still many persons do not perform any regular physical activity. Many persons quit because they exercise at too low intensity that does not give result, or at too high intensity that is not comfortable. By exercising at an established adequate workload, optimal for the individual, the person can see results of the training and the quitting behavior can be changed. In sport at top level, the lactate threshold is used as a guideline for adequate workload, and to see changes in fitness. The lactate threshold is generally established by blood tests.