Fartlek running is variable speed running, which is to adjust the speed of running according to different terrain and self-perception in order to achieve the purpose of exercising the body. Fartlek running can alternate between slow running, medium speed running, fast running, etc. The duration of this variable speed running is about 30 minutes, which has a great impact on the degree of health of the body, the main thing is that you can lose weight, this variable speed running can reduce muscle memory and can make the body consume more calories, especially subcutaneous fat. Fartlek running can also be adjusted constantly through their own conditions, running speed, for the heart and lung function for a powerful exercise, can improve the function, more suitable for middle-aged people and young people. In addition, Fartlek running can also be beneficial to muscle anti-fatigue, for the relief of mental fatigue and physical fatigue, the effect is very ideal.