1. Exercise effect: run for half an hour at 6 kilometers, that is, pace for 3 minutes per kilometer. This speed belongs to a relatively fast level, and the muscles of the whole body will participate in the exercise. The body will release a lot of glycogen and fat to provide energy, and the heart rate will be accelerated, which is more obvious for the exercise of cardiopulmonary function. The speed of 6 kilometers and 40 minutes is normal, the body will burn fat to provide energy, and the exercise of cardiopulmonary function is relatively weak.

2. Fitness effect: Running for six and a half kilometers can consume a lot of calories and burn a lot of fat. For people who often run, this is equivalent to a comprehensive fitness training. Although 6 kilometers and 40 minutes can also burn calories and fat, the fitness effect is relatively weak because of the relatively slow speed.

Generally speaking, the main difference between running for half an hour and 40 minutes in 6 kilometers lies in the exercise effect and fitness effect. The former has more obvious exercise on cardiopulmonary function, while the latter pays more attention to overall fitness.