Many people living in cities like to do morning exercises in parks or roads in the morning, thinking that after a night of natural precipitation in the morning, the dust in the atmosphere will become fresh and dust-free. Therefore, it is generally believed that morning is the best time for exercise.

Actually, it's not like this. Morning is not the best time to exercise. According to scientific determination, during the period from 7: 00 pm to 7: 00 am, due to weak atmospheric convection, dust pollution near the ground is the most serious. In the morning, especially under the influence of cold high pressure in winter, in basins or valleys, there is often an inverse temperature rise, that is, the upper air temperature is high and the ground temperature is low. Therefore, the convection activity in the atmosphere slows down, and the chemical air pollutants emitted by factories and domestic stoves cannot diffuse into the upper atmosphere, so they deposit and stay in the near-surface layer, which is the so-called human breathing zone. At this time, people who exercise outdoors are just suffering, and the greater the activity, the more serious the pain. Secondly, in the early morning, when people just change from rest to exercise, because the joints and muscles of the body quickly change from relaxation to tension, it is difficult to adapt for a while, and the burden on the cardiovascular system also increases sharply, which is not good for health. Therefore, the suitable exercise time for a day is 10 between the morning and 3 pm, and the best place is in a well-ventilated place with trees and lawns, rather than running and exercising in the factory or on the roadside.