Is foggy weather not suitable for running?

Definitely inappropriate. The air pollution is heavy in foggy days, and there are many harmful substances in the fog. Outdoor running does more harm to your health than exercise.

When running in foggy morning, due to fog and water vapor, it will hinder the exchange of oxygen and carbon dioxide between alveoli, making body organs and tissues hypoxic. Therefore, when running in the fog, it is easier to feel poor breathing, chest tightness and discomfort, dizziness due to lack of oxygen in the brain, and fatigue.

Fitness and running are generally best arranged in the morning, followed by around 9 am and 5 pm. Middle-aged people usually exercise in the morning because of work. First of all, they don't conflict with work. Second, running in the morning has fresh air, which is good for the respiratory system. In addition, after sleep, people's physical strength is restored, but physiologically, people still have a certain degree of inhibition. Morning exercise is beneficial to nerve excitement, mental stimulation, metabolism promotion, and it is of great benefit to maintain abundant spirit and physical strength in a day's work.

References:

Baidu Encyclopedia _ Running