One hour is enough, but it's best not to run before eating. In addition, the argument of running a broken muscle is not reliable for the following reasons:

1, protein is not the main energy supply material of aerobic oxidation system.

In the aerobic oxidation system, protein is not the main force, mainly sugar and fat. Because of the abundant reserves, you can keep exercising for a long time.

2. Muscle is not the only source of protein.

Take ten thousand steps back. Even if the aerobic oxidation system needs protein, we will consume protein in our daily diet, which is not the only way to break down muscles, so we can't rudely say that running for a long time will definitely break down muscles.

Extended data:

People's energy is in the process of life activities, all life activities need energy, and energy mainly comes from food. Carbohydrates, fats and protein can release energy through oxidation in the body. These three are collectively referred to as "productivity nutrients" or "heat sources".

Cereals and potatoes are the most economical food sources because they are rich in carbohydrates. Oil crops are rich in fat; Animal foods usually contain more fat and protein than plant foods.

References:

Human Energy-Baidu Encyclopedia