1. Improve sports performance: oxygen inhalation can increase the oxygen content and oxygen supply of muscles, thus enhancing sports ability, especially for sports that require explosive force, oxygen inhalation can enhance muscle explosive force and improve sports performance.

2. Accelerated recovery: Oxygen inhalation after exercise can help the aerobic energy stored in the body to be quickly replenished, promote the consumption of lactic acid and the recovery of muscles, and accelerate the recovery process of the body.

3. Improve cardiopulmonary function: Oxygen inhalation can increase the oxygen uptake of the lungs, thus improving cardiopulmonary function. For long-term endurance exercise, oxygen inhalation can improve cardiopulmonary function during exercise and increase exercise endurance.

Side effects of oxygen inhalation by athletes include:

1. Excessive dependence on oxygen inhalation will affect the adaptation and improvement of muscles to oxygen, leading to the dependence of exercise effect on oxygen inhalation.

2. Excessive oxygen inhalation will lead to the imbalance of oxygen and carbon dioxide in the body, which will affect the normal function of the body.

3. If the oxygen inhalation equipment does not meet the standard or is improperly operated, it may lead to oxygen poisoning or other physical problems.

4. Illegal use of oxygen will involve relevant legal issues. Illegal instruction or use of oxygen will also bring some health risks.

Please note that the benefits and side effects of oxygen inhalation vary from person to person and need to be carried out under the guidance of a professional doctor or coach.