1. People suffering from severe heart disease, hypertension and mental disorders are prone to sudden fainting or unconsciousness when entering the water.

2. People who are prone to convulsions due to epilepsy should not swim in case of sudden onset and loss of swimming skills.

3. Patients with infectious skin diseases such as viral hepatitis, bacillary dysentery, pinkeye, sexually transmitted diseases and tinea corporis should not take part in swimming to prevent the spread of infectious diseases.

4. Deaf-mute people should not take part in swimming, because the organs that regulate the balance in the middle ear of deaf-mute people will also be damaged, thus weakening the balance ability of the body, and often drowning accidents occur because of losing balance.

5. After the perforation of the tympanic membrane into the water, the water will enter the middle ear cavity through the perforation of the tympanic membrane and cause acute otitis media, so it is not suitable for swimming. People with suppurative otitis media can't swim, because pus with bacteria in the middle ear cavity may flow into the swimming pool water, polluting other swimmers and making them have an acute attack of chronic suppurative otitis media.

6. Women can't swim during menstruation, pregnant women, within two months after delivery, within one month after induced abortion or tubal ligation, and within half a month after Sheung Wan.

7. People with tuberculosis, emphysema, nephritis, trachoma, acute conjunctivitis, corneal ulcer, high myopia and acute sinusitis should not swim; People and alcoholics should not swim immediately after strenuous activities.