A, avoid swimming before and after meals Fasting swimming will affect the appetite and digestive function, but also in swimming dizziness and weakness and other unexpected situations; full stomach swimming will also affect the digestive function, but also produce stomach cramps, and even vomiting, abdominal pain phenomenon. Second, avoid swimming after strenuous exercise Strenuous exercise immediately after swimming, will make the heart added burden; body temperature of the sharp drop, will weaken the resistance, causing colds, laryngitis, etc.. Third, do not swim during menstruation Swimming during menstruation, germs are prone to enter the uterus, fallopian tubes and other places, causing infection, resulting in menstrual disorders, excessive menstrual flow, prolonged periods. Four, avoid swimming in unfamiliar waters When swimming in natural waters, do not rush into the water. Where the water around and underwater conditions are complicated are not suitable for swimming to avoid accidents. Five, do not swim for a long time exposure to the sun Prolonged exposure to the sun will produce sun spots, or cause acute dermatitis, also known as sunburn. To prevent the occurrence of sun spots, it is best to use an umbrella to shade after going ashore, or to rest in the shade, or use a towel to protect the skin on the body, or in the exposed parts of the body coated with sunscreen. Avoid swimming without preparation activities The water temperature is usually lower than the body temperature, so you must do preparatory activities before going into the water, otherwise it is easy to lead to discomfort. Seven, avoid eating immediately after swimming After swimming, it is appropriate to rest for a moment before eating, otherwise it will suddenly increase the burden on the gastrointestinal tract, which can easily cause gastrointestinal diseases. Eight, avoid swimming for too long Skin to cold stimulation generally has three reaction period. The first period: after entering the water, stimulated by the cold, skin vasoconstriction, skin color is pale. The second period: after staying in the water for a certain period of time, the body surface blood flow expansion, the skin from pale to light red, the skin body from cold to warm. The third period: stay too long, body temperature heat dissipation than heat, skin goose bumps and shivering phenomenon. This is the contraindication period of summer swimming, should be promptly out of the water. The duration of swimming should not exceed 1.5 to 2 hours in general. Nine, avoid swimming with a history of epilepsy Whether major or minor seizure type, there is a momentary loss of consciousness during the seizure, if suddenly induced in swimming, it is inevitable that "the end of the disaster". Ten, avoid hypertensive patients swimming Especially stubborn hypertension, drugs are difficult to control, swimming has the potential risk of inducing a stroke, should be absolutely avoided. Eleven, avoid heart disease swimmer Such as congenital heart disease, severe coronary heart disease, rheumatic valve disease, more serious arrhythmias and other patients, swimming should be "respectful and far away". Twelve, avoid swimming with otitis media Whether it is chronic or acute otitis media, water entering the inflamed middle ear is tantamount to "adding insult to injury" and aggravating the condition, and can even cause intracranial infection. Thirteen, do not suffer from acute conjunctivitis swimming The virus of the disease, especially in the swimming pool, the speed of infection, the range of surprising. In the epidemic season of the disease even healthy people, should also avoid swimming in the pool.