Swimming season begins: what to look for?

In the current heat, rest by the pools and reservoirs gives a person rest. But swimming also has its own rules.
- In what cases is it not recommended to buy?
- What to do when the arms and legs are drawn by vessels in the water?
sign:
At registered water bodies where safety rules are fully observed;
Swimming on a sunny day, in calm weather;
The air temperature must be above 25 degrees
The water temperature should not be below 17-19.
Not recommended:
In wastewater that is not registered, safety rules are not followed;
If you are tired;
If you have overheated in the sun;
When you are hungry;
Thirst.;
after a recent development of the disease;
Also, if your muscles have increased while swimming:
In fact, hands: quickly clench the paw into a fist, strongly clench and release the fist, moving the hand as if it were sharply thrown to the side;
When the muscles of the lower leg tense up: bend over, grab the outstretched palm of the foot, pull it strongly towards you;
When the thigh muscles tense: the face holds the feet outside near the ankle, bend the leg at the knee and pull it back - to the side into the shoulder blades.
Prepared on the basis of Internet resources