Note: I am not a doctor and this should not be considered medical advice.
You need to avoid dehydration since the problem increases the likelihood of diving injuries. To avoid dehydration, you must do the following:
Protect body temperature and remain as warm as possible. You Produce more urine when your cold.
Maintain your regulator, so you can breathe as conveniently as feasible. The dry air from the tank and breathing resistance will cause increase dehydration.
Be aware of diuretic drinks, supplements, and medications.
Replenish your body liquids often; drink liquids prior to and between dives.
Note: If you are thirsty, you are already dehydrated. Be aggressive about hydration and drink a minimum of 500ml of water of after every dive. An excellent after-dive drink is a sports drink diluted with an equal amount of water. Avoid alcoholic beverages since it increases dehydration.