Throwing water over a heat stroke victim has no adverse effects at all. It is throwing water on a heat stroke victim that is dangerous.
Find a cold spot and give them lots of cold water and maybe an ice pack.
wrap the victim in a blanket and provide warm drinks
Drowning. The immersion in cold water often causes the victim to suddenly exhale the air that is in their lungs instead of holding it in as long as possible.
In cases of cold water immersion, it's crucial to seek medical help immediately, as hypothermia can be life-threatening. While waiting for assistance, warm the victim gradually using dry blankets and warm, non-alcoholic drinks like hot coffee, if they are conscious and alert. Avoid making the victim run laps or using hot water abruptly, as these can cause shock or further complications.
I wouldn't call it dangerous, your body needs both the water and the food. To the worst, you might upset your stomach for awhile.
wrap the victim in a blanket and provide warm drinks
Cold slows the rate of metabolic reactions in the body (e.g. pulse, digestion, etc.). When jumping into cold water, the heart rate can slow to a dangerous level while having to pump harder to keep the body warm. The body knows what is dangerous and sends signals to the brain when something could jeopardize safety. Jumping into cold water would cause the same amount of fear as boiling water.
wrap the victim in a blanket and provide warm drinks
To treat a victim of cold water immersion, first, remove them from the cold environment and gently warm them, preferably using dry blankets or warm, dry clothing. Avoid rapid rewarming methods, such as hot baths, as they can cause shock. Monitor their breathing and circulation, and seek medical attention immediately, as hypothermia can have serious complications. If the victim is conscious, provide warm, non-alcoholic, non-caffeinated beverages to help raise their core temperature.
In cold packs is usedAmmonium nitrate. It's dangerous because it can explode. But for this it must be absolutely dry.In a cold pack it is in a water solution. Nevertheless you shouldn't eat it or contact it a long time with your skin. In case of a damage of the cold pack you can just wash it away with water.
If the hypothermia is mild, it can be treated by warm blankets and warm fluids in as warm an environment as possible. Drying off the victim (if wet) will help as well, as water is extremely efficient at conducting heat away from the body. In severe cases, immediate hospitalization is required. Ironically, if the victim appears to be dead, maintaining the hypothermic condition can increase their eventual chance of recovery, by reducing the amount of critical cell damage associated with heart failure and stopped breathing.
Stabilize the victim and remove from the cold as quickly as possible.