Most people worry about dogs not getting enough water in summer. Fewer know the opposite can go wrong too. A dog who spends an hour diving for a toy, mouth wide open, can swallow far more water than anyone realizes.

It's not common, but when it happens it's serious, and the warning signs are easy to mistake for "he just got tired." Here's what to know before the next game of fetch in the pool.

What's Actually Happening

When a dog takes in a large amount of water quickly, it can dilute the salts, especially sodium, in the bloodstream. Vets call the result water intoxication, or hyponatremia. The body's cells take on water they shouldn't, and the effects can reach the brain.

It usually isn't from a dog calmly drinking from a bowl. It's from repeated retrieving, biting at the water, or scooping with an open mouth, the kind of play that moves a lot of water through a dog in a short time.

The Warning Signs

• 🐾Vomiting or retching, sometimes with clear fluid
• 🐾Sudden lethargy or a dog who just wants to lie down
• 🐾A swollen or bloated belly
• 🐾Loss of coordination, stumbling, or a glazed look
• 🐾Excess drooling, pale gums, or trouble standing

Dogs Most Likely to Take On Too Much

The risk tends to follow the play style, not the breed. Obsessive retrievers, dogs who bite at hose streams or sprinklers, and dogs who dive for toys on the bottom of the pool are the usual candidates. Smaller dogs have less room before it adds up.

Easy Ways to Lower the Risk

• 🐾Pick toys that float and are easy to grab without a deep, open-mouth dive.
• 🐾Break up the retrieving. Short rounds with real rests in between beat one long session.
• 🐾Toss on land near the water instead of constantly into it.
• 🐾Give your dog a place to rest out of the splash zone, so the game actually pauses.

That last one matters more than it sounds. A dog with a comfortable spot to climb onto will often take the breather on their own, and a dog who isn't mouthing the water for a few minutes at a time is a safer dog.