This past weekend, I was relaxing by a lake watching a family play fetch with their dog.

At first it was such a delightful sight to see. The kids threw a big stick in the water and waited for their pup to retrieve it. They all looked like they were having so much fun.

After half an hour of playtime, the doggo started to get tired. You could tell that he still wanted to play, but that he didn't have the energy to keep going.

I didn't think too much of it until the dog started acting more strange. He dragged his body out the water, vomited, and swayed as if he was drunk.

The family started to pick up on their beloved pet's behavior and looked very worried.

Before I could offer to help, they packed up their belongings and left.

That's when I remembered a story for last year about a dog dying after playing fetch in a lake.

Apparently, this common game is very dangerous! I think it's about time for the story to be told again before more dogs lose their lives.

The Hidden Danger Behind A Common Game

A California family was enjoying a day by the lake playing with their two-year-old schnauzer, Hanz, when their world suddenly turned upside down.

They were doing what any fun, loving owner would do on a beautiful day by a large body of water: They played fetch with their dog.

They threw sticks and balls for Hanz, watching their beloved family pet have a good time.

"He was very active, very excited, chasing the stick, and we were all having fun," Jen Walsh told Inside Edition.

An hour and a half later, Hanz began shivering in the water.

Strange Symptoms

The family got him got, but he just stood there. "Dogs always shake themselves off when they're wet," she said, but Hanz didn't,

Instead, Hanz started peeing everywhere.

His family described him looking "lethargic" and "cold." His tongue was hanging to the side and his breathing was uneven.

"We needed to take him to the vet," Walsh said. "At that point, he wasn't even walking. We carried him."

On their way to see the vet, Hanz stopped breathing, which was 45 minutes after he showed his first symptoms of hyponatremia.

Water Intoxication

The vet explained that Hanz suffered from water intoxication or hyponatremia, which is a condition that lowers the sodium levels in the blood, causing fatal brain damage.

"You hear about dogs that do swimming competitions and you never hear about that being a concern for them," Walsh said. "It can apparently happen to any dog."

Wash recalled that Hanz played in the pond in their backyard many times, but he never showed unusual symptoms.

"It was awful," Walsh said. "[My daughter] is very traumatized by all this ... If we had known about water intoxication, maybe there would have been something more we could have done to save him."

How To Protect Your Dog

Some dogs love playing in the water. This story isn't meant to scare you from ever playing fetch with your dog ever again, but to be aware of the potential dangers.

According to experts, water intoxication usually occurs in smaller dogs that have less body fat.

If you notice your dog becoming lethargic, having difficulty breathing, or vomiting after playing in water, take them to see the veterinarian immediately.

Keep in mind, it's not only dogs that can suffer from this fatal illness. Water intoxication can also occur in young children.

[H/T: Newsner / Inside Edition]

For more tips on how to help your dog live a longer and healthier life, click here.