Actress Brooke Shields shared in a recent interview that she had a "grand mal seizure," which she attributed to drinking too much water.

While preparing for her one-woman show, "Previously Owned by Brooke Shields," the actress, 58, said she consumed so much water that her sodium levels dipped to a dangerously low level.

At the hospital, doctors confirmed that Shields "had too much water," she said in her Glamour 2023 Women of the Year interview. 

"I flooded my system, and I drowned myself. And if you don’t have enough sodium in your blood or urine or your body, you can have a seizure."

In describing the event, Shields said she was "frothing at the mouth, totally blue, trying to swallow my tongue. The next thing I remember, I’m being loaded into an ambulance. I have oxygen on."

What is a grand mal (tonic-clonic) seizure?

During a grand mal seizure — which is now officially called a tonic-clonic seizure — the muscles alternate between the tonic phase (stiffening) and the clonic phase (jerking or twitching), according to the Johns Hopkins Medicine website.

Early warning signs often include a "simple or complex partial seizure," also known as an aura, along with changes in mood or emotion and abnormal sensory experiences.

Once the tonic activity begins, the person may lose consciousness, cry out, fall down and/or drool or foam at the mouth, according to Johns Hopkins.

If the seizure causes impaired breathing, the person may appear to be gasping for breath or may take on a gray or bluish skin tone.

In the clonic phase, the person’s body will begin to jerk, usually for one to three minutes. 

After that, the body will relax and the jerking movements will stop.

After a person suffers a seizure, it usually takes a few minutes for the brain to recover. 

During that time, the person may appear to be sleeping or unconscious.

Tonic-clonic seizures require immediate medical treatment, according to Johns Hopkins — as the muscle spasms can interfere with breathing.

Treatments may include medication, surgery, dietary therapy and/or nerve stimulation.

How much water is too much?

Dr. Pooja Patel, director of the epilepsy monitoring unit with Marcus Neuroscience Institute, part of Baptist Health South Florida, at Boca Raton Regional Hospital, confirmed to Fox News Digital that drinking too much water can be dangerous.

"It can cause hyponatremia (low sodium)," she said in an email. "Extreme hyponatremia can cause severe adverse effects on the body."

One of those potential effects is seizures.

"With severe hyponatremia, water moves to the brain, causing brain cells to swell up," Patel said. "If this is acute, it can cause increased pressure and seizures."

The recommended amount of water is approximately eight glasses per day, with one glass equaling 8 ounces, according to the doctor.

"Usually, staying close to this is safe," she said. 

"If you drink excess amounts of water, especially if you have a preexisting condition, it can cause detrimental effects like hyponatremia."

While staying hydrated is very important, Patel recommends checking with a health care professional to determine a safe water intake before making sudden changes to your diet — especially for those who have any preexisting medical conditions.