KCAL-TV meteorologist Alissa Carlson made national headlines over the weekend when she fainted rather dramatically on-air Saturday morning immediately after having been introduced by the broadcast's anchors.

Thankfully, Carlson is fine, and appeared on "Good Morning America" Tuesday to explain what happened.

"It wasn't really until 15 minutes prior to the incident that I started to feel a little nausea," Carlson said. She wrote the discomfort off as likely due to dehydration and decided to push through her morning.

The result of that decision was her collapse on live television:

Carlson told the GMA anchors that doctors had diagnosed her with vasovagal syncope.

She was relieved at the news, she said, because she knew she had a leaky heart valve and was concerned that she had had a heart attack.

"Heart tests prove I'm fine, my heart is great," Carlson said.

CBS News chief medical correspondent Dr. Jon LaPook broke that down for viewers: "vagal" refers to the vagus nerve, "vaso" is a reference to blood vessels, and "syncope" simply means a temporary loss of consciousness, usually caused by low blood pressure, according to the American Heart Association.

"If the vagus nerve is overstimulated or inappropriately stimulated, the pulse rate can go down, the blood pressure goes down, not enough blood goes up to the head and you can faint," LaPook said.

According to the Cleveland Clinic, the vagus nerves control "specific body functions such as your digestion, heart rate and immune system."

LaPook said that warning signs that you might be about to experience vasovagal syncope include dizziness, graying out or tunnel vision, and sweaty palms.

The problem with those symptoms, he said, is that they tend to cause people to sit up straight while waiting for them to pass.

""People, like especially in this situation, you're embarrassed," he said. "'I'm going to sit up and look normal.'

"[But t]hat's the worst thing you can do. You want to get flat so your heart is at the same level as your head."

Lying flat on your back with your legs up is the best response, he said, to get your blood pressure to where it needs to be to prevent a blackout. He also suggested keeping your head turned to the side, in case of vomiting.

Of course, if you're a television meteorologist about to go live on the air, "that's the last thing you'd want to do," LaPook acknowledged.

"Sometimes we put ourselves last, we go-go-go, until something happens," Carlson said. "And then it's too late."

This article appeared originally on The Western Journal.