A Los Angeles meteorologist is speaking out after her terrifying on-air fainting that stunned viewers and went viral on social media.

Weather forecaster Alissa Carlson Schwartz collapsed on live TV Saturday morning after her KCAL co-anchors cut to her for the weather report on rain in L.A.

Schwartz hit her head as she fainted and was hospitalized with a head injury. In a Tuesday interview, the meteorologist explained the medical diagnosis behind her health scare.

Doctors diagnosed Schwartz with vasovagal syncope, the most common cause of fainting.

photo of Alissa Carlson Schwartz

L.A. meteorologist Alissa Carlson Schwartz explains the reason behind her fainting episode on live TV. (CBS News / YouTube / Screenshot)

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A vasovagal syncope event happens when your body "overreacts to certain triggers, such as the sight of blood or extreme emotional distress," according to Mayo Clinic.

Dehydration and skipping meals are also two risk factors for developing the condition, Cedars-Sinai Hospital says.

The triggers can cause a person's heart rate and blood pressure to drop suddenly, which reduces blood flow to the brain and causes the person to faint.

Dizziness, clammy hands, blurred vision and nausea are common symptoms before passing out.

woman with headache, migraine, stress, insomnia, hangover

Blurred vision and dizziness can occur before a vasovagal syncope event. (Kharichkina)

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Schwartz explained that she felt fine up until about 15 minutes before she went on the air. The weather forecaster said she started to feel a little nauseous but decided to "power through" the upcoming segment.

She had also skipped breakfast that morning and was a little dehydrated from drinking coffee.

Schwartz revealed she had previous fainting episodes before this. She was also diagnosed with a leaky heart valve nearly a decade ago, but she said this episode was unrelated as doctors told her she passed all her cardiac tests.

The meteorologist revealed that she wished she had listened to her body's warning signs and laid down when she started to feel sick. She said the episode was a wake-up call to take better care of herself.

Woman sleeping

The meteorologist urged others to get enough rest and stay hydrated. (iStock)

She emphasized the importance of getting enough sleep and staying hydrated.

"Sometimes we put ourselves last, we go go go until something happens, and then it's too late," Schwartz said.

Fox News' Yael Halon contributed to this report.