Simone Biles details unexpected reason she carries 'emergency' anxiety medication in her bag

US Olympic gymnast Simone Biles has shared the details of her 'emergency' anxiety bag that she travels with 'just in case'.

The 29-year-old was taking part in the 'What's in my bag' trend as she opened up about her fear of flying.

In a clip on her Instagram, the star admitted: "I also have my emergency anxiety meds, which, there's a story behind that... they're just in case I get nervous on flights or before flights."

Also in the athlete's bag was her passport, 'content phone', chargers, perfume, and more.

While Biles didn't go into the details of the anxiety medication she travels with, they are often prescription drugs used to calm the mind and reduce physical or mental symptoms of panic and stress, according to Medical News Today.

And she is far from alone in her fear of boarding a flight. A long-running CBS News/YouGov poll found that just 41 percent of Americans said they were 'not at all afraid' of flying.

Common types of anti-anxiety medication that can be prescribed include daily antidepressants like SSRIs, fast-acting sedatives, and alternative options such as buspirone or beta-blockers.

According to the outlet, the prescription drugs works to help combat excessive fear, persistent worry, and the physical symptoms of stress that are caused by the body's overactive 'fight-or-flight' response. They aim to restore balance to brain chemicals like serotonin, norepinephrine, and GABA, to make daily stressors manageable.

And the update comes just weeks after she had been rushed to the hospital following a life-threatening medical emergency.

"'I'm not one to normally share things like this because I value privacy in today's age," Biles shared with her loyal fans, "But almost dying wasn't on my bingo card earlier this week."

Recalling the traumatic experience, she said: "This was one of, if not the scariest experience of my life, especially since Jonathan was in Indy for practices.

"I've been in bed resting this week, I'll explain sooner or later but s/o to my close circle who reached out, checked in, visited & or sent flowers."

Just last week, she shared an Instagram selfie from a hospital bed alongside her husband, NFL safety Jonathan Owens.

The gymnast joked that Owens was spending his 31st birthday by her bedside, but did not disclose what procedure she had undergone.

But it's not the first time Biles has suffered a health scare, as she previously opened up about the toll the Paris Olympics had on her body.

"I went back to the village, took the elevator, and my body literally collapsed," she told L'Equipe. "I was sick for 10 days.

"The other day, we were sprinting in the garden with friends,” she added. "I had aches and pains for three days."

Biles suffers from a condition known as 'Twisties', which means she can experience a loss of spatial awareness mid-air.