Formula 1 race winner Rubens Barrichello recovering in hospital

The Brazilian, who won races for Ferrari and Brawn in a career that spanned 322 grand prix starts, said he felt unwell on Saturday after suffering a severe headache.

Speaking from his hospital bed in a message posted on his Instagram feed, Barrichello explained that he was still undergoing checks but vowed to be back racing soon.

He did not offer any details of what was wrong, beyond suggesting it was related to a vein problem.

"I can see everyone is sending me messages and everyone is worried," he said.

"A long time not posting pictures and so on, so I decided to tell you.

"On Saturday I decided to wake up and have a shower. I felt a terrible headache.

"Luckily my wife was there and she called a friend doctor who took me to the hospital, they took really good care of me.

"I had a small problem on a vein, but I want to tell you that I am feeling great.

"I am still going through exams and so on, but I am honestly great and the difficulties in life are the ones who show us how to grow and how to be better.

"I am so thankful, thank god for the opportunity and soon I will be back on the racetrack. So good to speak to you guys."

Since retiring from F1 at the end of 2011, Barrichello has raced primarily in Brazilian Stock Cars - where he won the '14 title - as well as spending a season in IndyCar and contesting the '17 Le Mans 24 Hours.

Recently he has also focused on helping his son Eduardo's karting career.