Ron Paul, the former Republican representative who ran for president three times, was hospitalized on Friday in Texas for "precautionary" reasons, Fox News has learned.

Paul, 85, was speaking about the free market during a livestream on his YouTube channel when his speech began to slur earlier in the day. He is "lucid" and "optimistic," Fox News learned.

"I am doing fine," Paul said in a later statement posted to his Twitter, along with an image of him in a hospital bed. "Thank you for your concern."

His son, Kentucky Sen. Rand Paul, did not immediately respond to a Fox News' request for comment. But he tweeted his father was doing "well."

"Thank God, Dad is doing well," he tweeted. "Thank you all for your prayers."