Iowa Republican Gov. Terry Branstad was rushed to the hospital in an ambulance on Monday after falling ill at an event at a Des Moines suburb, the governor's office said.

Branstad has been fighting a cold, and initial tests indicate he reacted to a "seasonal illness," said Branstad's spokesman Jimmy Centers, who noted that the 68-year-old was conscious, alert and responding to questions, according to the Des Moines Register.

"The governor had been suffering from the effects of a cold for a couple of days," Centers said, adding in a later release, "During the transport, paramedics took the governor's vitals and initial tests indicate that the spell was caused by a seasonal illness."

On Monday, the six-time governor required assistance at a ribbon-cutting event for a new research center at DuPont Pioneer in Johnston. Previously in the day, he had told reporters that he was suffering from a bad cold after coughing throughout his weekly news conference.

But during his speech at the DuPont event, he began to struggle with his words and appeared to grow unsteady, Reuters reported.

Immediately, he was laid on the ground and then later sent to Iowa Methodist Medical Center in Des Moines.

Branstad served four terms as Iowa's governor from 1983 to 1999 and then returned to win an election in 2010 and reelection in November.

In December 2000, Branstad had a heart attack and doctors inserted a stent in his heart to keep an artery open. In May 2010, Branstad's doctor located a partially blocked artery in his heart during a routine angiogram. Branstad had a second stent inserted in his heart, the Associated Press reported.

The 68-year-old, who is on track to become the longest-serving governor in U.S. history later this year, also had outpatient surgery to treat varicose veins in his legs last month.

A spokeswoman for DuPont Pioneer did not immediately return a call seeking comment.