Gov. Mark Dayton was taken to Regions Hospital in St. Paul on Sunday after he fainted at a political event, and was hospitalized overnight for observation, officials in the governor's office said.

"He is in great spirits," said senior adviser Bob Hume, who spent two to three hours with Dayton at the hospital. "The most likely culprit is dehydration."

The governor is undergoing tests as a result of the incident, which occurred in Woodbury about 5 p.m. during a volunteer recognition event for state Rep. JoAnn Ward, DFL-Woodbury, Hume said.

Jaime Tincher, the governor's chief of staff, said in a news release that the event was hot and crowded, and Dayton fainted after feeling increasing pressure in his lower back.

Hume said the governor's office plans to issue a release when the governor leaves the hospital.

Anthony Lonetree