Gov. Mark Dayton was released from Regions Hospital in St. Paul on Monday after fainting at a political event in Woodbury the night before.

The governor was treated for dehydration, said Bob Hume, the senior adviser to the governor.

Dayton fainted during a volunteer recognition event for state Rep. JoAnn Ward, DFL-Woodbury.

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.

The governor, 69, had a spinal fusion at Mayo Clinic in December, his second back procedure in recent years.