U.S. Senator Chuck Grassley announced at 4 o’clock this morning that he is running for re-election.

Grassley’s campaign account on Twitter features a GIF of the Senator running, plus a photo of Grassley in a corn field, with a sentence quoting Grassley as saying he “has a lot more to do, for Iowa.” During an interview with Radio Iowa earlier this month, Grassley said he was gauging the opinions of Iowans on the topic.

“I don’t have just a few people say, ‘You ought to retire, ‘ and maybe those are people who want me to retire because they want to elect a Democrat,” Grassley said. “I don’t know their motives, but I get a lot of people who encourage me to run and say: ‘We need your common sense there.’ That’s very encouraging.”

Grassley celebrated his 88th birthday on Friday. He is one of seven senators who are in their 80s and Grassley said his age is no reason to retire from the Senate.

“Don’t you think octogenarians need some representation, too?” Grassley said, with a laugh. “That’s kind of a tongue in cheek answer, but don’t you think you need a little institutional knowledge around?”

Grassley said he’s had his annual physical, is healthy and goes for a run before sunrise six days a week. Grassley could face a GOP Primary challenger next year, as Republican State Senator Jim Carlin of Sioux City announced earlier this year he’s running for the U.S. Senate. Three Democrats have announced they’re seeking a spot on the 2022 ballot to challenge Grassley. Abby Finkenauer of Cedar Rapids is a former member of the U.S. House. Dave Muhlbauer of Manilla is a former Crawford County Supervisor. Glenn Hurst, a member of the Minden City Council, is a physician.