HONOLULU -- U.S. Sen. Dan Akaka said he's "disappointed" that fellow Democrat U.S. Rep. Ed Case is challenging him for his Senate seat. However, Akaka said he's looking forward to the campaign.

Akaka spoke to KITV from Washington. He said he wasn't surprised when Case called him with the news on Thursday because Akaka said he's heard rumors about it for months.

"Of course I am disappointed. The delegation is disappointed, but he has every right to do what he is doing," Akaka said.

---

Interactive: Survey | Discussion | Case Decision | Reaction

---

Akaka said he is healthy and ready for a re-election challenge from Case, who is 28 years younger than him. Akaka is 81 and Case is 53.

"It energized me because that announcement brought a lot of calls from many friends and people across the state of Hawaii, offering their love, their best wishes, their support," Akaka said.

Case said Hawaii can't afford to have two senior senators in their 80s possibly depart around the same time, potentially losing a lot of seniority in the Senate.

Akaka is the 34th most senior member in the 100-person Senate.

"We have been able to get things done in the U.S. Senate with all those years of experience. And, a person that's coming in new will start from the bottom," Akaka said.

In the last five years, Akaka has had both knees and a hip replaced. However, he said he's physically up for the job of representing Hawaii in the Senate for another six years.

"I have a clean bill of health. I exercise every day," Akaka said.

Akaka would not commit to debating Case face to face.

"Should that come about, I may consider it and I may not, but we'll see," Akaka said. "I think people know what has been done, how I feel and how I think, and I think that's all that's necessary."

Akaka said he expects to spend at least $1 million in the race. His campaign spent about $2 million 15 years ago, when he was first elected to the Senate, beating Republican Pat Saiki.

Akaka said he's planning to return to Hawaii to do some campaigning during a Senate break in February and may do so sooner if his schedule permits.