Sen. Johnny Isakson, R-Ga., disclosed Wednesday he has Parkinson's disease, but said the diagnosis won't deter him from seeking a new term next year or compromise his ability to serve if he wins.

In a written statement, Isakson said he takes two medicines for his condition, first diagnosed in August of 2013. Parkinson's is a chronic and progressive movement disorder, and the 70-year-old lawmaker in recent months has walked with a noticeably slower, shuffling gate that he said is a symptom of his disease.

Isakson, in his second Senate term, is heavily favored to win a third next year in his strongly Republican state. Democrats have yet to field a challenger. He won 58 percent of the vote in his most recent campaign, in 2010.

Even so, Isakson's announcement emphasized an ability to keep up with a heavy workload, and included a statement from his neurologist.

"I believe he is fully capable of continuing to perform his duties as a U.S. senator, and I believe he is capable of running for re-election and serving for another term," wrote Dr. Thomas M. Holmes.

Holmes said he has concluded that Isakson is "in stage 1.5 of 5 accepted stages of Parkinson's disease....indicative of his mild symptoms."

Gov. Nathan Deal also expressed confidence that Isakson will “meet this challenge.”

“In the 35 years that I’ve known Johnny Isakson, he has risen to meet — and overcome — every obstacle he’s encountered with determination and a smile on his face,” Deal said in a prepared statement. "There’s not a doubt in my mind that he and Diane will rise to meet this challenge. As he fights this battle, our distinguished senator will continue representing Georgians’ conservative principles in Washington."

Isakson said recovery from a back operation in 2014 has also affected his gait. He said he does exercises twice a day.

In his statement, Isakson said his diagnosis hasn't impacted his ability to serve in the Senate. "I am busier and have more responsibility today than ever before in my political career," he said.

Isakson chairs the Committee on Veterans Affairs, as well as the ethics panel.