President Shimon Peres was discharged from hospital on Sunday with a clean bill of health, a day after the 86-year-old Nobel peace laureate passed out briefly at a ceremony.

"I can say to everyone that we have a president who is dynamic, young at heart and physically healthy," said Dr. Zeev Rothstein, director of Sheba Medical Center at Tel Hashomer near Tel Aviv, where Peres was kept for observation overnight.

Peres' spokeswoman Ayelet Frisch blamed his notoriously grueling schedule for the collapse.

Frisch said tests conducted at the hospital indicated no problems. She added that Peres would meet later Sunday with U.S. Mideast envoy George Mitchell.

Dr. Rothstein said there was no immediate explanation for the weakness that overcame Peres as he spoke in Tel Aviv on Saturday night and lost consciousness for several moments, and that tests had so far shown him to be in "excellent condition."

Peres is not known to suffer from any health problems.

Prime Minister Benjamin Netanyahu on Sunday said that he spoke with Peres.

"I told him that aside from meeting Mitchell, he should rest a bit because I believe that every Israeli is genuinely concerned for our President," said Netanyahu.

He added, "I am certain that I speak for every member of the government when I say that we wish him good health and continued productive activity on behalf of the State of Israel."

Peres on Saturday night said he 'feels fine' after he collapsed during a question-and-answer session for young executives at the Rabin Center in Tel Aviv hours earlier.

The president collapsed on the lectern during the last question. He recovered consciousness after a few seconds, at which point he was taken to a side room where Magen David Adom medics treated him.

The president's personal physician later rushed to the scene.

After the incident, people close to Peres told Haaretz that he was feeling "good," that he left the hall walking, and that he had a protracted debate with his aides about whether to go to hospital - which the president refused to do.

Peres was ultimately taken to the Sheba Medical Center at Tel Hashomer for further treatment.

At the hospital, Peres told the many aides who flocked to visit him that, "I feel fine, why did you come to the hospital? Go back to your children."

Peres later spoke to Prime Minister Benjamin Netanyahu and also told him that he feels fine.

"The president apparently suffered a drop in blood pressure," Peres' spokeswoman Ayelet Frisch said. "He is now fully functional and his personal doctor ran a series of tests which were normal," she told Israeli television. "We can relax now. I've spoken to him and he's fully conscious."

Peres, Israel's ninth president, conducts a busy schedule, despite his age. Over the last few days he has held a series of policy meetings with the Spanish foreign minister, Miguel Angel Moratinos; he also flew to Russia last month for meetings with President Dmitry Medvedev.