Updated

Israeli President Shimon Peres was discharged from a Tel Aviv hospital on Sunday, a day after fainting on stage during a talk.

The 86-year-old Nobel laureate passed out briefly Saturday, then revived on his own a few seconds later. He initially resisted hospitalization, but later relented and was admitted to a hospital for observation and tests.

Spokeswoman Ayelet Frisch blamed Peres' notoriously demanding schedule and the intense summer heat for the collapse. Peres was answering questions from a crowd after a talk on young leadership on a humid night when he collapsed, she said.

The director of the Sheba Medical Center, Dr. Zeev Rotstein, told Israeli media on Sunday that tests showed Peres to be in good health.

Peres' personal physician, Dr. Rafi Valden, told Israeli media the president was doing well. Valden, who is also Peres' son-in-law, said Peres felt weak from standing for a long time in the heat.

The Israeli president is not known to suffer from any health problems, aside from high blood pressure that is treated with medication. Peres' medical history is open to the public and he travels with a paramedic.

Despite his advanced age, Peres keeps a very busy schedule and is known to go full speed on little sleep.

Frisch said Peres was resting Sunday but planned to keep a meeting later in the day with U.S. Mideast envoy George Mitchell, who is in the region trying to renew stalled peace talks between Israel and the Palestinians.

Israeli Prime Minister Benjamin Netanyahu said he had spoken to Peres, who assured him he was well.

"He sounded as excellent as always. Of course, it is impossible to stop Shimon," Netanyahu said at the start of the weekly Cabinet meeting. "He spoke with me about what he plans to tell envoy Mitchell. 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."

French President Nicolas Sarkozy also dispatched a letter to Peres saying how pleased he was to learn that Peres had recovered from the brief medical scare. Egyptian President Hosni Mubarak also called to wish him well.

Peres has enjoyed a political career spanning seven decades.

He was a senior aide to the country's first prime minister, David Ben Gurion, developed Israel's nuclear program, built up the military in the 1950s and has held every senior government post, including two stints as prime minister.

In 1994, he was awarded the Nobel Peace Prize for his efforts to bring peace with the Palestinians.

In 2007, he was elected to the country's ceremonial presidency. In addition to his official duties, Peres has also immersed himself in peacemaking efforts as president, working long hours and traveling the world frequently as an unofficial adviser and envoy for Israel's prime minister.

Despite pleas from friends and colleagues to slow down, Peres has kept a grueling lifestyle.

In an interview with the Associated Press upon assuming the presidency, Peres said that was the only way he knew how to work. "If you are healthy and clear-minded, what's wrong? I'm not in a hurry to pass away," Peres said.