Aides May Ease President’s Schedule : White House: Doctors say they are satisfied with his progress, but concern about Bush’s pace could affect the plans for a summit with Gorbachev.

WASHINGTON — White House doctors confirmed Tuesday that President Bush has lost 12 or 13 pounds as a result of his thyroid ailment and Administration officials began considering whether the President’s schedule--expected to include two international summit meetings--should be curtailed because of the tiring effects of his treatments.

Providing an update one day after the President appeared gaunt and fatigued and sounded hoarse at a news conference, the doctors said they were satisfied with his medical progress, a White House official reported.

But with U.S. and Soviet officials still hoping to schedule a trip by Bush to Moscow to meet Soviet President Mikhail S. Gorbachev in coming weeks and with Bush planning to attend the annual economic conference of the leading industrial democracies in London in mid-July, White House staff members may have to allow the President more time for rest.

The President received a dose of radioactive iodine on May 9 to slowly destroy his overactive thyroid. He is now taking daily drops of nonradioactive potassium iodide to block production of thyroid hormone. Doctors had determined that the hormone had produced an erratic heartbeat for which Bush was hospitalized for two nights 2 1/2 weeks ago.

Apparently seeking to present an image of a President quickly on the mend, White House officials summoned photographers Tuesday afternoon to the White House horseshoe pit, where Bush--paired with son Marvin against two White House butlers--hit at least one ringer with photographers present.

Such athletics aside, the President’s medical regimen commonly produces the sort of occasional fatigue that he has also demonstrated and the length of his recovery will be unpredictable, said Dr. James Ramey, an endocrinologist and associate clinical professor of medicine at George Washington University Medical Center.

“There’s really no standard. Some people, once their hormones return down to normal, feel better right away,” he said. “But for most people, it can take months,” although those like Bush with relatively mild problems generally experience fewer problems during recovery.

Nevertheless, a slowed presidential pace could complicate the timing and even the conduct of the meeting with Gorbachev. Arms negotiators are attempting to resolve the remaining thorny differences on the Conventional Forces in Europe treaty so that Bush and Gorbachev can meet by the third or fourth week of June with the aim of signing a treaty making large cuts in the two nations’ arsenals of long-range nuclear weapons. The United States has insisted that these differences be resolved before Bush goes to Moscow.

After several embarrassing experiences during the Ronald Reagan Administration, White House officials have grown wary of the risk that a President’s concentration lapses can bring, in the form of crucial mistakes and misunderstandings at major events.

“George Bush with a thyroid problem is like most presidents we’ve had who are normal,” said one friend of the President who has long observed Bush’s penchant for back-to-back meetings, long days on the road and fast-paced exercise. But, he added, “what you’re going to see is a guy who does not have as frantic a pace.”

The President was visited Tuesday morning by four doctors--White House physician Burton Lee III, two cardiologists and an endocrinologist. Deputy White House Press Secretary Roman Popadiuk reported afterward that Bush’s thyroid function, responding to the medication, had decreased to the “low normal” range.

“I got a clean bill of health this morning,” the President said during a picture-taking session at the start of a meeting with members of Congress. He declared himself to be “A-OK.”

Popadiuk said that Bush’s “physicians are very happy with his progress but continue to insist on a slow return to a normal athletic lifestyle.” He said the President has picked up the pace of his exercise walking during weekend visits to Camp David, Md., but has not resumed jogging.

Bush had weighed close to 200 pounds and then lost “12 to 13 pounds” before gaining about 1 1/2 pounds, Popadiuk said.

For most patients, stabilizing the thyroid generally takes from three weeks to three months, Ramey said. But the sort of therapy Bush is receiving--the daily administration of a few drops of potassium iodide, which blocks the thyroid hormone--is designed to bring hormone levels back to normal more quickly.

“It’s not usually done,” Ramey said, “because for most people you don’t have to do it--they’re not President of the United States.”

Bush’s noticeable hoarseness, Ramey added, was probably not caused by his now lowered level of thyroid hormone, as White House officials have suggested.

Instead, Ramey said, Bush’s vocal problems were more likely to be a side-effect of the radiation given to kill his thyroid. The nerve that controls the voice box runs along the outside of the thyroid, he noted, and the radiation can cause the thyroid to swell, producing the vocal problem.