President Bush fainted briefly in the White House residence Sunday after choking on a pretzel while watching a National Football League playoff game on television, White House physician Dr. Richard Tubb said.

The doctor, an Air Force colonel, said Bush quickly recovered and was doing well.

"He fainted due to a temporary decrease in heart rate brought on by swallowing a pretzel," Tubb said. "I do not find any reason that this would happen again."

Bush, 55, suffered an abrasion on his left cheek the size of a half dollar and a bruise on his lower lip, apparently from falling onto the floor from a couch. Bush said he had been feeling under the weather Saturday and Sunday.

"He had not been feeling well the last couple of days," said Tubb, although Bush had exercised rigorously Saturday and had a lighter workout Sunday. Tubb said Bush has felt "a little off his game," as if he was coming down with a head cold.

Bush plans to travel to the Midwest on Monday as planned, White House spokesman Ari Fleischer said. The plan was for Tubb to first give the president a quick checkup to make sure there was no lingering effect from the fainting incident.

Tubb said the episode does not appear to be related to stress or extra work brought on by Bush's duties as commander in chief and the war in Afghanistan. This is the first health scare for Bush as president.

Vice President Dick Cheney has suffered four heart attacks in 25 years and received a pacemaker in June.

The president fainted while alone in a room at the White House residence, watching the Baltimore-Miami football game while his wife, first lady Laura Bush, was in a nearby room on the telephone.

"He said it [the pretzel] didn't seem to go down right," Tubb said in a telephone interview arranged by Fleischer. "The next thing he knew, he was on the floor."

A nurse on duty at the White House was summoned at 5:40 p.m. EST. Tubb was paged eight minutes later. Bush, under his own power, used an elevator to go downstairs to the doctor's office for a complete exam.

Tubb said Bush believes he was out only for a few seconds because when he awoke, his two dogs were sitting in the same position they were when he lost consciousness.

"But the dogs were looking at him funny," Fleischer said.

Tubb said Bush's exam included the use of a heart monitor, and nothing out of the normal was found. His blood pressure and pulse were normal for Bush, Tubb said.

However, the doctor said Bush has a lower-than-normal pulse rate, which doctors attribute to his rigorous workout regime. The pretzel apparently stimulated a nerve, which further slowed his heart rate, Tubb said. That, combined with feeling under the weather, apparently caused the fainting spell, Tubb said.

The medical term for Bush's episode is vasovagal syncope, or vasovagal fainting, Tubb said.

In such cases, the body sends a signal to the heart via the vagus nerve that slows the heart rate enough to cause a brief fainting spell. Among other things, the nerve can be stimulated by fear and intestinal cramps.

It's very common, an emergency room physician said.

"It's thought that pretty much everybody has one simple faint in their life. We see folks every day that have had a vasovagal reaction," said Dr. David Skibbie of Inova Fairfax Hospital in suburban Virginia. "It's alarming, but if everything checks out it's fine and they can go home without any concerns about their future health."

A vasovagal episode isn't the only possibility, Skibbie said. Somewhat less common is cough syncope, where a coughing episode — similar to what Bush reportedly had — can increase pressure in the chest enough to momentarily lower blood pressure. It, too, is benign. Both types of fainting actually can be common among the physically fit because their blood pressure and pulse already are at nice low rates, he noted.

Fainting spells can be brought on by a lack of oxygen caused by choking, but Tubb said Bush's episode appeared be caused by the stimulated nerve.

Bush is not taking any medicine as a result of the episode, the doctor said. Tubb is awaiting results of the sugar levels in the president's blood, but all other tests were complete and showed normal results, he said.

Fleischer contacted reporters shortly after 8 p.m. EST with word of the episode. "At this point, he intends to travel" Monday, the spokesman said.