As he approaches the end of his sixth term as a U.S. senator from Delaware, Joe Biden certainly lends experience to Barack Obama's presidential campaign.

But is the 65-year-old Democratic vice presidential nominee-to-be physically fit to be "a heartbeat away"?

One medical expert says yes, despite his increased risk for suffering an aneurysm.

Biden underwent surgery in 1988 to repair two berry aneurysms on opposite sides of his brain. (A berry aneurysm gets its name because the bulge it creates is so small it looks like a tiny blueberry.)

As long as Biden is checked regularly by his health care providers, and has regular brain CT scans (at least every 1-2 years), he should have a normal life expectancy, Dr. Michael Marin, chief of surgery at Mt. Sinai Hospital in New York City, told FOXNews.com.

“He is probably on medication, but not for the aneurysms. Maybe for blood pressure or that kind of thing,” Marin said. “These aneurysms were diagnosed before he had any events, so he is fine.”

An aneurysm is an enlargement of a normal artery. If an artery has a bulge on its surface – due to genetics or a medical condition such as high cholesterol or high blood pressure – and the artery wall becomes stretched, it can rupture.

However, the causes of berry aneurysms, which are similar to other types of aneurysms, aren’t well known, Marin said.

U.S. Rep. Stephanie Tubbs Jones died Wednesday from a brain aneurysm.

At the time, Marin, who did not treat Tubbs Jones, said she – like most sufferers of brain aneurysms – probably had no warning signs.

But Biden did have warning signs: When the first aneurysm ruptured, he suffered neck pain and nausea. Apparently, the second aneurysm tore without warning signs, but it was repaired a few weeks after the first, and he was back to work at the Senate soon thereafter.

"About 6 million people in the United States are living with a brain aneurysm," said Dr. Marc Siegel, an internist and FOX News medical contributor.

The yearly rate of rupture is about 1 in 10,000 people, Siegel said, and almost half will die as a result of the rupture.

Click here to read more from Siegel on aneurysms.

"There are two ways to fix an aneurysm when it is detected early," Marin said.

One way is to surgically open the brain and secure the aneurysm at its base with a metal clip.

The second and more desirable way is to pack the aneurysm with small, flexible wire coils that are inserted into the aneurysm using a catheter, which is inserted through the groin, Marin said.

Often, even if a person catches the aneurysm early and the doctors have a chance to treat it, the person can still be left with stroke-like side effects. This was not the case with Biden.