Another cardiologist, Dr. Stephen Plantholt of St. Agnes HeathCare, resumed jogging after receiving two stents this year to clear clogged arteries. Plantholt, who is 51, suspected he had a problem when he noticed he was becoming short of breath during exercise. His suspicions were also raised by the fact that several relatives had suffered heart problems in their 50s.
Though two of the recent deaths seemed to have come without warning, doctors say middle-aged men and women should seek medical attention if they notice the subtlest symptom.
"Some just tough it out," said Dr. Mark G. Midei, a cardiac surgeon at St. Joseph Medical Center. "It's hard to imagine running a marathon at world-class speed with a blockage ... but I've known people who have done it."
The deaths, however, show how difficult it can be to know when a person is truly in danger.
David Nagey, who died at 51, had never had any symptoms before he collapsed during the fund-raising race, according to his wife, Elaine. But he was aware of his risk. His father had died while jogging when he was 56. And his paternal grandfather died of a heart attack at 59.
Mindful of this, he had regular physicals and took medication to lower his cholesterol.
Normally optimistic, Nagey had talked about the possibility of meeting the same fate as his father and grandfather. "But I don't think he was willing to become a cardiac cripple," his wife said. Though he hated to drive, Nagey loved his work so much that he logged 38,000 miles last year crisscrossing the state to treat women with high-risk pregnancies. He jogged to keep in shape and enjoyed sailing.
When he collapsed, a doctor who was running alongside him tried but failed to resuscitate him. Though no autopsy was done, doctors assumed he died from a heart attack.
Today, Elaine Nagey says she is astonished by the number of friends and colleagues who have lost their middle-aged husbands and brothers to heart attacks.
"Right here where I work, I can look around and see five people touched by sudden cardiac death," she said. "It's creepy."
Bruce D. Cornbrooks, an insurance executive and lifelong athlete who played tennis and jogged, began noticing last winter that he wasn't running well. He tired faster than usual and had to stop periodically to catch his breath.
Cornbrooks, who was 53 and lived in North Baltimore, sensed that he had a heart problem, though he had no family history of it. Doctors with St. Joseph Medical Center in Towson discovered a clogged artery and inserted two stents.
"The doctor was just shocked that Bruce didn't die while jogging," said his wife, Nancy Cornbrooks. "He thought that one more jog would have done it."
After surgery, his doctor suggested he stop jogging and take up walking as a less stressful form of exercise. But he continued to feel discomfort in his chest. On Oct. 3, Cornbrooks returned home from an hourlong walk and, after remarking that he felt poorly, suffered a fatal heart attack.
Nancy Cornbrooks said she cannot blame jogging for anything that happened.
"If he had never been jogging, he would never have known anything was wrong," she said. "What really surprised me was that you could be that close to something being wrong with you and feel no other symptoms."
His cardiologist, Dr. Nancy Strahan, said she is becoming convinced that jogging is potentially dangerous for middle-aged adults.
"Before I tell a middle-aged person to jog at this point, I'll tell them to have a full assessment of their risk factors," Strahan said. Anyone with significant risks or symptoms should have an ultra-fast CT scan and possibly a stress test, she said.
Whether the test would have helped James L. Lears Jr., a well-known runner who died of a heart attack last month after an evening jog, perhaps can never be answered. His wife, Catherine Lears, said he had annual physicals that included cholesterol tests and an electrocardiogram, which traces the heart's rhythm. But she doesn't recall him taking any of the newer tests.
She said his death, at 55, came completely without warning, in the basement while he was doing laundry. An autopsy revealed that he had a 90 percent blockage in one artery.
Lears, a tax adviser, ate right and neither smoke nor drank. He ran six to eight miles a day, apparently without symptoms, and competed in marathons in Boston and Baltimore.
Montz's death is perhaps most puzzling of all. The ponytailed surgeon, who treated women with gynecologic cancers, collapsed and died Nov. 21 while jogging near his home in Poplar Hill. He was 47.
"His vessels were clean - there was no evidence of heart attack," said his wife, Dr. Kathleen M. Ryan, an obstetrician and gynecologist. Instead, doctors performing the autopsy suggested that he died of a sudden irregular heartbeat.
His wife said she may never know what caused the problem. In some cases, a tiny structural defect in the heart can cause electrical signals to go awry. Some runners have also been known to develop an enlargement of the heart's lower chamber, which itself can trigger an electrical glitch.
What motivated him to run, however, was never in doubt.
"It was part of his healthy lifestyle," she said. "It was also a great time to be by himself and think. Mind, body and spirit."