Strained retirement benefits, swelling healthcare costs, a national savings rate below zero — aging in America has become increasingly tricky. But in Congress, getting older is a boon.

Benjamin Franklin once said, “Life’s tragedy is that we get old too soon and wise too late.” Today’s lawmakers leave nothing to chance and stay in Congress until they are really, really wise.

The median age of members of Congress is nearly 20 years higher than that of their constituents, but lawmakers thrive on perks that only seniority can bring. From committee chairmanships to prime office space, the world of Capitol Hill opens with longevity.

That doesn’t mean they are immune to some of the drawbacks of advancing age. Stress, night flights back to distant districts and 7 a.m. briefings can take their physical toll. And come election time, there is sure to be an aggressive challenger whispering that an aging incumbent’s mental capacity is diminished.

Sen. Robert Byrd (D-W.Va.) has beaten back “ageist” sentiment since he first hit the Social Security roster in President Reagan’s first term. The 87-year-old, who walks with the help of a polished wooden cane and works through periodic hand tremors, says the graying of the U.S. population has sparked fresh appreciation for how much senior citizens can contribute to public life.

“What a resource senior citizens can be!” Byrd remarked by e-mail. “Copernicus was 70 when he argued that the sun, not the Earth, is the center of the cosmos. Grandma Moses was in her 70s when she started painting. Claude Monet painted his famous water lilies at 74. Former Senator John Glenn ventured back into space at the age of 76.”

Despite Byrd’s impressive list, politics can age people quickly while the public watches. Presidents Bush and Clinton both spent their first terms acquiring silver hair and weather-lined faces so that, after four years, they looked very different from their pre-White House selves.

Still, members reject the idea that the daily grind of lawmaking accelerates aging.

“I don’t think this ages you any more than any job you’d have in the real world,” said Rep. Mike Simpson (R-Utah), 55. He should know, having spent more than 20 years drilling root canals as a dentist before getting elected. “You still have the same types of pressures. The only thing [stressful] about this job is that you have to ask to be reelected every two years.”

Dr. Don Royall, professor of geriatric psychiatry at the University of Texas’s San Antonio-based health center and a leading voice on longevity issues, echoed Simpson’s opinion.

“People in Congress tend to be among the most highly educated, affluent, health-insured and fortunate people in the U.S. In general, those sorts of factors favor cognitive function,” Royall said.

He studied cognitive function in retired Air Force generals, whose level of responsibility and job stress is similar to that of legislators. Though their lifestyle of public service prepared them well for the challenges of aging, Royall found that the generals’ mental acuity was not enough to prevent them from losing so-called executive function — the ability to set goals, then start and finish them.

Executive faculty “turns out to be a better predictor of functional status than a lot of medical problems that the elderly get into,” Royall said. So Byrd’s cane is probably less relevant than his sustained ability to fire off detailed floor speeches.

Royall is more skeptical of the judiciary’s capacity to stay sharp. “I’ve wondered what would happen if you gave members of the Supreme Court these measures of executive function,” he mused. “It would probably be scary.”

Many on the Hill feared for the late Sen. Strom Thurmond (R-S.C.) as he hit triple digits while remaining in office. Thurmond, who served in the Senate for 48 years, was obliged to scale down his duties as president pro tempore during his final term. He required the help of an aide to accomplish even the simple task of rising from his chair and died just six months after his career in Congress ended.

Similarly, former Sen. Jesse Helms (R-N.C.) maintained his active pace throughout the onset of peripheral neuropathy, an affliction of the nervous system that left him without feeling in the soles of his feet. Helms kept walking through the Capitol’s marble halls until the age of 81, almost 30 years after he arrived.

Average U.S. life expectancy in 2003 was 77.6 years, according to the Centers for Disease Control and Prevention.

Rep. Rick Boucher (D-Va.), in his 12th term, parried the question of whether time in Congress heightens the difficulties of aging. “How old would you say I am?” he asked. When this reporter’s guess fell just one year shy of Boucher’s real age (he’s 59), he shared his personal secrets about how to avoid physical decline.

“It’s hard. This job requires a lot of hours. But if you enjoy what you’re doing, work promotes health,” Boucher said. Aside from preserving his motivation, Boucher jogs, bicycles and always takes the stairs instead of hopping a Capitol elevator. He also sticks to nutritious food, shunning desserts at congressional receptions.

Rep. Don Sherwood (R-Pa.) has been in office for only three terms but is five years old than Boucher and is ambivalent about aging and governing simultaneously. “I can certainly understand how the presidency would age somebody,” he said.

As for members of Congress, he was circumspect. Rank-and-file members, Sherwood said, avoid some of the stress that congressional leaders endure. “Leadership jobs are tougher on people than some of the rest of us,” he said. “They go night and day all the time. We have a little time to catch our breath.”

But that downtime could turn out to hasten the effects of aging by requiring more cognitive readjustment, according to one of Royall’s fellow longevity scholars. M. Powell Lawton of the University of Michigan found that relaxation can harm mentally active older people as much as their daily routine, Royall said.

“For people at the highest levels of cognitive capacity, they can be stressed by too much or too little stress. Too little! It’s the typical story of the executive who can’t stand vacations,” Royall said.

Members might stay young at heart by running to late-night quorum calls, but another class of congressional employees often heads home feeling far older than their years.

“It might age your staff more than it ages you,” Simpson observed with a rueful glance.