Each Thursday, Dr. Walter Ehrlich can be found along busy 41st Street in Roland Park, surrounded by signs protesting excessive war and expressing concerns about climate change. The 100-year-old regularly talks with family on Skype, sends emails, and recently learned to use the Uber transportation app.
Ehrlich is among a record number of centenarians in the United States. The number of Americans who celebrated 100 years or more of life increased more than 43 percent from 2000 to nearly 72,200 in 2014, the latest year for which data is available, according to a recent report from the U.S. Census Bureau.
Studies have shown common factors — such as Ehrlich's active lifestyle and ability to connect with the modern world — may increase a person's chances of such a long life.
Many centenarians come from families who live a long time, indicating that there is a genetic component, research shows. Living a healthy lifestyle that includes regular exercise, balanced meals and no smoking also can increase the odds of a long life, studies have found.
Health experts say other factors in the rise of the number of 100-year-olds include safer workplaces — people aren't working in as many dangerous jobs — and medical advancements against once-deadly infections and other illnesses. One of the most significant factors is that fewer people are dying from heart disease — the No. 1 cause of death in the U.S.
Jeremy Barron, medical director of the geriatric medicine outpatient office at Johns Hopkins, said treatment has improved so much that cancer is expected to eventually surpass heart disease as the leading killer of older people.
The trend also has consequences. An aging population puts added pressure on families, the health care system and other parts of society. Researchers and geriatrics specialists are working to better understand this impact.
"Having so many people grow too old at one time is entirely new to us, and we have a lot of learning left to do," said Renee S. Fredericksen, a specialist on aging who sits on the executive council of AARP Maryland.
About 1,800 Maryland residents are 100 or older, according to the Maryland Centenarians Committee Inc., which tracks that population using Social Security data. The group has held a celebration for centenarians every May since 1993.
The group also has asked these senior citizens about the keys to a long life. The responses varied: Some attributed their longevity to spirituality, while others said they remained single and avoided the stresses of marriage and raising children. Some ate healthfully, and others said they drank a glass of wine every day.
The graying of America has spurred the growth of industries to meet their needs. Senior travel groups and housing communities cater to the elderly, and health care providers are tailoring services for them. This summer, St. Agnes Hospital became the second in the state to open a separate emergency room catering to seniors. Holy Cross in Silver Spring opened what was considered the nation's first senior emergency care center in 2008.
The health conditions of centenarians also vary; some need extensive care and suffer from chronic conditions, while others live independently in their own homes or in retirement communities.
"I think the longevity explosion we are having is a double-edge sword," said Carmel Roques, president and CEO of Keswick Multi-Care Center community for seniors. "We do everything we can to prolong people's lives. But it also has a downside, which is lots and lots of older adults with chronic illnesses."
Some of these people end up in nursing homes, but others wind up under the care of relatives, including sons and daughters who also are themselves elderly and dealing with declining health.
"We now have people in their 70s and 80s taking care of parents," Fredericksen said. "It can be hard on families."
"For the most part, the older we become, the more intense the need for care in our daily lives becomes — from help getting dressed, cleaning, eating and managing our finances," Fredericksen said. "We slow down, we become frail, and medical incidents happen more frequently at an older age than a younger age."
Some older people must learn to live on their own as the years stretch on, which can lead to isolation and mental health problems, specialists on aging said.
"The hardest thing for most of them is that so many of the people who were in their lives are dead," said Odessa D. Dorkins, the founder of the Maryland Centenarians Committee Inc. "It can be very lonesome for them to outlive their friends, outlive their family and outlive their spouse."
At Roland Park Place retirement community, where Ehrlich and five other centenarians live, the staff tries to provide residents "social interactions and the ability to make new friends and don't feel lonely or isolated," said Becki Bees, director of marketing for the facility.
Barron, of Johns Hopkins, said getting seniors more involved could benefit society as well.
"There are a lot of older people who would like to be engaged in the community and giving back in terms of working, volunteering or mentoring," Barron said. "I think there is a lot of opportunity for older people to help society that we are not taking advantage of. When older people are involved in meaningful activity, it improves their quality of life."
Ehrlich, a Czechoslovakian-born veteran who was wounded as a soldier and tank driver during World War II, half-jokes that he probably should have died many times before.
The retired medical doctor and physiologist says he has been lucky, but he recognizes he is slowing down. He wears hearing aids and has to keep his legs propped up because of circulation problems. He suffers from macular degeneration and carries around a magnifying glass to read. A special machine magnifies the print of the several newspapers he reads each day.
This past weekend, he lost his second wife, who was 83.
Ehrlich said there are still many things he enjoys about life. He follows politics and looks forward to a mayoral debate that will be held at Roland Park Place soon. He goes to the theater and never misses his weekly protest. On his 100th birthday, he didn't want a big party. Instead, his three children came over to spend time with him.
Ehrlich said he doesn't mind aging, "as long as I can enjoy life and see my children."
Jack Slaughter, 102 and also a resident of Roland Park Place, said he doesn't want to be a burden to his three children. His wife of 74 years died two years ago, and he has had to adjust to living by himself.
The Navy veteran and former real estate agent has outlived many of his friends. There are only three people alive from his Naval Academy class. He doesn't think they'll have a reunion.
He spends a lot of time on the computer and still cooks for himself — his specialty is fried eggs. He used to walk a couple of miles a day but now goes about a half-mile a day using a walker.
But his health is good. The only medication he takes is a diuretic for swelling in his legs.
"I think I'm doing OK for an old man," he said.