Last winter, 99-year-old Ruth Halloran broke a femur, which led to her first hospital care since the birth of her youngest child 60 years earlier.

“Mother had all original parts . . . no pacemaker, no valves, no hips, knees, or bypasses,’’ said her daughter, Elaine Ford Arama of Los Angeles.

Mrs. Halloran’s son, Paul Ford of Atlanta, said the doctors who treated his mother’s leg compared her bone density to a woman in her late 40s. “She had very good bones,’’ Ford said. “And mentally, she was sharper than anyone.’’

Although she had little need for hospitals, Mrs. Halloran’s health had been closely monitored. She was an original participant in the Framingham Heart Study, the continuing project credited with identifying common factors that contribute to cardiovascular disease.

Mrs. Halloran, who died in her Nashua, N.H., home Jan. 31 at 100, was one of the longest-lived members of the study, which she voluntarily and proudly participated in for 67 years without ever missing an exam. That devotion, as well as her longevity and good health, were particularly useful to cardiovascular research, study staff said.

“Her dedication was profound,’’ Maureen Valentino, the study’s recruitment manager, said of Mrs. Halloran’s commitment. “She never said no to anything we asked.’’

Mrs. Halloran had a neurology exam at her home last year and visited the study’s Framingham offices herself for her last major heart exam in 2012. Her son and daughter are also participants in the generational study.

The Framingham Heart Study was just one of Mrs. Halloran’s many efforts as a volunteer. She was deeply involved in civic organizations, including the American Red Cross, the United Way, and the Girl Scouts of America. She also helped organize a group of teenage volunteers during World War II, her daughter said.

Mrs. Halloran’s work for the Red Cross, which began during World War II and lasted through the Vietnam War, included notifying military personnel of births, deaths, and emergencies that had happened at home while they were away. She did that by telex at all hours, her family said.

Her daughter recalled hearing Mrs. Halloran dictate telex messages in the middle of the night. “Knowing how time-sensitive these matters were, she never waited until morning to complete an alert,’’ Arama said.

Ruth Van Ness was born in Boston in 1915 and grew up in West Roxbury, the oldest of five daughters. Her parents were Benjamin Van Ness and the former Ora Crandall.

Mrs. Halloran’s ancestors arrived in the United States in the 1640s, her family said. The Van Ness side lived in the Dutch settlement of New Amsterdam on the tip of what is now Manhattan, N.Y., while her maternal ancestors lived in Massachusetts and then in Rhode Island.

Like Mrs. Halloran, many of her ancestors lived well into old age. She was 78 when her mother died at 103.

After graduating from Simmons College and what is now the University of Massachusetts Boston, Mrs. Halloran was a teacher at East Boston High School. At age 24, she and a girlfriend drove to California and back.

In 1942, she married Martin Ford and they settled in Framingham. She stopped teaching because at the time, many schools and school districts did not allow married women to work full-time as teachers. For 15 years, she was a substitute teacher in Framingham.

Mrs. Halloran’s father was a builder and she had a keen interest in his work. She inherited his tools when he died, said Arama, who recalled watching her mother change light switches and fixtures “in the blink of an eye.’’

Martin Ford died in 1972, and two years later, she married Mark Halloran, who died in 1995. His daughter, Jeanne Boisseau of Melrose, called Mrs. Halloran “the most wonderful, inspirational woman,’’ and said that when the family got together to play Trivial Pursuit “we all would fight to get Grandma on our team.’’

Mrs. Halloran “was busy all the time, never wasted a minute’’ and “never forgot a birthday,’’ Boisseau said. On the day after Mrs. Halloran died, Boisseau’s daughter received a birthday card that Mrs. Halloran had mailed two days earlier.

Mrs. Halloran enjoyed performances at Symphony Hall and was a dedicated swimmer until three years ago, said her son, who had watched his mother in the waters off Truro, “bobbing up and down in her swim cap with daisies on it.’’

A leader of Girl Scouts at all levels, Mrs. Halloran loved the outdoors.

“Ever the teacher,’’ her son said, “she was always taking us on long walks through the woods, where she would point out which plants and trees were medicinal, and which we should never pick because they’re endangered.’’

In Nashua, where she moved with her second husband in 1977, Mrs. Halloran taught English to group of Korean neighbors, and volunteered at a hospital gift shop. She also played Jeopardy and Scrabble and finished crossword puzzles regularly.

“She was always fun, right to the end,’’ said her son, who added that Mrs. Halloran “liked a good dinner out, enjoyed a cocktail, and loved dessert.’’

Mrs. Halloran chose not to have a funeral. In addition to her son, daughter, and stepdaughter, she leaves two stepsons, Mark of Plymouth and John of Kingston, N.H.; two sisters, Alberta Morrison of Charlton and Jeanne Yanko of Bellingham, Wash.; 12 grandchildren; and seven great-grandchildren.

In her Framingham neighborhood, Mrs. Halloran was well-known for the vintage Flexible Flyer sled upon which she coasted down a nearby hill, often with children piled aboard with her, and all while wearing her fur coat.

“None of the other mothers ever went outside to try even a single run, but my mother would be out there all afternoon, marching up the hill, orchestrating belly bump triple-deckers and sled trains,’’ Arama said. Mrs. Halloran arranged contests among the children and strategized who should board which sled to maximize speed.

“Mom was always thinking, always having fun,’’ Arama said, “and always sharing what she’d learned.’’

Kathleen McKenna can be reached at kmck66@verizon.net.