Rick Rycroft/Associated Press Olga Kotelko competing in the Masters Games in 2009. She holds 26 world records.

No one would mistake Olga Kotelko for one of the Olympians competing in Sochi, Russia, but at age 94, she holds more world records than most: 26, to be exact, including age-group bests in the high jump, the hammer throw and the 200-meter run. Not bad for someone who took up track and field at age 77.

Bruce Grierson met Ms. Kotelko in 2010 while writing about her for The New York Times Magazine, and swiftly became obsessed. His interest was personal. The title of his previous book, “U-Turn: What If You Woke Up One Morning and Realized You Were Living the Wrong Life?,” might also describe his mind-set at the time. He was 47 and had abruptly realized that he could no longer see his feet beneath his growing potbelly. His stamina, drive, memory, even the hair on his head, were disappearing, too.

“Whatever was happening with her,” he writes in the prologue of his latest book,“was the opposite of what was happening to me.” If he could identify the reasons she was aging so well, perhaps he could reset his own course.

Eventually, they struck a deal: “We would explore the mystery of her together. She would offer herself up to science while I took notes.” The result is this jolly book, which follows the pair as they consult researchers in fields like gerontology, exercise physiology and genetics for insights into Ms. Kotelko’s remarkable youthfulness.

What they find are countless opinions, but little definitive proof. Genes, diet, temperament, the theories abound. (Mr. Grierson rules out performance-enhancing drugs.) Or maybe it’s the exercise itself.

Research on twins suggests that heredity accounts for only about 25 percent to 30 percent of longevity, so it is not enough simply to label Ms. Kotelko a “genetic freak.” Besides, tests show she lacks at least one gene associated with longevity, and it turns out that her telomeres, chromosome caps that shorten with age, are merely average in length.

As for her diet, it is abundant and promiscuous. Her staples include red meat, sauerkraut, cottage cheese and sour milk, and she eats “immoderate amounts” of tapioca pudding. A centenarian friend of hers, the Australian shot-putter Ruth Frith, eschews vegetables altogether.

Ms. Kotelko’s kitchen contains a few promising items (probiotic bacteria in her beloved fermented foods might bolster her immune system; zinc in the beef and nuts she devours could possibly offer some protection against Alzheimer’s disease). But readers looking for dietary tips will find little satisfaction here.

Among the potential anti-aging elixirs Mr. Grierson explores, exercise appears most potent. This old standby doesn’t just keep hearts pumping and muscles strong; studies suggest it may protect the mind, too, by promoting the formation of neurons in the hippocampus — a part of the brain associated with memory. “For building cognition, Sudoku is a shovel, and exercise is a bulldozer,” Mr. Grierson writes.

Since she began her track and field career, Ms. Kotelko has rarely remained still, and that active lifestyle may be more important than her workouts at the track. “Both Olga and I exercise, but she moves when she’s not exercising, and I don’t,” Mr. Grierson writes. “Olga is older than I am. But 95 percent of the time, I am getting older faster than she is.” Burgeoning research on the inactivity epidemic suggests that one important habit he could acquire is standing up.

The book concludes with a tidy list of “rules for living.” The nine maxims, which include “keep moving,” “believe in something,” “don’t do it if you don’t love it” and “begin now” — convey nothing that a consumer of health news and popular psychology hasn’t already heard a million times. Perhaps that’s the point.

For now, the best anti-aging tools science can offer are habits we already know we should be doing, but perhaps, like Mr. Grierson, are not: exercising regularly, sleeping enough, limiting sedentary behavior and maintaining meaningful social connections. To his credit, the author does not oversell the still-unfolding science of aging, and he’s quick to acknowledge that a single example cannot explain why some people age better than others.

While this book provides an accessible overview of the current science on aging, its charm comes from the tale of a woman who refuses to hang up her track shoes, and the younger man she inspires to stop acting so old. In one of the book’s most engrossing chapters, Mr. Grierson decides to enter the 10,000-meter run (6.2 miles) at the 2011 World Masters Athletics competition in Sacramento, Calif. He runs “like a hairy goat” and finishes second to last, but he gains an important insight: These competitions are about the camaraderie.

“Comfort doesn’t promote togetherness,” he writes. “Discomfort does.” Strong social ties track with longevity, and the confidence derived from finishing a race probably doesn’t hurt either.

Ms. Kotelko turns 95 next month. No one would blame her if she chose to rest on her laurels; instead she’s looking forward to chasing more records when she enters the next age group, 95 to 99.

I finished this quick read on my birthday, after cross-country skiing my age in kilometers. Since I began this annual tradition in my early 30s, people have asked me at what age I will quit. This book convinced me that the answer is “never.”