(Weinstein Books)

When someone mentions Dick Van Dyke, the first image that pops to mind is probably the actor in motion: making pratfalls across the living room he shared with Mary Tyler Moore on “The Dick Van Dyke Show” or shuffling like a penguin in a candy-cane-striped blazer in “Mary Poppins.” One of his greatest gifts as a performer has always been his ability to stretch his lanky body in ways that look graceful and funny.

In his new book, “Keep Moving,” Van Dyke says that gift — specifically, his ability to dance — has kept him young and still vigorous at nearly 90. (He’ll celebrate that milestone birthday in December.)

“If I am out shopping and hear music playing in a store, I start to dance,” he writes. “If I want to sing, I sing. I read books and get excited about new ideas. I enjoy myself. I don’t think about the way I am supposed to act at my age — or at any age.”

“Keep Moving” — a follow-up of sorts to his 2011 autobiography, “My Lucky Life In and Out of Show Business” — is filled with similar advice about how to think and feel young well into a person’s senior years: Be curious, travel, eat light but also treat yourself to dessert at the end of each day. None of it is earth-shattering, and at times, Van Dyke, who collaborates here with celebrity scribe Todd Gold, repeats ideas using only slightly different words. But there’s something so amiable and incurably optimistic about Van Dyke’s attitude that one can’t help but be inspired by portions of this memoir-meets-self-help hybrid.

At age 40, Van Dyke recalls, he was told by a doctor that he had such severe arthritis that he probably would be in a walker or wheelchair within five to seven years. His response? “I lit into a dance, as if proving to myself I could still order my body to do a soft shoe anytime I wanted, despite the pain in my leg.” He also recounts how, more recently, he recovered from pneumonia and multiple lung collapses because his wife and family “encouraged me to get back to the things I loved to do, which I think is the key to recovery.”

Dick Van Dyke at the 19th Annual Screen Actors Guild Awards at the Shrine Auditorium in Los Angeles in 2013. (Photo by Matt Sayles/Invision/AP/ )

He writes extensively and lovingly about his wife, Arlene, who happens to be 46 years his junior, an age gap that, he says, understandably elicits gasps and questions about what they could possibly have in common. “What does anyone talk about with his or her best friend?” he says in response. “We talk about everything. Everything.”

But the real highlight of “Keep Moving” is the chapter that features an extended conversation about aging between Van Dyke and Carl Reiner, 93, who created “The Dick Van Dyke Show.” Although Reiner may have partly based Van Dyke’s character on himself, the (slightly) older comedy legend definitely differs from his friend on the subject of The End. When Reiner says he has been seeing a therapist for years, Van Dyke asks, “After all these years, what are you still working on?

“CARL: Anxiety.

“ME: What is causing your anxiety?

“CARL: Dying.”

The author, on the other hand, says he doesn’t think about death at all. The real Dick Van Dyke, apparently, won’t sit still long enough to let the Grim Reaper dance anywhere near him.

Jen Chaney is a pop culture critic and author of the new book “As If!: The Complete Oral History of ‘Clueless.’ ”

Keep Moving
And Other Tips and Truths About Aging

By Dick Van Dyke

Weinstein. 239 pp. $25.99