A wise man once said, “Everyone you meet is fighting a battle you know nothing about.” The identity of this savant has been debated, but the quote is most often attributed to the legendary, late comedian Robin Williams. Mike Birbiglia — actor, comedy veteran, likely the most famous man from Shrewsbury, Massachusetts — shares Williams’ trade, but contradicts his sentiment. In “The Old Man & the Pool,” Birbiglia bares all of his battles. The “Sleepwalk with Me” creator presents his latest solo show in Broadway’s Vivian Beaumont Theater. Similar to the aforementioned work, “The Old Man” is a slice of life–style monologue of Birbiglia’s ailments. In a theatrical season full of stories that center on the human body’s knack for disobedience (“Cost of Living,” “Kimberly Akimbo”), “The Old Man & the Pool” presents another fine-tuned brand of self-deprecating humor that makes you feel a little less guilty about laughing at the sick.

The bad news starts with a visit to the doctor’s office. As Birbiglia has aged, these appointments have grown in frequency (and their resulting diagnoses in severity): early-stage bladder cancer when he was 20, diabetes as a new father and now respiratory issues akin to a walking heart attack. At 44, this is concerning given Birbiglia’s less-than-ideal track record and his family’s intergenerational dance with disease: Both his father and grandfather died of a heart attack at age 56. Birbiglia can’t help but journal the morbid prophecy; he thinks “he will die soon.”

There’s a lot more at risk now for the almost-middle-aged comic than during that first clash with a malignant bladder mass. He is husband to Jenny and dedicated father to beloved daughter Oona. So it becomes high time for Birbiglia to right the corroded-artery wrongs of his past and get in some low-intensity cardio. He has to learn how to swim. This would be less daunting a task if some of Birbiglia’s earliest traumatic memories weren’t sprouted at a Worcester, Massachusetts YMCA. But fast-forward a couple decades, nearly 200 miles and a renewed determination to be healthy, and Birbiglia shows up to a Brooklyn YMCA staring down at his reflection in an over-chlorinated pool.

Birbiglia shares all of these anecdotes like an old friend, the uncannily funny one standing at the back corner of a bar and undulating his voice in between sips to mimic everyone else’s drunken behavior. This is not to say that the objects of Birbiglia’s humor are external (the jokes are largely at the deliverer’s expense), but that he is able to zoom out and make quips about his unruly “river corpse” body as if it’s something operating outside him. He peppers the narrative with puns, wordplay and punch lines, never descending into crassness or cruelty to draw laughs from the crowd. To be fair, his audience is a hyper-receptive one. Unlike my guest and me, most attendees were familiar with Birbiglia’s solo works, movie roles and stand-up routines, and showed up ravenous for more. It also helps that Birbiglia’s story centers on an accessible melange of maladies. Cancer, diabetes and heart disease are three of the most common ailments in the U.S.

Aside from the venue, there is nothing inherently theatrical about “The Old Man & the Pool.” The production takes most of its aesthetic notes from traditional stand-up, even honoring the form with a wooden stool. Scenic designer Beowulf Boritt’s simple single set piece — a giant sheet of teal graph paper curved centerstage — symbolizes an entire pool, or a surfable wave. It towers over Birbiglia but also provides a strange form of concave protection as he pours out his soul. Subtle light changes (design is by Aaron Copp) wash the stage in shades of blue, transitioning Birbiglia in and out of his memories. The Beaumont is a sprawling space — last season’s lavish “Skin of Our Teeth” revealed its potential — but the designers of “The Old Man & the Pool” take little creative risk to make use of it. All the more reason to be impressed by Birbiglia’s talent; all that extra space never feels like empty space. Director Seth Barrish has little use for a fourth wall, encouraging his subject to lock eyes with audience members as if they really are in that back corner of the bar.

Cancer, diabetes and heart disease don’t have straightforward cures, but Birbiglia abides by the adage “laughter is the best medicine.” In generously detailing the less-than-ideal fragments of his life, he reveals the many reasons we should keep relishing ours. Apparently, Birbiglia is now a regular at the pool. He seeks new ways to express more love and make Oona laugh. He has a new lease on life and, dare I say, it’s going swimmingly.

“The Old Man & the Pool” opened at the Vivian Beaumont Theater on Sunday, Nov. 13, 2022.

Review photo: Emilio Madrid.

Creative: Written by Mike Birbiglia; Contributions from story consultant Ira Glass; Directed by Seth Barrish; Scenic Design by Beowulf Boritt; Costume Design by Toni-Leslie James; Lighting Design by Aaron Copp; Sound Design by Kai Harada; Projection Design by Hana S. Kim.

Produced by Sue Wagner, John Johnson, Patrick Catullo, Seaview and Center Theatre Group (Michael Ritchie, Artistic Director; Meghan Pressman, Managing Director/CEO; Douglas C. Baker, Producing Director); World premiere produced at the Mark Taper Forum in Los Angeles in 2022 by Center Theatre Group (Michael Ritchie, Artistic Director; Meghan Pressman, Managing Director/CEO; Douglas C. Baker, Producing Director); Following a developmental run at Steppenwolf Theatre Company (Anna D. Shapiro, Artistic Director and David Schmitz, Managing Director).

Cast: Mike Birbiglia.