When Nyad premiered on Netflix in November 2023, it introduced audiences to a story of extraordinary determination—a marathon swimmer’s quest to conquer a 110-mile open-ocean journey from Cuba to Florida at the age of 60. But behind the scenes of this biographical sports drama, another feat of endurance was taking place: the remarkable physical transformations of its leading actresses, Annette Bening, 65, and Jodie Foster, 60, who whipped themselves into shape to portray real-life figures Diana Nyad and her coach Bonnie Stoll. Their commitment to authenticity not only brought the story to life but also challenged Hollywood’s ageist stereotypes, proving that women in their 60s can be as fierce and formidable as any athlete—or actor—half their age.

Directed by husband-and-wife team Elizabeth Chai Vasarhelyi and Jimmy Chin—known for their Oscar-winning documentary Free Solo (2018)—Nyad marked the duo’s first foray into narrative filmmaking. The film, based on Diana Nyad’s 2015 memoir Find a Way, follows Nyad’s relentless pursuit of a dream she first attempted at 28: to swim from Havana to Key West without a shark cage, braving sharks, jellyfish, and brutal ocean conditions. After failing in her youth, Nyad returned to the challenge in her 60s, ultimately succeeding in 2013 after four grueling attempts over four years. Bening stars as Nyad, embodying her unyielding spirit, while Foster plays Stoll, her best friend and coach, who provides the emotional anchor for the journey. The film premiered at the Telluride Film Festival in September 2023, hit select theaters on October 20, and began streaming on Netflix on November 3, earning critical acclaim and Oscar nominations for both actresses in 2024.

For Bening and Foster, the roles demanded more than emotional depth—they required a level of physical preparation that pushed their bodies to new limits. Bening, a four-time Oscar nominee for films like American Beauty (1999) and The Kids Are All Right (2010), knew from the start that portraying Nyad would be a monumental challenge. Nyad’s swim, often called the “Mount Everest” of open-water swimming, spanned 53 hours and 110 miles, requiring immense stamina and resilience. To authentically capture this, Bening embarked on a year-long training regimen under the guidance of former Olympic swimmer Rada Owen, who competed in the 2000 Sydney Olympics. “My God. What am I going to do?” Bening recalled thinking in a Vanity Fair interview, describing a “come-to-Jesus moment” as the reality of the role set in.

Bening’s training was nothing short of grueling. She began with the basics—learning Nyad’s unique strokes and kicking techniques—before building up to swimming eight hours a day, often in a 233-by-233-foot water tank off the Dominican Republic coast where much of the film was shot. “I’d have liked to have been in the ocean more,” Bening told the Los Angeles Times, noting the logistical challenges of filming on water. Her dedication was evident on set, where she insisted on performing her own swimming scenes, refusing stunt doubles to ensure the strokes were unmistakably hers. “You’d be able to tell that the stroke wasn’t mine,” she explained, a testament to her commitment to authenticity. Nyad herself praised Bening’s effort, noting at a Los Angeles screening that the actress swam so convincingly that professional swimmers couldn’t tell she wasn’t one of them. “She swam some days [for] eight hours a day,” Nyad said, adding, “You did it, girlfriend.”

The physical transformation was profound. Bening, who started with a slender, yoga-fit frame, packed on slabs of muscle, particularly in her shoulders, to emulate Nyad’s heavy endurance build. “My jackets fit differently,” she told Bonnie Stoll, as reported by The Washington Post. Even after filming, Bening continued swimming, telling The Hollywood Reporter in November 2023, “I’m a better swimmer now than even when I made the movie… It has changed my life.” She spoke of the sport’s impact on her brain and soul, describing how it relaxes the central nervous system—a sentiment that resonates with Nyad’s own philosophy of finding peace in the water, despite her famously un-mellow personality.

Jodie Foster, a two-time Oscar winner for The Accused (1988) and The Silence of the Lambs (1991), underwent her own rigorous preparation to play Bonnie Stoll, a former racquetball champion turned personal trainer. Stoll, 71 at the time of filming, maintained an intense fitness regimen—100 reps daily of shoulder, biceps, and ab exercises, two-hour power walks, and military-style chin-ups. To embody this “iron woman,” as described in Variety, Foster dedicated months to training with weights and kettlebells, alternating heavy lifting with a strict diet of brown rice, chicken, and broccoli. Her goal was not just to look the part but to channel Stoll’s “salt-of-the-earth quality,” as she told Netflix Queue. Foster, who hadn’t been Oscar-nominated since 1995, earned a Best Supporting Actress nod for her “fierce, strong, and heartfelt” performance, with critics like Leonard Maltin noting that her chemistry with Bening “didn’t seem like acting at all.”

Foster’s transformation was striking. On her first day on set, directors Vasarhelyi and Chin were jolted by her physicality—her “titanium guns” and radiant confidence, as Variety put it, made her a buoyant presence. “She’s the kind of person you’d want to be in a storm with,” Foster said of Stoll, a fitting description given the film’s dramatic storm sequences, one of which saw Foster enduring dump tanks of water while refusing a body double. Her commitment to showing older women as “badasses,” as she told the directors, aligned with the film’s broader message: aging is inevitable, but weakness isn’t. “We don’t have to lose our muscle,” Stoll’s character says, a line that echoes Foster’s own philosophy at 60, a milestone she described in a Women’s Health interview as a time to support others rather than compete with her younger self.

The physical demands of Nyad were only part of the challenge. Bening and Foster also had to navigate the emotional complexity of their characters’ relationship—a deep, hard-earned friendship between two queer women in their 60s, a dynamic rarely seen in Hollywood. Bening’s Nyad is portrayed as ferociously single-minded, often abrasive and self-obsessed, a trait that makes her a formidable athlete but a difficult friend. Foster’s Stoll, by contrast, is the grounding force, balancing toughness with kindness. Their chemistry, described by Collider as “unmatched,” brought to life a female friendship built on love, trust, and mutual support, a refreshing departure from the competitive dynamics often depicted on screen. “They completed each other,” Foster said at a press conference, emphasizing the power of chosen family—a theme she connected with as a gay woman herself.

Yet, Nyad is not without its controversies, which add a layer of complexity to Bening and Foster’s performances. While the film presents Nyad as a heroic figure, her 2013 swim has been questioned by the marathon swimming community, leading to its formal recognition being stripped by the Guinness Book of World Records. Critics like Steve Munatones, a former advisor on the film, faced pushback for trying to ratify the swim, highlighting tensions within the sport. Nyad’s elite media connections and past exaggerations—like falsely claiming to be the first woman to swim around Manhattan—have fueled antagonism, as noted in Time. The film largely sidesteps these issues, focusing on Nyad’s personal triumph, a choice that some, like Variety, argue makes her a challenging protagonist: “She’s entitled, mean, self-centered… and she’s our hero?”

Bening and Foster’s performances navigate this complexity with nuance, humanizing Nyad without glossing over her flaws. Bening’s “body-and-soul acting,” as Variety called it, captures Nyad’s vulnerability beneath her bravado, particularly in scenes addressing her childhood trauma, including sexual abuse by her swim coach—a detail Nyad herself has been reluctant to discuss publicly. Foster, meanwhile, brings warmth and authenticity to Stoll, a role the real Bonnie praised, telling Sky News, “I definitely thought it was me… It’s surreal and unbelievable.”

Ultimately, Bening and Foster’s transformations for Nyad—both physical and emotional—challenge Hollywood’s narrow definitions of what women in their 60s can achieve. Their rigorous training, from Bening’s eight-hour swims to Foster’s weightlifting regimen, not only honored the real-life athletes they portrayed but also delivered a powerful message about aging, resilience, and the intersection of athleticism and acting. As Nyad continues to resonate with audiences on Netflix, the actresses’ dedication stands as a testament to their craft—and a reminder that greatness knows no age limit.