A big reason why movies about athletes doing extreme things are often effective is that they depict a mindset most of us can’t even imagine. Nyad is the latest example. The story dramatizes the efforts of Diana Nyad to swim from Cuba to Florida. Why would anyone want to spend more than two straight days swimming 110 miles under brutal conditions? The answer, of course, is that it was her dream. You could be forgiven for thinking it’s an insane thing to do, but to the film’s credit, you become a believer for two hours.

Whereas most biopics include footage of the real people at the end, Nyad includes it at the beginning, giving viewers a look at the famed swimmer’s failed 1978 effort to make the Cuba-to-Florida trek. Then we meet her at age 60. Played by Annette Bening, she has settled into a way of life that may be too quiet for her. Then the idea strikes to take another stab at the swim. She convinces longtime friend Bonnie Stoll (Jodie Foster) to be her coach, and they hire an expert nautical navigator, John Bartlett (Rhys Ifans), to help her chart a course. Several unsuccessful attempts make the idea seem even crazier than it did before.

Nyad was directed by Jimmy Chin and Elizabeth Chai Vasarhelyi, whose documentaries The Rescue and Free Solo harrowingly detail people doing seemingly impossible things. They smartly put a strong emphasis on the many, many hurdles Diana Nyad faces – exhaustion, nausea, hallucinations, swallowing sea water, jellyfish and sharks, skin damage from the water, and so on. You might not have realized what a punishing undertaking a massive swim like that is. Seeing her endure these obstacles is both gripping and kind of terrifying.

For a picture like this to work, we need to believe that the central character is hell-bent on achieving their goal. Annette Bening does just that, capturing Nyad’s unwavering drive. The actress isn’t afraid to make her semi-obnoxious at points. She’s a little egotistical, a little single-minded. It’s a terrific performance. Jodie Foster is even better, showing the conflicting emotions that drive Bonnie. On one hand, her goal is to help Diana meet her goal; on the other, doing so means putting her own life on the backburner. Foster brings a great deal of nuance to the role.

Nyad stumbles on occasion, notably in a series of flashbacks showing Diana as a child. They don’t work, especially since the subject of childhood sexual abuse is introduced without being sufficiently dealt with. A couple story points are also a little too condensed, causing them to feel rushed through. Phenomenal work from Bening and Foster more than carries the film, as does the revelation of the swim’s inherent perils. And when the story gets to its triumphant ending, you won’t care about those minor flaws anyway.

out of four

Nyad is rated PG-13 for thematic material involving sexual abuse, some strong language, and brief partial nudity. The running time is 2 hours and 1 minute.