San Diego housewife Sheila Rubin’s (Rose Byrne) life teems with shoulds. She should be supportive of her failed-academic husband, Danny (Rory Scovel), even though she no longer believes in him at all. She should eat “clean, healthy foods” and go to ballet class while her daughter’s at day care, even though all she can bear to do after drop-off is check into a motel, binge on fast food and throw it back up. She should stick to her self-professed values of peace and love — the youthful ideals that once drew her to her former antiwar-protester spouse — but it’s 1981, and all she can hear are the siren calls of the Reagan years’ most iconic forces: aerobics and capitalism.

“Physical” (Apple TV Plus) makes a maze out of these shoulds: a labyrinth of ideological contradictions that have made Sheila an Olympic-level self-loather. She judges any woman for being heavier than she is — that’s practically all of them — then judges herself for being so superficial. She pretends she’s someone else when she’s around her self-involved husband, then gets angry at him for not knowing her better. She twists any and every random comment into an insult against her, her narcissism too overripe to yield any of vanity’s pleasures.

As delicately layered as phyllo dough (a carb-y metaphor she’d hate), Sheila is an actress’s dream role, and Byrne is magnificent as this nightmarish woman we can’t help rooting for despite her awfulness. In its unvarnished portrayal of an eating disorder and especially its bleak illustration of the monomania that drives Sheila’s (embodied by an incessant voice-over that feels all the more real for its unforgiving spite and grating repetition), a series like “Physical” feels overdue in its explorations of the mental and bodily discipline that millions of girls and women feel compelled to impose on themselves. (There’ll undoubtedly be a larger conversation about the show’s depiction of eating disorders and, in this representation of bulimia, the possible suggestion that, no matter Sheila’s psychological tortures, it “works” in maintaining thinness.)

Striving for a sense of control in a changing world has long been a staple in prestige TV, so it’s in some respects surprising that the genre has taken this long to tackle the taboo issue. But while Tony Soprano longed for the “good old days” of the mob and Don Draper clung to the last years of an open WASP oligarchy, Sheila looks to the future that’s being built right in front of her eyes. When her husband is kicked out of his professor job, she’s duty bound to encourage his bid for local office and his pro-environment, anti-development platform. But even as she’s guiding his campaign (for no credit) and fundraising on his behalf, her mind’s a million miles away: onstage, in a spangly leotard, leading an army of similarly big-haired, gracefully toned women to her happy place.

Then reality hits. She first needs to learn all she can about aerobics from Bunny (a frustratingly underutilized Della Saba), the creative but financially struggling owner of a studio at the mall, where she furtively lives with her part-time pornographer, full-time surfer boyfriend Tyler (a soulful Lou Taylor Pucci). Sheila also needs to contend, at least somewhat, with the fact that exercise and body issues affect women differently, like plus-size Greta (Deirdre Friel), a fellow mom at the day care who’s revealed to be the wife of Danny’s biggest donor (Ian Gomez). Needy, friendless and convinced her husband’s cheating on her at least partially because of her weight, Greta forces the misanthropic, walled-off Sheila into the fitness-instructor role she’s least suited for: emotional caretaker.

But “Physical” is, for better or for worse, built around Sheila and Danny’s marriage, a union between two egomaniacs whose fraying bond to each other is increasingly tenuous, but just enough to sustain a final bitter chapter. The 10-part season steadily doles out their reasons for having stayed together this long, most of which revolve around nostalgic memories of their rebellion against her country-club parents. But if there’s a born cheater, Danny is one, his hunger for admiration unsated by a wife who knows him too well. And after seemingly sitting out feminism’s Second Wave, Sheila is ready to more than make up for it by trading in her “problem that has no name” for world domination, one videotape sale at a time.

There’s a lot here — I haven’t even gotten to Sheila’s mutual attraction to developer John Breem (Paul Sparks), the religious moneybags behind Danny’s opponent. “Physical” flirts with messiness at times (and has to occasionally rely on coincidences to make things fit together), but it’s built on an intriguing and idiosyncratic overlap of fiefdoms and credos.

The show’s smartest decision, other than Byrne’s casting, may be its tendency to evoke rather than spoon-feed. The reasons for Sheila’s love for aerobics, for instance, are never spelled out, and it may well be that she herself doesn’t understand the fullness of its power over her. The dance studio seems to be the one place where she doesn’t hate her body, where she can eschew her ‘70s-hangover clothes for an ‘80s girly glamour, where she feels like she’s going somewhere instead of treading water.

As with the recently released antiheroic prequel “Cruella” — whose director, Craig Gillespie, helmed the pilot — self-actualization means letting oneself embrace one’s darker impulses. It might leave you a little queasy, but there’s no denying it’s deliciously sour.

“Physical” begins streaming Friday with Episodes 1-3 on Apple TV Plus. New episodes stream weekly.

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