Instructor Leo Wright’s “Knockout Bride” class at New York Health & Racquet Club is allotted 45 minutes, but the kickboxing hybrid course usually runs much longer, sometimes stretching to nearly three hours. Who would be so committed to sculpting their physique as to come back week after week for such a protracted workout? The name of the class suggests the answer.

Brides-to-be have always wanted to look their best walking down the aisle. These days, they are going so far as to incorporate their fitness and weight loss goals into their wedding planning and budgets. Many hire personal trainers who specialize in getting clients wedding-dress ready, while others opt to purchase the bridal packages offered at a growing number of city gyms and exercise studios.

“The flowers, the food — that’s all secondary,” a 26-year-old accountant who is planning an August wedding, Jannie Leung, said. “My biggest fear is how I’m going to look that day. That’s what I have nightmares about, real nightmares about my dress not fitting.”

Those dreams, along with some noticeable results — she says her stress level and her dress size are down — have made Ms. Leung a “Knockout Bride” regular. The class is part of the club’s Bridal Checklist program, inaugurated last year.

Depending on the client’s goals and budget, the program can include consultations with a nutritionist and ballroom dancing lessons. The exercise studio Physique 57, with locations in Manhattan and Bridgehampton, offers a five-week Bridal Countdown. The package includes 15 of its prop-filled strengthening and stretching classes, as well as a consultation with a local wedding planner, a free makeup application, and guest passes for the bridesmaids.

Beneficial Fitness in Murray Hill has a Buff Brides personal training package. The regimen shares its name with a FitTV reality show on which the gym’s owner, Julian Walker, appeared.

“Brides are a different breed of client,” Mr. Walker said. “They come in very motivated to get results, and they have a deadline.”

As engagements get longer — they average 16 months, according to Brides magazine — and weddings more extravagant, it’s little wonder that brides feel the need to “measure up,” the author of “One Perfect Day: The Selling of the American Wedding” (Penguin), Rebecca Mead, said. “The fitness business has plenty of time to make its pitch: ‘Get yourself in shape for the most important day of your life; get yourself in shape for the most documented day of your life,'” Ms. Mead, a staff writer for the New Yorker, said.

For marketing executive Sharese Bullock, who is trying to lose 35 pounds before her July 2009 wedding, all the hours clocked at the gym are about long-term wellness — not a single day. “The wedding date gives you a finite goal, but it’s more about thinking of a lifetime of healthy living,” the 28-year-old Brooklyn resident, who is enrolled in the Bridal Checklist program, said.

Some fiancées are shorter-sighted. Of the 1,000 brides-to-be surveyed for an article published in the June issue of Fitness magazine, 36% said they would take weight-loss pills or appetite suppressants if it meant reaching their ideal wedding weight, while 29% said they would be willing to move in with their future mother-in-law for the same reason. While just 6% admitted they would go under the knife, about a quarter of the respondents said they would forgo wedding gifts or their honeymoon — or would be willing to gain a post-“I do” 25 pounds — if they could walk down the aisle several pounds lighter; one in five women said they would postpone their nuptials if they hadn’t met their fitness goals in time.

“The extremes we saw were a little concerning,” the editor of Fitness, Denise Brodey, said. “People put so much emphasis on this one special day. It’s one of those times when women just combust. They say, ‘Okay, I’ll do anything to look good in my dress.'”

Where are the grooms-to-be in this equation? Certainly the tuxedo leaves less to answer for than a strapless bridal gown. “We’ve found that the average man doesn’t care if he’s carrying a little too much weight on his wedding day, but some will make the effort,” the founder of the online men’s magazine groomgroove.com, Michael Arnot, said. “If there’s one time to get in shape, this is it.”

gbirkner@nysun.com

Bridal Checklist at New York Health & Racquet Club, 800-472-2378, nyhrc.com, prices vary; Bridal Countdown at Physique 57, 212-399-0570, physique57.com, $33 a class, discounts on multi-session packages; Buff Brides at Beneficial Fitness, 212-532-1383, beneficialfitness.com, $95-$135 an hour.