THE BEACH AT Maryland’s Sandy Point State Park isn’t usually packed with a crowd in skimpy bikinis and swim trunks when it’s 37 degrees outside. But the scantily clad masses braving the frosty air Jan. 24 were just warming up — for a dip in the even chillier Chesapeake Bay.

Welcome to Plungapalooza, a fundraiser for the Special Olympics of Maryland and the country’s biggest polar bear plunge event. Determined to challenge themselves, support a worthy charity and stave off some winter blues in the process, close to 12,000 people raised a minimum of $50 each for the privilege of spending at least a few seconds in frigid water.

So, what does it feel like to go swimming in the 33-degree water? “Cold,” says Aaron Foster, part of a group of D.C. firefighters that have made the swim an annual adventure. (As have many others from the area. Last week’s plunge was the 13th, and every year it’s grown exponentially — there were 350 participants in 1997 and 7,400 in 2007.)

He elaborates: “Your body locks up automatically. First it hurts, then it goes numb, then it thaws and then it hurts again.”

As tempting as that sounds, he and his pals say it’s worth the discomfort. Really.

“Maybe it’s bragging rights, something you can say you did,” says B.J. Duty, another firefighter. “Plus, it’s for a great cause, and it makes you feel good when you do it.”

He’d be preaching to the choir in Finland, where winter swimming is a beloved institution thought to invigorate the body.

“Oh, it’s quite healthy. Blood circulates better, and it helps with arthritis,” is the official word from a spokesperson at the Finnish Embassy in Washington. Finns also think it lowers blood pressure, strengthens the immune system and boosts longevity.

But David Pearle, a cardiologist at Georgetown University Hospital, isn’t having any of it. “There’s no medical evidence [of health benefits] at all,” he says, adding that these events could pose a threat to participants’ well-being. “Cold water makes your blood vessels constrict and your blood pressure goes up, so there’s a potential risk for someone with underlying heart disease.”

Plungapalooza’s organizers aren’t too worried. In the 13 years they’ve held the event, no heart attacks have been reported. But just in case, divers wearing dry suits stand in the water at the ready, and doctors watch from land.

Whether or not a plunge is a wise move for one’s body, Plungapalooza’s head honcho, Tom Schniedwind, is convinced it’s good for the soul.

“Psychologically, this event occurs during the darkest days of winter — the time when bills come due from Christmas, and the weekend between conference championships and the Super Bowl,” says Schiedwind. “Area football teams usually aren’t doing well, and folks need a pickup.”

It’s certainly a shock to the system — but it’s more than just a fleeting moment of daring. The event is a winter carnival, lined with food stalls and dotted with folks in crazy costumes. And hordes of 20- and 30-somethings, many affiliated with local police and fire departments, spend the morning before the plunge tailgating in the parking lots surrounding the beach.

No one seems to train for the event per se, but a fair number prep themselves with some alcohol. And after they’ve had their fill of teeth-shattering cold, they come dashing back onto land and head straight to the changing tents to snuggle in sweatshirts, pants and blankets.

After she was fully dressed and recuperating, Suzannna Strasburg, the fiancee of another firefighter, summed up the experience of jumping in for the first time: “I have never experienced pain in my feet like that before — but everybody had a smile on their face. It was very fun, very exhilarating.”

Maybe she’ll back next year. You can already save the date for next year’s plunge: Jan. 30.

Written by Express contributor Amanda Abrams
Photo by Daniel Barry/Getty Images