No gym membership, no problem in the Dominican Republic

Mirador del Sur, a Royal palm tree-lined park with views of the Caribbean, is normally a quiet sanctuary in this bustling capital. But every other weekday afternoon a trailer truck parks at its entrance, pulsing technobeats erupt from giant speakers, and exercise ensues – en masse.

Forget CrossFit. The most popular exercise class in this city of 1.5 million is a free hour-long group exercise session held in the middle of a closed park avenue.

What began nine years ago as a public service from the national lottery system has become a ritual for hundreds of Dominicans who brave the Caribbean heat to sweat through a calisthenics routine.

"We get 200 or more people for every class," says Ramon Rosario, who helps organize and run the classes for LEIDSA, the lottery system. The lottery is required to spend a certain percentage of its profits on public programs. "People from all classes of society and all parts of the city come. They have come to depend on it."

The draw is part economical – gym membership fees here can rival those in the US, although Americans earn more in three months than Dominicans do in a year, on average – and part fun.

"You're in this big group, so it feels like you're part of something. It goes by quickly," says Christina Baustista, a middle-aged woman who takes the class regularly in an effort to lose weight.

At 5:30 p.m., with temperatures in the high 80s on a recent Wednesday, Ms. Baustista took her spot in the class several rows from the trailer.

"Uno, dos, tres, cuatro," the instructor began from the trailer's stage, leading the class of mostly women through a high-stepping warm-up routine. One hour, 400 free bottles of water, and a series of slides, kicks, punches, and arm raises later, the music died down and the class ended with cheers.

"It's a good class for burning fat," Baustista says.

Burning fat is a priority for both Dominican women and the government here. A 2010 survey of obesity rates by The Henry J. Kaiser Family Foundation stated that nearly 2 of every 5 Dominican women ages 15 and older were obese, tied for 17th worst in the world. The US rate was 48 percent. (Only 1 in 10 Dominican men was obese, according to the figures.)

Taking note of the class's popularity, the Santo Domingo city government and insurer ARS Humano launched more free exercise sessions. That program, which began in five parks, is slated to expand to all of Santo Domingo's major public spaces next year.

It is accompanied by a plan to build outdoor "public gymnasiums." Those gyms consist of circuit training and other exercise machines bolted to the ground and available round-the-clock.

"For the people that use this, it's an important service," says Julia Diaz as she works her legs on a weight machine near the public exercise class. Exercise "should be for everyone."