Tracy Doherty teaches people of all ages how to swim at the Rex Wellness Center in Wakefield.

She finds her adult students are much like the very young ones.

“Most of my clients have no swimming experience or their parents just didn't do it for them when they were younger,” Doherty said.

She says all 10 members of her current class were afraid to even put their face in the water. And for African Americans, the problem is magnified.

“African Americans – 70 percent of us don't know how to swim,” said Manny Marbet, a 63-year-old swim student.

Marbet and his wife, Iris, decided to improve that statistic by two. She started the class to help her recover from knee replacement surgery.

“And my knees feel much better and I lost 24 pounds and went down 4 dress sizes in the process,” Iris Marbet said.

Because of the more weightless environment, swimming is great medicine for ailing joints.

“Even if you're walking through the water, it's 80/20 percent - you're only walking 20 percent of your own body weight,” Doherty said.

Kathleen Downs, a 69-year-old swim student, said, “my hip on my left side, which has to be redone, it hasn't hurt me lately at all.”

Downs only wishes she'd learned to swim sooner.

“I'm more mentally alert,” she said. “I have a lot more energy and my attitude is much more pleasant.”

Even her cholesterol and blood pressure numbers have improved.

It's something she - and the other students - don't plan on stopping.

“Swimming is for life and it's for fitness and anybody can do it,” Doherty said.