In an exercise room at the Lakewood Ranch Branch YMCA, Ruth Dickmann is holding her fingers on her pulse and counting her heartbeat. She is five months pregnant and just finished an exercise set.
The "Toning for Two" class for pregnant women has stopped to take a break to check pulse rates after brisk moves of low-impact aerobics.
Dickmann's heart rate is 120 beats a minute, well below the threshold that exercise instructor Ute Stern-Ratzel has set for the class.
"When the mom exercises, the baby exercises. The baby's heart rate actually goes up and they are more or less in exercise mode," said Stern-Ratzel.
"It takes a little longer for the heart rate to go down in the baby than in the mom," she said. "That's why we do take breaks to make sure that the heart rate won't go up too high for either baby or mom."
Stern-Ratzel is a physical therapist who started teaching "Toning for Two" at the Y last month. She taught a similar class at a hospital in New York before moving to Florida.
The purpose of "Toning for Two" is to encourage fitness in preparation for labor and delivery, and teach women how to prevent that bane of pregnancy, backache.
Part of why Dickmann joined the class was because of her mother's experience. Dickmann is expecting her first child, a baby girl, in September.
"My mom walked every day during one of her pregnancies and said that really helped her during labor," said Dickmann.
"She said it was like night and day between the one pregnancy when she exercised and the other one when she didn't."
At one time, doctors didn't allow women to exercise at all because of the belief that pregnancy was already too much of a change and challenge.
Those days are long past. According to the American College of Obstetricians and Gynecologists, even women who ran before pregnancy can keep running after they become pregnant.
Exercise doesn't have to be tough to make a difference, says the obstetricians group. A daily half-hour of exercise like walking or swimming is enough to help increase energy, improve mood and reduce problems like bloating and swelling.
Importantly, it can help prevent or treat gestational diabetes.
Stern-Ratzel wants to also teach pregnant women about posture and to be aware of how they are standing.
"Body mechanics are very important during pregnancy," she said. "We work on posture every time we do the exercises."
The classic pose of pregnancy, protruding belly forward, lower back arched to compensate can result in an achy back. The stance is also what makes women waddle at the end of their pregnancies.
It's a natural reaction because of the weight of the baby, but not so good for the back, said Stern-Ratzel.
Another contributor to poor posture is the hormone relaxin that is released during pregnancy. Relaxin loosens joints, making them less supportive.
To move the center of gravity into normal and take pressure off the back, women need to shift the pelvic bones and tuck in the belly. Doing that consistently takes awareness and practice.
"A lot of people have not paid attention to it. They just say, 'Oh well, I'm pregnant and that's why I have a backache' and 'Oh well, I'm pregnant and that's why I walk this way,' " said Stern-Ratzel.
Before women can join the class, they must get approval from their doctors. They also have to wait until the end of their first trimester.
At each session, Stern-Ratzel starts by checking every woman's blood pressure and heart rate. She ends the class with guided relaxation, telling the women to remember the feeling of being relaxed when they are in labor.
"Toning for Two" also is meant to be social time for pregnant women where they can create a bond and share their experiences.
The Y is planning a "graduation wall" with photos of moms and their infants after childbirth. The graduates and any other new mothers might want to join another new class at the Y -- "Mama Moves" -- where moms exercise with their babies.
Susan Hemmingway, Herald health correspondent, can be reached at email@example.com.
IF YOU GO
What: "Toning for Two"
When: 4-5 p.m. Tuesdays and Fridays
Where: Lakewood Ranch Branch YMCA, 5100 Lakewood Ranch Blvd.
Cost: $55 a month for YMCA members and $65 a month for nonmembers.