In the Gym: Heavy Weights vs. Light Weights

Weightlifting is one of the most important things women can do for overall fitness, especially as we age.

From boosting metabolism to increasing bone density, experts say it's one part of any workout regimen that shouldn't be overlooked.

"As you age, some significant body decline can happen if you don't act to do anything about it," says trainer Ben Greenfield, the Get-Fit Guy.

"Muscle strength peaks around 25 years old, plateaus through 35 or 40 years old, and then begins to decline quickly, with 25 percent loss of peak strength by the time you’re 65."

He adds that bone density decreases as the calcium content of bones lessens, which can lead to an increased risk of osteoporosis or fractures, especially in women.

But as Greenfield says, "All of this can be slowed and even reversed with a proper weight-training program."

So when it comes to finding the proper program, are light weights or heavy weights preferable?

"For sculpting and toning, muscle exhaustion is more important than actual weight lifted — and a set of 30 light squats can do just as much good as a set of five heavy squats," says Greenfield. "However, if your goal is strength and bone density, a heavier weight trumps a lighter one."

The key to seeing results from lighter weights? Lots and lots of reps.

"I believe in lighter weights and more reps," says trainer Martha Guttuso of Flair Fitness in Darien, Conn., who adds that in order for lighter weights to be effective, "you really need to do it until your muscle is exhausted."

That point is different for everyone, and depends on what muscle group you are working, she explains. One way to tell if you've had enough? "When you reach the point when you feel like you just can't do a single more repetition," Guttuso specifies.

For Guttuso, part of the appeal of lighter weights is having the ability to engage more than one part of the body at a time. "Because it’s a lighter weight [for bicep curls], I can really be moving my lower body," she explains. "I can be activating other things."

Guttuso adds that it doesn't take heavy weights to see a difference in your body. "I truly believe in resistance training with your own body weight," she says, and doing moves including "push-ups, planks, leg raises and squats" can get results.

But whether you're using light or heavy weights, always practice your weight training regimen safely and responsibly. To avoid risk of injury, make sure to learn how to properly move weights under the guidance of a personal trainer, advises Greenfield.