In the fitness class Jessie Syfko created for a nationwide gym chain, exercisers wear weighted vests that add a challenge to their workouts.

"We add weighted vest as a micro load, right, so their vests are anywhere between five and 12 pounds, depending on which vest you use," said Syfko, the creator of the class at Life Time gyms.

Weighted vests are increasingly showing up in fitness classes and on jogging tracks, touted by social media influencers as a way to keep bones healthy, improve performance and even accelerate weight loss. They are exactly what they sound like – vests that add resistance to the torso through pockets with removable weights.

But experts say there’s a lack of robust research on their benefits, so it’s unclear how much of the hype surrounding them is justified.

When you think about how exercise works, the idea that a weighted vest will help you meet fitness goals like weight loss, muscle growth or preventing bone loss might make sense on the surface. Adding weight to the vest adds resistance to your everyday activities without changing up your patterns.

The vests may, in fact, offer benefits for healthy adults, experts say – although no one should expect transformative or instant results.

"If this is a way for you to kind of incorporate some of these activities, like resistance training-ish, I think it's great," said Kristen Beavers, associate professor in the department of health and exercise science at Wake Forest University.

One 2020 study from Wake Forest University School of Medicine in North Carolina found that adults between 60 and 85 years old who wore weighted vests at times during the day when they were most active lost about the same amount of weight as those who didn’t wear them. They also lost the same amount of bone density, which happens as we age but can be slowed by building muscle.

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