When we first moved into our two-bedroom apartment in Manhattan, my roommate—a friend from my CrossFit box and fellow fitness-junkie—and I (half) joked that we should get bunk beds and turn one of the bedrooms into a home gym. Beyond being superb material for a pick-up line at CrossFit competitions, it’d give me a place to store all my exercise equipment. And boy oh boy did I have a lot of equipment: kettlebells, exercise sliders, dumbbells, a wall ball, a yoga mat, yoga blocks, a Theragun, and yes, even a barbell (and plates!).

You’re probably wondering why I had so much damn exercise equipment. For one, I used to work part-time at a CrossFit box in Manhattan that closed down—which meant I got a lot of equipment at a huge discount (I love a good bargain). But the main reason is that as a health and fitness journalist, trying and reviewing new exercise gadgets, fitness gear, equipment, and even studios is part of my job (one time I even tried a Naked Yoga class).

My roommate and I ultimately opted out of bunk beds (her boyfriend at the time wasn't thrilled by the idea)—which meant that I had to squeeze my fitness equipment into the same room as my bed, work-from-home set-up, and dresser.

And when I set about Marie Kondo-ing my home gym, I realized there’s only one piece of equipment I’d wax poetic about: my weight vest.

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What is a weight vest exactly?

It’s pretty much exactly what it sounds like: “It's a vest that usually weighs anywhere from 10 to 45 pounds that you wear while training to add resistance and make whatever exercise you’re doing more difficult,” explains physical therapist and certified strength and conditioning specialist (CSCS) Lauren Lobert, owner of APEX Physical Therapy.

Think of it like an ankle weight or weighted arm band—for your trunk. The difference, according to physical therapist Hannah Dove, CSCS at Providence Saint John’s Health Center’s Performance Therapy, is that an ankle weight makes exercise harder on your legs, while a weight vest makes most exercises harder on all muscles. “Unlike a dumbbell or kettlebell, you don’t have to worry about holding onto a bulky weight while exercising and taxing just your arms because the weight is safely secured onto you,” she says.

Weight vests go on over your normal workout attire, secure to your body with Velcro, and look something like combat gear. In fact, while my vest is black, most are army green or camo print. But don’t get it twisted: Weight vests meant for exercise are not bulletproof. (Although 5.11 Tactical, the manufacturer of my weight vest, also carries mission-specific equipment for folks in uniform).

While they're slightly larger than a vest you’d wear for laser tag, they’re way smaller than those lead aprons you wear for an X-ray at the dentist. And as long as you secure the straps tightly before you start training, weight vests shouldn't jostle or jiggle around.

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Why I love my weight vest so much

The reason is pretty simple: It’s versatile AF. I can wear it inside or outside, at the gym or in my room, during any bodyweight movement like lunges, step-ups, air squats, push-ups, pull-ups, sumo squats, or sit-ups—and even during cardio sessions spent running, rowing, or jumping rope to make them harder.

“For most people, these vests will add about 5 to 10% of your bodyweight onto yourself, which increases the demands on your muscles and cardiovascular system and makes any exercise more difficult,” says Dove. Translation: It helps get you fitter, faster.

“It’s crazy how much harder exercises become with the increased load,” says CrossFit Games athlete and certified personal trainer Kari Pearce, who uses a weight vest in training. "You will feel the burn in your glutes, quads, and hamstrings, so much more quickly."

In fact, research has shown that training with a weight vest can improve both endurance and strength performance, depending on your goals and how you wear it. For a cardio-focused weight vest workout, Pearce suggests doing burpees. “In general, burpees are my favorite go-to exercise because you can do them anywhere. Add a vest and your heart will starting racing after just a couple of reps.”

When I only have five minutes to get a workout in, I throw on my vest and see how many burpees I can do in that time. When I have more time, I like to do CrossFit workout Cindy (as many rounds as possible in 20 minutes of: 5 pull-ups, 10 push-ups, 15 air squats) in my weight vest after running three miles. When it's too cold to run outside, I like to do step-ups, burpees, and jump squats in my vest. Like I said: versatile.

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Should you try a weight vest?

First, ask yourself: Can I complete un-weighted bodyweight movements like the air squat, lunge, or push-up with good form? If the answer is no, Dove says that adding a weight vest could increase the risk of injury to your joints. (If you already have chronic knee or lower-back pain, Lobert suggests opting out of weight vests completely, as they can "cause issues to people with low back, hip, or knee degeneration issues.”)

But if the answer is yes, Dove says, “weight vests can be a great addition to your home gym, especially if you’re looking for an easy way to make bodyweight movements more intense and don’t have space for a dumbbell rack." (If you do buy one, start by wearing it around three days a week while you work out.)

Prices vary depending on the brand of weight vest and how heavy they are. The RUNFast/Max Pro Weighted Vest starts at 12 pounds and $31 (amazon.com). The ZFOsports Weighted Vest starts at 20 pounds and $39 (amazon.com). Others, like many of the models from 5.11 Tactical, will run you closer to $200.

Ultimately, whether you’ll love your weight vest as much as I love mine comes down to your personal fitness goals and tastes. For me, it’s the perfect space-saving piece of equipment that helps me get in a solid workout whether I’m wearing it while running through Central Park—or in my closet-sized bedroom.

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