Buying a weighted vest was one of the best fitness investments of my life - it made me faster and stronger in 4 weeks

• I tried different workouts like running, calisthenics, and HIIT in a weighted vest for a month.
• I noticed major fitness improvements, especially to my endurance and core strength.
• I'd recommend it for experienced athletes, but make sure you get the fit just right for best results.

It's not an exaggeration to say buying a weighted vest has been one of the best fitness investments of my life, no pun intended.

I'd been eyeing weighted vests for months, and researched different styles and prices, and finally jumped on the opportunity when my top pick from Rogue Fitness went on sale.

The vest is modeled after military-style armor plate carriers. The plates come separately, and are sold in pairs, from five pounds each up to 20 pounds. I opted to wear 14 pounds worth of plates.

I wore it with three different styles of workout: running, standard body weight movements like squats, pull-ups, and push-ups, and HIIT circuits.

After working out with it for more than a month, I've noticed big improvements to my speed, endurance, and core strength, without making any other changes to my routine.

It's not for beginners

First, I wouldn't recommend investing in a weighted vest unless you're already fairly fit.

If you're daunted by the thought of running a few miles and doing dozens of burpees, push-ups, and pull-ups in a single workout, a weighted vest will likely be too challenging to use consistently, or you may need a lighter model.

My speed and cardio endurance noticeably improved

Fourteen pounds may not sound like much, but it quickly takes a toll on your whole body.

Running at my usual pace, I found myself breathing much harder than usual. Exercises that I don't normally consider to be cardio, like squats and push-ups, got my heart racing, too.

That meant I had a lot of options for workouts specifically designed to push my cardio capacity to the max, with lots of jumping squats and lunges (like this one from personal trainer Jay T. Maryniak, whose Instragram workouts are great).

As a result, I became significantly better at maintaining explosive power or keeping a good pace even when I was tired.

Even better, I noticed my running pace improved when I took off the vest. Without consciously trying to increase my pace, I shaved about 30 seconds off my casual mile time after a few weeks of using the vest regularly.

My core and shoulders got an extra workout every time I wore it

While I had done research into vests prior to buying one, one of the biggest benefits wasn't in any of the reviews I read.

No matter what you do while wearing it, the vest activates your core, shoulders, and back muscles. This makes it an amazing way to turn even simple exercises into a full body workout.

With the weighted vest, I could focus on bigger muscle groups, while still getting the benefits of a rock-solid core.

It can be hard to wear for certain movements

Despite everything I love about my weighted vest, my one complaint is that it doesn't fit quite as snugly as I'd like. I'm a small person (5'2") and the vest hangs rather loosely around my waist and shoulders, even with my best efforts to adjust it. As a result, it tends to bounce and jostle when I'm moving around.

For most exercises, this is easy to solve by simply holding on to the vest with one or both hands to stabilize it.

Burpees in particular were a challenge, since the back plate hitched up when I jumped from a plank into a squat, hitting the back of my head if I wasn't careful.

If you're also a smaller person, read the specs carefully to get a vest that works well for you.