When most people think of indoor cardio exercises, they immediately think about walking, jogging, or running on a treadmill. But hang on, treadmills aren't the only choice! In fact, you can still get a killer cardio workout without ever stepping on a treadmill. Below, we've got eight amazing indoor cardio exercises you can do even if you never owned or used a treadmill in your life.

Jump Rope

Jumping rope is an amazing form of exercise, thanks to the fact that you are repeatedly jumping. Jumping requires far more muscular energy than running, jogging, or walking, and it puts a pretty noticeable strain on your cardiovascular system. You'll be breathing hard in just a few minutes of jumping rope, and you'll feel the burn in your legs. If you really want to kick the intensity up a notch, throw in a few "double unders." The high-intensity workout will have you breathing hard in no time.

Box Jumps

Once again, you can harness the power of your jumping muscles to give yourself a killer cardio workout. Set up a box or just jump up onto a ledge, set at knee height, thigh height, or even waist height. The explosive action of jumping will use up a lot of anaerobic and aerobic exercise, giving you a cardio workout that you'll feel within seconds.

Jump Squats

Mix a bit of cardio into your lower body workout by adding a jump at the end of your squat. The squat portion will engage your muscles and burn ATP energy, then the jumping portion will work your cardiovascular system and burn fat. A few sets of these will have you sweating hard and breathing heavy.

Switch Lunges

This one isn't as hard on your cardiovascular system, so it's a bit easier for those who are just getting used to mixing resistance training with cardio. The fact that you're jumping between movements means you'll use up a lot more energy than you would simply lunging. The effects on your heart and lungs are amazing!

Plank Jacks

You can mix this workout into your routine to shred your core, shoulders, arms, and upper body while getting a killer cardio session. The fact that you're in plank position the whole time means you'll feel the burn in your muscles, and the constant movement of your legs will get your cardiovascular system working like a boss.

Mountain Climbers

This exercise is easy enough, but it's great for shredding your core and getting your heart burning. After a few dozen of these, you'll be breathing hard and feeling the burn in your upper body, core, and hip muscles.

Burpees

Burpees are the ultimate cardiovascular workout for resistance trainees! The fact that you squat, jump back, push-up, jump forward, stand, and jump into the air means your body is always moving, and there's no time for rest. It's a killer cardio exercise that will push you to your limits, no matter how often you do them.

Stairs

Sometimes, it's best just to keep it simple! This is a particularly useful exercise to do in your office building, where you have more than three flights of stairs to climb. Both the ascent and descent will work your muscles and cardiovascular system, so it's worth spending time walking, jogging, or running up and down those stairs.

A few simple exercises, but they can have an amazing effect on your cardiovascular conditioning! Best of all, you'll never need a treadmill to do them.

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