You already know this, but sitting all day long is seriously not good for you. Sedentary behavior is correlated to poor health and can increase your risk of developing everything from heart disease to diabetes and even cancer. As badly as we might want to avoid these outcomes, the reality is that a lot of us simply don't have the time or ability to spend all day on our feet.

The good news is it's possible to break up all that sitting with small bouts of exercise -- even if you don't have access to an office gym or your only option for exercise at your desk. While these moves shouldn't replace a more vigorous workout routine, they can complement one. By regularly practicing this office workout, you'll avoid turning into an immobile lump during the workday.

Stair climbing:

Assuming you have access to a staircase at your job, here's a simple way to squeeze some cardio into your workday: Set a timer for as many minutes as you have (whether it's two, five, or 10, it'll still be good for you) and take to the stairs.

Pushups:

If you have access to a desk or the floor, then you have access to a powerful workout for your pecs, triceps, deltoids, and more. If you already have the muscle mass to do regular pushups on the floor (and you have an office door you can close or co-workers who won't be freaked out by some in-cubicle exercise), then by all means do so.

The "magic carpet ride":

You don't even need to leave your chair for this move. While sitting on your chair, cross your legs so your feet rest under your ankles. Next, put your hands on the chair's armrests, engage your core, and lift the rest of your body a few inches off the chair. Hold the pose for 10 to 20 seconds, rest, and then repeat for a total of five times.

Planks and side planks:

Core training is easily one of the best ways to build full-body strength and functional fitness. And some of the best moves for developing core strength require no equipment beyond your own body -- so you can do them in the office or anywhere else.

Wall sits:

Boost your strength and endurance with this simple yet challenging move. Stand with your back against the wall, then slide your back down the wall while bending your knees. Stop when your thighs are parallel to the floor and hold for 30 to 60 seconds.

Chair dips:

When the military commend a strength-boosting exercise, you know it must be effective. Sit on your desk chair, put your hands on the edge of the chair (by your thighs), and scoot your butt forward until it's just off the chair. Then bend your arms and lower yourself to approximately six inches below the seat. Straighten your arm to rise back up. Repeat this motion 10 times.

Calf raises:

This is a simple but effective calf toner. Stand near your desk or the wall so you can place your hand on that surface for balance if necessary. Raise your heels off the floor as high as possible, and then slowly lower them back down to the floor. Repeat this 15 times. If you want to increase the challenge, hold something heavy in your hands while performing the move.

Squats:

They're the exercise that everybody loves to hate, but they're also incredibly effective for building lower body strength. Proper form is critical here if you want to protect your knees, so make sure you know how to squat before performing this exercise. Once you're confident about your form, go ahead and incorporate this move into your routine. Aim for sets of 10 squats.