(At) Work Your Core

Try these exercises at work to keep your core firm.
Chair Squat
You can do this pretty much any time that you are working at your desk, but probably not for long, as it should tire you out quickly! Take a seat in your office chair and position your feet in a way that you feel you could stand up from your desk without using your arms to help, with feet shoulder-width apart or a little beyond if you are having trouble finding that sweet spot. Keeping your abs engaged (like you are bracing for a punch in the stomach), bring your butt up off your seat and hover an inch or two above your seat. Try holding this as long as you can while still being able to lower yourself back down into your seat in a controlled fashion; don’t let your abs go and just slam back down!
Knee Lifts/Alternating
Sitting in your chair, simply lift your feet an inch off of the ground and hold it as long as you can. You should feel this in your lower abdominals and hip area. Use your forearms to brace yourself on
the arms of your chair or your desk. For added difficulty, alternate lifting your knees up even more while never letting the bottoms of your feet touch the ground.
Plank
This one can be a little trickier to discreetly pull off at work. But if you ever find yourself standing and bending over your desk at work, why not pull your feet back away from your desk, straighten your spine, and engage those core muscles while you look at blueprints, diagrams, etc.? Make sure your desk is sturdy enough to support your weight!
Trunk Rotations
This is a simple movement, but doing it deliberately is the key to activating our muscles and getting results. While focusing on keeping your legs and hips solidly in place, use your abdominal muscles to turn your shoulders. If you are doing it right, you should quickly feel your abdominal muscles working; if it doesn’t seem difficult, make sure you’re not turning your lower body to aid the movement.