Take in lots of water.
Think of this. When you drink water, your body expels it after getting the nutrients. As such, taking more water gives the chance to urinate. Use this fact to your advantage and drink lots of water at the office. This will prompt you to use more time walking to take a leak. This works best if you choose a work station that is farthest from the bathroom. You can also sink some more exercises as you move from the bathroom back to your desk.