Take a 5 min time out.
After every hour of work, give yourself a five-minute time out to change your posture and reset your focus.
If you were standing, find a chair and sit and vice versa for sitting.
This helps to connect with your senses in the present moment.
Use that time to pay attention to what you see, hear, touch and feel, etc. It is a quick way to bring a little mindfulness into your day.