Would your employer prevent you from going outside for 5 minutes every hour?

That actually sounds like a great idea. Once an hour, head down to the street and walk a couple blocks.

I'm sure they wouldn't mind - the timing would obviously be dependent upon business but that isn't a consideration for the smokers I work with, they just leave their colleagues to take up the slack.

I run AntiRSI and take a 5 minute break every hour. Never had an employer complain about me not staying chained to my desk for 8 hours.