My friend has one of these

http://www.competitiveedgeproducts.c...11&affiliate=4

in her living room and she exercises on it while she watches tv. (Not this exact one, but it's a similar device)

I just read an article that says you can use it while you're checking your email, etc. I would assume that means sitting down? Would I be able to use this during working hours? I know it wouldn't have the same effects as doing it while standing, but would it have any effect at all? Would it harm my knees? Other joints? I just want to know if it's too good to be true.

I have a mini stepper. You definitely have to be standing to use one.

That is what I thought but who checks email standing up?

This is the Dr they cited in the article

http://www.mayoclinic.org/news2005-rst/2630.html

http://ndc.mayo.edu/mayo/research/levine_lab/

Also here is another device.

http://www.betterhealthinnovations.c...p/df-sd030.htm

This one specifically states it can be used while sitting, but my question is still am I going to injure myself?