My female dog Mimi

Question
My female rescue dog Mimi, has been fixed but she has been acting a little different lately.  She is an inside dog and is very spoiled by the whole family.  Lately, she wants to be outside constantly (she's part Maltese and Shiatsu) lately, and is constantly pacing..like she is wanting to get out and run wild.  Even though she is fixed I was wondering if she still get's the feeling of wanting to mate, could that explain her behavior?  

Answer
Well sometimes it's a lack of exercise,even small need to go out for long walks and allot of play time-allot of times when dogs don't get enough of that from you,they try to get it themselves by pacing ect

Try to set aside at least one hour a day for play time and see if that helps