Toddler sleeping problems

Dylan has not been sleeping well on and off for about two weeks. Some nights he is waking up between 3 and 5 in the morning and not always going back to sleep. Is it possible that he isn't getting enough exercise during the day to make him sleep through the night? He only has a 1 hour nap normally. I do not know what could be going on. Any ideas?

Moms Expertise
    Thank you everyone for the comments! Dylan does go outside quite often and for pretty long periods of time. He loves being outside. There have been a few days where he couldn't go out due to weather and he definitely didn't get a lot of exercise those days. His bedtime is already a little late in my mind. I lay him down at 9:00 or 9:30. I don't work outside of the house right now so there is no need for him to be getting up real early. His normal time to wake up in morning is like 8:00am. There isn't a lot of noise here at night.
    About Melissa
    Born: Center Line, Michigan
    Current: New Baltimore, Michigan
    Birth: March 16
    On since: Apr 28, 2014