Cats are nocturnal creatures. In the wild, hunting is often done during nighttime; even with domestication, pet cats tend to keep this inclination to be active at night. 

The behavior is often distinct in pet cats that lack physical and mental activity during daytime, especially when the owner is out of the house most of the day. For lack of something to do, a kitty usually spends most the day napping. 
Pet cats that have developed sleep patterns similar to humans have been shown to still wake several times during nighttime, and shifts into play mode. 

Simply locking your kitty out of the bedroom will not always be an effective strategy. A persistent cat will vocalize loudly and scratch at the bedroom door to be let in. You best bet is to increase your pet’s activity level during the day to exhaust his energy and keep him sound asleep at night. 

Any changes in your pet’s behavior or routine should prompt a consultation with your Newmarket animal clinic.  Visit this link for more information.