Dogs need to sleep at night, and they need about 15 hours of sleep a day. Puppies need about 22 hours of sleep a day. However, dogs sleep in two categories: deep sleep and light sleep. When they are in deep sleep, they are really asleep. When they are in light sleep, they just squint and close their eyes to relax, which can easily wake them up. Therefore, it is best not to disturb your dog when he is sleeping. Let the dog get enough rest.