Here’s why your dog shivers after waking up 👇 1. Cold / Temperature Regulation One of the most common reasons: your dog’s body might be cold when they wake up. Just like humans, dogs shiver to generate heat when their body feels chilly. 2. Muscle Fatigue or “Reset” After Sleep Sometimes trembling right after waking can simply be due to muscle stiffness or fatigue. After lying down for many hours, muscles may feel “stiff,” and a small tremble helps the body reset. 3. Pain or Discomfort Shivering