# Sandbox.PhysicsBody.Sleeping

```csharp
bool Sleeping { get; set; }
```

Physics bodies automatically go to sleep after a certain amount of time of inactivity to save on performance.
You can use this to wake the body up, or prematurely send it to sleep.

Declared in [Sandbox.PhysicsBody](/api/Sandbox.PhysicsBody).
Assembly: `Sandbox.Engine`.