# Sandbox.PhysicsGroup.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.PhysicsGroup](/api/Sandbox.PhysicsGroup).
Assembly: `Sandbox.Engine`.