Not always.
The sleep learning track is for when you are asleep. It should not be used when you are driving or using machinery. And never use it when your being distracted is a danger to yourself and others. It's not suitable for outdoors walking or exercising. At the very least you should be sitting down when listening.
You can use it while playing at the computer. I don't recommend it when you're writing an important document because it can zone you out.
Alex
