It's an analogy, not an exact thing.

The difference of course, is when you lie down to sleep you go unconscious. If you know how to attend to your experience no matter how it shifts, you remain aware.

What difference does this make? Given the stage 3 sleep is one of the most restorative things we have, and that awareness during stage 3 sleep has been shown by research to be possible and also been shown to deep the restorative results, here are some of the results of such conscious attention:

1. Radical reduction in all kinds of physical pain

2. Strengthened immune, cardiovascular, central and autonomic, musculoskeletal, gastrointestinal - in short, all systems of the body.

3. Radical reductions in depression, anxiety, trauma, and dozens of other mental health challenges

4. Far easier habit change (eating, exercise, recovery from addiction, etc)

5. Improvement in all forms of physical skills, through sports, dance, music, etc

6. Improved productivity and general work performance

7. Better sex (though that would capture your attention

8. More intimate relationships

9. Greater ability to engage in both critical and creative thinking

10. Deeper sense of meaning and purpose in the universe.

And that's just a tiny fraction of the benefits.