Is my Exercise Enough for good Sleep?

I've been reading articles that talk about how Exercise is important to create good sleep.
I do maybe 20 to 30 minutes a day, you know the basic jumping jacks, and calesthenics. Then i usually go out and walk to where i need to go.
Is the amount of exercise i do good enough?

Well, I do pretty much nothing, and my sleep is okay, so I'd say you do a pretty good job.

Exercise is healthy but not an essential part of LDing. I get what you mean that it makes for better sleep, that's good, but don't expect a big boost in lucidity just from exercise. Some people need exercise to sleep better, some can sleep very well without any exercise, it depends on the person.