I'm tired because I haven't slept much. - why not Present Perfect Continuous?

[mrwroc]

Present Perfect Continuous - we use it when we want to express that a completed action had an unwanted side effect, examples:
I'm out of breath because I've been running.
She’s tired because she’s been working hard.


But I have found somewhere a below sentence:
I'm tired because I haven't slept much.

Can I change it to (according to the above rule):
I'm tired because I haven't been sleeping much.
? What is the difference?

 

[GoesStation]

You can. Sentence one means that you haven't had a lot of sleep recently, like just last night. Sentence two means you've repeatedly had trouble sleeping for a more extended period of time.