It is common practice to say Howou are you these days instead of HOw are you those days. BUt I am wondering if "those days" is acceptable to a English language native speaker. Thanks for your comments.
Demonstrating the importance of punctuation
It is common practice to say "How are you these days?" instead of "How are you those days?"
I agree that it's reasonably common, after greeting someone you have not seen in a long time, to say "How are you these days?" especially if they were (perhaps) going through some difficulty when you last saw them. "Oh, my dog made a full recovery, my son was acquitted of all charges, and my mistress turned out not to be pregnant, so it's all good, thanks."
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
"How were you those days" is perhaps acceptable if the conversation goes something like:
A: I was sick for a week, and after that I had to pass a whole bunch of exams.
B. And how were you those days?
Meaning "And how was your health during your exams?". But it's a pretty careless usage. In any case, "those days" refers to the past, not the present.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
Yes, I did say it would be a careless usage. The thing I really wanted to point out is that "these days" marks the present or the immediate future (the formal "presently", so to speak), while "those days" marks the only the past -- and does not seem natural for the remote future, either.