Re: "... I do this exercise."
"Take exercise" is the all-encompassing generic term which includes any form of exercise.
"Do [this] exercise" in the example you gave refers to the weight-lifting exercise already mentioned.
However, sometimes the two are almost interchangeable:
How much exercise do you take on a daily basis?
How much exercise do you do on a daily basis?
Did you do a lot of exercise last week?
Did you take a lot of exercise last week?
We also say "do exercises" when talking about things like stretching, star jumps, leg lifts etc and we cannot use "take" instead in this context.
I do exercises every morning before breakfast.
We use "do" with certain sports and "take" is never appropriate:
I do karate once a week.
I do judo with a friend.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.