Can I use "for which" here?

I'm writing a post, but none of below sentences sounds good to me.

This post is a record of the first five weeks that I've exercised in a gym.

or

This post is a record of the first five weeks for which I've exercised in a gym.

or

Is there any better suggestion?
Thanks in advance!

Solution 1:

"For which" does not seem good. It sounds as if you exercised because of the five weeks rather than during them.

Consider the following ways of saying what you want:

• "This post is a record of my first five weeks of working out at the gym"
• "This post is a record of the first five weeks that I've been exercising at a gym"
• "This post is a record of the first five weeks that I've exercised at a gym"
• "This post is a record of my first five weeks at the gym"