I don't swim to get rid of stress but in the end that's what happens.
I don't intentionally swim as a way of getting rid of stress but as a result I think it helps with the stress.
1) I don't swim to get rid of stress but in the end that's what happens.
「ストレス解消のために泳いでいないけど、結局はストレス解消になっている。」
get rid of stress で「ストレスを解消する」
in the end で「結局・なんだかんだで」
2) I don't intentionally swim as a way of getting rid of stress but as a result I think it helps with the stress.
「ストレス解消のために意図的に泳いでいないけど、結果的にストレス解消に役立つ。」
intentionally で「意図的に・もくろんで」
as a result で「その結果として」
help with で「（病気などを）治すのに役立つ」
ご参考になれば幸いです！
日本 
