I love to wear this to run in! It is fitted so if between sizes I would size up!
I usually wear this in as a 2nd layer with a fitted tank top under to hike, run, take walks, and really anything outside. I love I can unzip a bit when I’m hot or zip up to keep in some heat on windy days.
I also toss a vest over it! I love it isn’t too bulky!
I am 5 4, 135lbs, athletic build, and 34 B and wear a small (it is fitted).