medium I'm 5'10 180 and it fits me good with room for layers under

BEWARE!! Vizzy285's report led me to believe a size Medium would be fine for me, since my stats are 5'9 165lbs currently. I got the medium and I felt like I just pulled a wool sweater from the baby gap out of the dryer after first wash. It "fit" but barely...so I suppose it depends on your build, I got like a 44" chest and I guess my arms and torso are kind of long but I thought I'ma pretty average build. Definitely got the impression that moving around, the protection would be skirted due to the arms hiking up or the waist band hiking up from activity. I'm going with a Large and I strongly urge others to do the same unless they like a very tight fit with little room for movement.