This shirt was a huge surprise to me recently on a three day hiking trip. I wear a short sleeved wool shirt for high output hiking but, in the evenings, I would change into the Ecco Hoody. I initially brought it because it is ultralight; however, I quickly realized that it does a great job blocking wind (helping me to fight the effects of convective heat loss) and was super comfortable. The material is so soft I ended up wearing it to bed that same night to help stay warm. As I have not yet hiked or run in this fabric I can only highly recommend this shirt for low output activity. It makes a great extra layer to bring on a hiking trip if the temperature drops and there is a chance you'll be in the wind. I'm sure this shirt would preform well in any exposed environment like a beach or rock face.