I was speaking for myself on that last one, from experience I can stand in a swimming pool 70 degree, chest high and start exercising. After a bit, my forehead and hair will be wet from sweat, not water. I assume I will have the same issue with this vest but my legs, arms, head will sweat. The cool feeling someone my feel with the vest, may cause them to mistakenly think they can do more then normal. It is not worth the attempt for me, maybe on one of my bike rides, it might be nice.