Hey I workout at 24 hour fitness in utah and I met an x-seal who gave me a few pointers about two years ago. It definitely helped me with my swim times. I've been swimming at least half the time with a sweatshirt on and when i'm feeling like being really slow sweats too. I cut my times down to 8:30 for swimming and definitely became a lot more comfortable in the water. Another thing you can do to get more comfortable in the water is throw the sweatshirt in the middle or on the opposite side of the pool, swim under water and put it on and take it off all while under. The distance really doesn't it matter, it just depends on how much lung capacity you have and if you are with a swim buddy. Good luck, I definitely have some fun doing this, hope it helps someone else out too.