I just learned my lesson today... I live in NH where it tends to be cold. When I was younger my mom and I always used to brave the slightly colder mountain lake waters early, just when it started warming up just enough. I hadn't actually had a chance to do this in years. I'm 24 now and I was diagnosed with Fibromyalgia just last year. Since we hadn't been swimming hardly at all last few summers I was so intent on getting out to go swimming as soon as possible this summer. Thinking swimming would be a good low-intensive exercise I could actually manage and enjoy, I looked forward to it so much. It would be my first time "really" swimming since I started having Fibro symptoms. We've had a worse summer this year, coming very slowly. It was in the 80s yesterday and today so my husband and I went up to the lake to swim. A few people were already braving it, so we tried it. The cold water kind of shocked me at first, but I knew in the past it took time to get used to cold water anyway. So thinking it shouldn't be too bad I slowly waded my way in. It took longer than usual for my body to get used to it. I noticed I started aching a little, but I was so intent on not letting the swimming trip go to waste. There's a little rock not far out from shore I used to love to swim to, so I wanted to at least do that much, and when I got to it I could at least bask in the sun. When I kicked out to swim, a sudden pain shot through my leg and arm muscles and it felt like it wanted to lock up but I pushed through it and managed to make it to the rock. When I got to the rock my body didn't seem to want to work like it used to. I actually had a very hard time pulling myself up unto the rock, it was a strange feeling. When my husband got there he helped me. I tried to warm up by basking the sunlight next to him, but instead of warming up I started experiencing a kind of delayed shivering that only seemed to get worse. All I could think of was getting back to shore and drying off and putting warm clothes back on. I told my husband I was too cold and slid back in the water, enduring through it enough to make it back to shore. I couldn't seem to wrap up quick enough and rushed back into the car, which was suffocatingly hot, but that felt like what I needed to warm up. My husband tried to hang out in the car with me as I warmed up, but he couldn't stand the heat. I on the other hand couldn't stand to get out of the heat, I was still shivering trying to warm up. Even the slight breeze that came in when he rolled down the car window pierced right to my bone. It seemed to take forever for me to warm up and I wasn't completely comfortable until I was home and absolutely dry again, despite the heat of the day. Now I'm trying to relax and I feel more exhausted than ever, as if I just finished biking a marathon. And my whole body feels bruised inside and out, even typing right now hurts. I've never felt anything like this before after swimming so I know it's because of the Fibro. So I would definitely say that cold water is not good for Fibro. I'm sure I'll be paying for this one for a while now, lesson learned. It really sucks having to suffer these things at such a young age... but I try not to let it ruin me, I just have to find out what my limits are.