Today I went on a scientific swimming trip - I went to the pool to test whether something works. I also forgot my goggles.
I tried hyperventilating before getting in the cold pool and then going completely underwater. It worked - no contractions. However, my happiness was short-lived because about 30 seconds later I started swimming and the contractions kicked in with tremendous force.
Pete, your theory was correct!
I am glad to know what the problem is, but I still react very badly to cold water. The cold itself isn't as bad as it was because I have got used to it, so I don't shiver as much as before, but the contractions remain excruciatingly strong. They only last for the first few minutes, but that's enough for me!
Lucia