How effective is NuvaRing?

My dr. told me that it is safe to use in the pool. I'm a competitive diver so I spend a lot of time in the water, and in hot tubs between my dives. I was concerned not only about the pool water, but also the 100+ degree water in the tubs (you are supposed to use cool to lukewarm water to rinse your ring) and he said that neither would cause a problem

It's inside your body. Your body is pretty good at regulating its own temperature because we're mammals not frogs, so it's not like it goes up or down that much if you're in a hot tub or cold pool.
no, the chlorine in the pool does not effect NuvaRing once you put it in yourself.