When carlos first jumped into the pool he though the water was very cold although the actual temperature of the pool remained constant aftera few minutescarlos no longercomplained about feeling cold this change is his reaction to the temperature of the water is an exmple

His body started to adapts with the temperature of the water, Our body does  that to save yourself from going into a panic attack or a shock. Or when we get into a hot shower or bathtub it's hot at first but we immune to it until we have to get out then everything feels like a winter storm when we look for a towel

the more fit you are, the faster the recovery. your heart rate drops most sharply in the first minute after you stop exercising; it should then fall about 20 beats a minute—a drop of less than 12 beats a minute is considered abnormal. this “recovery heart rate” is measured as part of an exercise stress test.