Imagine you and some friends are out boating on a chilly day. The wind is crisp and becoming unbearably cold. As you turn to head home, your boat tips over and everyone falls out of the boat into a freezing cold river.
What will happen to your body heat?
Because the water temperature is much lower than that of any person (about 38°C), and because water is such a good conductor for heat flow, energy as heat will flow rapidly from your body into the water.