Many people, like myself, overheat while they sleep. Throughout the night, our body heat can get trapped in our mattress, leaving us uncomfortable and awake. While bedding and bedroom environment are also factors, a mattress is a huge piece of the puzzle when it comes to staying cool at night. As someone who’s dealt with this problem my whole life, I had a personal stake in figuring out what makes a mattress sleep cool and which specific models stay the coolest.