Does this medium-firm mattress sleep hot?

No, it runs cool, scoring 8.8 out of 10 on cooling with settled surface temperature around 30 degrees Celsius. The cooling is built into the structure: 0.75 inch of gel-infused foam draws heat off the surface, and beneath it the 884 pocketed coils leave the core open for air to circulate instead of trapping it in dense foam. You wake without the overheated, sticky feeling common on all-foam beds that hold body heat.