Forget the white noise machines, chamomile teas and essential oils — the key to a good night’s sleep is in the sheets. If you don’t have a good set of sheets and blankets to keep you cool and comfortable, no amount of fancy-smelling oils or expensive mattresses can help you. Research has found a correlation between high heat and bad sleep, so if you’re the type to run hot while deep in REM, you’ve probably noticed that you don’t always wake up on the right side of the bed.