Your core body temperature fluctuates so much throughout the night, and so when you overheat, this can disrupt both your REM cycle, HRV, and body's ability to recover.
So sleeping cold is ideal, and turning down the thermostat is a great place to start (aim for somewhere between 60 to 67 degrees Fahrenheit) But that's just one small factor. And so if you want to see real, significant changes to your sleep quality, you can't leave out the core component: and that is your actual bed. I personally use the Eight Sleep Pod Pro Cover because you can schedule/adjust temperature of your bed at multiple touch points throughout the night (via their app). Plus it includes a built-in thermal alarm and sleep tracking. But the Ooler and Chilipad are great affordable options as well.
Start your cooling mattress device or adjust your thermostat to 60 degrees 1-2 hours before bed
7 times per week