How to stop overthinking at night?

TL;DR

To stop overthinking at night, create distance from the thought and give your body a way to wind down before your mind does:

• Ask how much the problem will really matter tomorrow morning, next week, or a year from now.
• Treat any thought that shows up between 2 and 5 a.m. as unreliable, not the truth.
• Use movement as an off switch before bed: a short walk, some stretching, or slow breathing with a long exhale.

Insights

At night, the same worry can feel far bigger than it is. One thing that helps is to travel forward in time in your head: ask yourself how much this will matter tomorrow morning, next week, or a year from now. Problems are rarely as heavy once you are fully awake, and thinking it through using your own name, instead of "I," adds a little more distance. It also helps to make a simple rule that any thought arriving in the small hours, roughly between 2 and 5 a.m., does not get to be believed, because your mind is not a reliable narrator at that hour.

The other half is your body. When your thoughts will not slow down, give your body a physical off switch before you try to sleep. A short walk, a few minutes of stretching, or slow breathing with a long, drawn-out exhale all signal your body to unwind, and your mind usually settles once it does.