When we're under stress, our adrenal glands produce extra cortisol. That's what makes us feel wired at night when our minds are racing and we can't sleep.
A good low tech, low cost way to lower cortisol is to add heat to the middle back (over the adrenal glands). The heat is soothing (for most people, ymmv) and the increased blood flow normalizes cortisol production.
A warm bath, a heat mat, an electric blanket or a heat pack all work.
If you need to spool down to sleep, give it a try.