When that happens to me it's often because I'm ruminating about something, can't get it out of my mind and relax. If that's what's keeping you up, CBT (cognitive behavorial therapy) techniques can help to stop that thought pattern, or just taking some daily action (any concrete action besides just turning it over in your mind) towards resolving the thing you're thinking about can help.

White noise sometimes helps me sleep too, especially after waking up in the middle of the night.

My theory is this is cause by stress hormones.

You can get to sleep because you’re so damn exhausted, but you wake up as soon as you’re physically able because of the hormones.

The answer is exercise. Aerobic and weights. Three times a week minimum. And for a good amount of time.

I do powerlifting 3x week. No real aerobics, I should add that but I just hate it. Sometimes I’ll drop the weight and do high rep sets which does get my heart pumping.

My completely unscientific analysis: aerobics gets the blood circulating more and enables the body to remove stress hormones from the blood at a faster rate.