Exercise doesn't really work for everyone. I found when I used to have trouble sleeping, heavy lifting made my sleep 10x worse (and still messes with my sleep now when I try it every now and then). Light to moderate exercise tended to improve my sleep, but the improvement was fairly minor. CBT-I and getting some bright light in the morning, on the other hand, were complete game changers for me. I've gone from sleeping maybe 5 - 6.5 hours of poor sleep a night (waking up multiple times, early waking), to normally 7 - 8 hours of good quality sleep and the improvement has been consistent for the past few years now.