I am 72 y.o. with sleep apnea who uses a CPAP machine. If I finish training within 1-2hrs before bedtime I find sleep is impossible for about 12 hours. Is this caused by enhanced serotonin levels? Is there any cure other than training earlier in the day?
I find that a real basic 15-20 min yoga routine helps me wind down. Plenty of them on youtube.
I don't train at night because I hate training when I'm already tired. As long the room and myself are not warm, I'm fairly sure I could fall asleep within 15 mins of completing a PR set of 5.