sleep cycles

Might be annectodal, but I track my sleep with my phone because of some sleep issues... I have very mild apnea only when sleeping on my back... so instead of a CPAP I sleep on my side... lol I still wake up 3 - 4 time a night but fall right back to sleep... Now I have been lowering my dose...

I wake up with an erection at 3am every morning, rock hard.. Usually have to masturbate to get some sleep.. Would i be better off training at this testosterone peak at 3am or battling to get back to sleep and ignore it and continue to train around mid morning or evenings... 49 year old male on...

I noticed since starting creatine supplements, my time spent in core sleep has increased. I have been working out harder on certain days. Why am I spending more time in core sleep versus the other sleep cycles?