oh word that makes sense. you usually work out at 6am? i'd be afraid of straining every muscle in my body if i tried to mess with a barbell that early.
Maybe it's just broscience, but when we were forced to be up at 6am to for training camp in college was really when all of us went from ok to serious athlete. I've talked to enough people that have seen a striking difference in their training when they begin at sunrise that I think there could actually be something to it... It's standard practice for almost every elite athlete, again not scientific evidence - it could just be the discipline and cultural shift but I highly recommend it. It could be that...
1) Testosterone is highest at sunrise and right after waking...
2) By having your first session at 6am you can get into your day around 8 and then get a full 8-12 hours before a second session starting between 2-6pm. The second session will end long enough to before bedtime to not interfere with sleep.
3) Humans can function on less sleep when the make it up on the front end rather than the backend (some evidence to support this). What this means is that if you sleep from 2am-5am and get only 3 hours sleep, it's actually better for the long term sleep debt to make up for it by going to bed early the next night (say 8pm-5am = 9hrs sleep) rather than sleeping in 2am-11am...
4) It could just be the discipline it give you... maybe knowing you have gym in the morning at 6am is going to make it easier to feel like you don't need to have 1 or 2 or 3 beers with dinner while if your workout is at 10am you might be tempted...
Anyway, just an observation but I real think it's a good idea to attempt early morning workouts if you have the chance... Get your cup of coffee and get it in...