I'm up at 4:30 too so that I can get my workout in before the day starts. I have to have it before work, otherwise this perimenopausal brain would go bonkers.

Oddly enough, I find that a good weight training session is just as good as an aerobic session for getting endorphins going. Right now, I'm just building weight training base again - 12 reps & compound exercises, to get my tendons & ligaments used to the weight. After another week, I'll start to ramp up the weight and tone down the reps.