Lower body workout today was really energizing.  I felt very good throughout, especially on the squats.  I didn't up the weights from previous squats, but I performed the exercise a little deeper, which really adds stress. 
I have discovered that working out on an empty stomach is the right way to go.  I had a banana and a peach 1/2 hour before starting, and this worked very well.  Last Sunday, before my upper body workout, I had a green smoothie with lots of ingredients, and I suffered for it throughout the workout.  Today was A+.  I did 30 minutes of intervals at level 6 on the recumbent bike at the end.