My schedule is extremely limited right now, but I want to get back into a lifting routine. Long story short, I might be able to lift between 4AM and 4:30AM. However, I would almost literally have to jump out of bed and hit the weight stack.

How soon after waking up is it "safe" to lift assuming that I want to build up to the point of doing a 5x5 again. Am I risking injury by starting to lift about 2 minutes after waking up?