Morning Mobility question for Steve Feides

I just read the "Morning Mobility" article which is perfect timing because I’ve been trying to come up with a quick and simple routine. I’ve been following some of the Super Joints exercises but I’ve been real careful to wait to do any of the spinal flexion type exercises until I’ve been awake for a half hour or so.

The reason (and I don’t know the exact reference or details) but I heard/read various discussions about, I believe it was Dr. McGill or Mel Siff’s (correct me please), about how our discs in our spine fill with fluid as we sleep and that this swelling makes them more at risk for injury if they are loaded early in the morning (I’m not trying to quote, so if anyone knows the actual reference and details again please correct me).

So I have been scared to do the morning bed stretching or any other flexion type exercise. If this is safe to do then please let me know what they were talking about with being careful. It could be that they just want us to not wake up, roll out of bed and get under a bar for a heavy squat!

thanks for any feedback/explanations