Q: I read somewhere (perhaps in NROL? maybe not) that you should lift 60 minutes after you wake up because your spine fills up with fluid at night and it takes about an hour for it to go away. This fluid supposedly increasing pressure on the spine or whatever.
I hope I didn't just imagine that or something.
A: Your intervertebral discs (the nucleus pulposus specifically) are designed to be shock absorbers. They are filled with a number of different biological materials and metabolites (collagen fibers in a mucoprotein gel with polysaccharides and water) that can absorb compressive forces transmitted through the spine during daily activities. Like all of the structures in our bodies, water is absorbed and released throughout the course of the day, in this case due to the consistent compressive forces that we experience from walking upright. When we sleep, we are lying flat and there is no compressive force on the discs, allowing them to absorb water and materials without compression causing a subsequent loss of fluids. When you wake up, you're actually slightly taller than at the end of the day because of this. However, because of the increased height of the discs, your spine is less stable than when your discs have naturally been weighed down from the weight of your spine (less surface area actually making contact to the vertebrae above and below the disc). This isn't an issue...unless you're planning on performing exercise which substantially increased the forces onto the spine and intervertebral discs, in which case there is an increased risk of injury. Typically the recommendation is to wait 30-45 minutes until engaging in exercise from the time that you wake, which is naturally the minimum amount of time required to digest the morning's breakfast/pre-workout meal anyway, so again this typically isn't an issue unless a person is mistakingly engaging in fasted exercise...