[__MatrixMan__]

> I take magnesium because I am very active and have suffered for the last year or so from hypnic jerks, which are terrifying but have gone away since I started taking magnesium supplements before bed.

I'm guessing you're taking magnesium L-threonate (Sometimes goes by Magtein). If not, it's worth a try.

> I've also started cold showers when waking up (60 seconds of cold to end my shower, working towards 2 minutes).

I do something similar. 3-min cold showers in the morning, yoga to regain the heat, then meditation, then breakfast. I feel it's relevant to my struggles with attention (doesn't throw me off like adderall does)

Best I ever slept was when I was cycling 45 minutes to and from work every day. It looks like you're doing quite a lot (of the same things I do) but if you're interested in throwing more in there... there's soemthing magical about the kind of cardio that lets you explore your limits.