Strange Brain fog/energy correlation

[Therunningman]

does anyone have the symptoms where on days where you have decent energy, your brain fog and concentration are worse? Then when you have poor energy and are feeling week, your brain fog is minimal and concentration better! This is happening to me daily and on alternating days. I wonder why this is?

 

[Wishful]

I'm one of the people who have mental lethargy but not physical lethargy from ME. On days when I don't feel I have the energy to do physical activities, it's the lack of mental energy to overcome the perceived muscle aches and other aspects of physical exertion. My favourite way of describing it is that my legs have the energy for a 40 km bike ride, but my head just wants to flop down on a fluffy pillow (Go ahead and pedal. Wake me when we get there.).

That doesn't really answer your question, but it does show that there is a wide range of symptoms and relations between them.