Comment by rajnathani

> .. the various modifications all point in the direction of a buildup of mitochondrial electron surplus as the fundamental inducer of the need to sleep.

> The hypothesis is that aerobic respiration itself comes with the tradeoff of a required sleep state in order to catch up and restore mitochondrial function in the nervous system ..

These are the key points. Then the explanation for insomnia for people who even engage in physical activity in non-successful attempts to mitigate it is that maybe the physical activity is overly exerting the body in a way which negatively affects the diaphragm muscles (including supporting muscles) and causes lower blood circulation and inhibits passive-physical-activity mitochondrial use in the body due to lower aerobic respiration mostly, and thus the electron surplus isn't then achieved for sleep-induction (as stated in the above quoted statement).