Hello Ian,

I did not hear about such studies.  Please check a very interesting study which may be relevant to the discussion given that SWS dominates the NREM portion of the sleep cycle towards the beginning of the night, which may be  at least partially altered if bedtime occurs at a later time. Saying that,  it is currently believed that  the distribution of SWS toward the beginning of a sleep episode is not mediated by circadian processes but reflects the homeostatic system highest at the onset of sleep.

Bigard AX1, Boussif M, Chalabi H, Guezennec CY. Alterations in muscular performance and orthostatic tolerance during Ramadan.Aviat Space Environ Med. 1998;69(4):341-6.

Kind regards,

Tatyana

Wilse Webb's group at the University of Florida, Gainesville started some interesting work in which they reduced slow wave sleep with electrical stimulation during maintained sleep. I don't know much about the consequences they measured, but they were reducing sws..

Thanks James and tatyana