The present study examined age-related changes from
young adult life to senescence, in the GH surge and in the
cortisol nadir at the beginning of nocturnal sleep. At present,
little is known about the time course of these changes
although this might be of considerable clinical and therapeutic
relevance (14). A decrease in SWS and REM sleep in the
aged, which has been well established (6,7), might be
associated with age-related changes in hormone secretory
activity during sleep. For these purposes, besides the cortisol
and GH secretory activity, sleep parameters were measured
within a wide range of age (20 to 92 yr).