Does GHRH supplementation affect GH secretion cognition mood and sleep?
Elderly individuals often experience lack of sleep at night and feel tired during the day. This may be attributed to the near total loss of slow-wave sleep (stage N3 or “deep sleep”). Of interest, the periods of slow-wave sleep in younger individuals coincide exactly with the nighttime peaks of GH secretion. Indeed, animal and some human data have suggested that appropriately timed GHRH supplementation may restart pulsatile GH secretion and stimulate slow-wave sleep. Also, limited evidence suggests that chronic GHRH supplementation may improve cognitive function, specifically psychomotor and perceptual processing speed, as well as fluid memory. One small randomized, double-blind, placebo-controlled trial of older adults (mean age of 68 years) examined the effects of 20 weeks of daily subcutaneous injections of tesamorelin (a GHRH analogue currently only FDA approved for the treatment of human immunodeficiency virus–associated lipodystrophy) on cognition, mood, and sleep in those with mild cognitive impairment (MCI) versus healthy controls. Intention-to-treat and more complete analyses revealed the favorable effects of GHRH on cognition in both healthy older adults and in those with MCI; the beneficial effect was particularly noteworthy for executive function, with a trend toward benefit on verbal memory, but there was no difference in visual memory. GHRH did not affect mood or sleep quality in healthy older adults or in those with MCI. Larger studies of longer duration are needed to further establish the role for GHRH therapy in promoting cognition, mood, and sleep in the elderly with normal or pathologic aging.