CHICAGO Men often lose sleep as they age, possibly inflicting changes in hormone levels that can lead to expanding waistlines, declining memories and more sleeping problems, researchers said on Tuesday.
The research on 149 healthy men, 16 to 83, suggested that helping men get more sleep could indirectly provide a form of hormone therapy that might help avert some unwanted hallmarks of ageing.
Monitoring sleep patterns and hormone levels, University of Chicago researcher Eve Van Cauter found men 36 to 50 experienced much less of the deepest "slow wave" sleep during peak secretions of human growth hormone.
The result was a 75 percent decline in levels of growth hormone from young adulthood to middle age, with fewer steep declines continuing into old age.
"While the clinical implications of decreased slow wave sleep are still unclear, the relative growth hormone deficiency of the elderly is associated with increased fat tissue and abdominal obesity, reduced muscle mass and strength, and reduced exercise capacity," Van Cauter wrote in the Journal of the American Medical Association.
By contrast, middle-age women generally do not suffer the same decreases in deep sleep in middle age as men.
The other hormone examined in the study was cortisol, which is thought to have an impact on cognition and memory and may also cause men to wake up more frequently as levels decline.
Cortisol levels fell in men older than 50 when sleep became more fragmented and less time was spent in rapid eye movement (REM) sleep when secretions of the hormone may peak.
Van Cauter wrote that offering men strategies to help them get a better sleep as they age may "represent an indirect form of hormonal therapy with possible beneficial health consequences." Marc Blackman of the Johns Hopkins University School of Medicine, writing in an accompanying editorial, said the study was the largest to date on the subject and convincingly showed parallel decreases in deep sleep and growth hormone secretion as men passed from young adulthood to middle age.
But the study left open the key question of whether sleep patterns were the cause of changes in hormone levels or vice versa, according to Blackman and other experts.
Providing men with hormone therapy might help their sleep patterns, which in turn could lift hormone levels, but that has yet to be tested, the experts said.
Growth hormone therapy, once touted as a potential fountain of youth, has produced mixed results and some unwanted side effects in older adults, said Dan Brauner, of the University of Chicago's Geriatrics Department, who was not involved in the study.
"What people push now is sleep hygiene ... where the bed is for sleeping. Don't lie in bed watching TV. Don't drink stimulants (like coffee) before going to sleep. Get out of bed at the same time every day," Brauner said.
(Reuter)