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Archived Comments for: Ethnicity, sleep, mood, and illumination in postmenopausal women

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  1. This could be due to increased testosterone...

    James Howard, independent biology

    24 May 2004

    It is my hypothesis that our circadian rhythms, hence sleep and consciousness, are controlled by an interaction of melatonin and DHEA (1985). During sleep, melatonin is high; during consciousness, DHEA is high. Melatonin and DHEA interact to control production of the other. When melatonin is highest, NREM sleep occurs; when DHEA increases slightly during sleep to maintain brainstem function, REM sleep occurs.

    During sleep, DHEA is low to reduce stimulation of the CNS, so sleep may occur. (DHEA is high during the day to maintain consciousness.) If the amount of DHEA during sleep is reduced too much during NREM sleep, negative phenomena may occur. One of these is SIDS (very low) and another is sleep disturbances (DHEA not quite so low). When DHEA is too low during sleep, as I suggest is the case in SIDS, the "recruitment mechanism" involving the brainstem cannot stimulate sufficient DHEA to maintain brainstem function. In sleep apnea, I suggest the recruitment mechanism is effective and may cause over-production of DHEA which disturbs sleep or may awaken the individual. DHEA naturally begins to decline around age 20, reaching very low levels in the elderly. It is this decline in DHEA which, I suggest, causes increased sleep apnea in older individuals.

    The foregoing explanation of sleep apnea may be affected by testosterone. In 1997, I first suggested testosterone increases sleep apnea because of its effects on availability of DHEA during sleep. Testosterone reduces steroid sulfatase, which reduces the conversion of DHEA sulfate, the large background source, to DHEA, the active form. Hence, men exhibit more sleep apnea than women. Kripke, et al., found that Hispanic and African-American women exhibit increased “curtailed sleep” as a result of “sleep disordered breathing.” I cannot provide data regarding testosterone levels in Hispanic women, but it is known that testosterone levels are higher in African-American women than Caucasian women. I suggest, at least in the African-American subjects of this study, that the increased curtailed sleep, as a result of sleep disordered breathing, is caused that increased testosterone in these subjects.

    The effects of supplemental testosterone on women has been examined. It was determined that “We conclude that testosterone administration increases AT [apneic threshold] in premenopausal women, suggesting that the increased breathing instability in men is related to the presence of testosterone.” (J Appl Physiol 2003; 94: 101-7)

    Competing interests

    None declared