Hormones and Sleep

Does lack of sleep disrupt hormone balance, or does hormone imbalance disrupt sleep?  Both may exert an influence on sleep patterns, however, there is strong evidence that hormone imbalance disrupts sleep, for  around the time of pregnancy, perimenopause, post menopause, sleep problems are prevalent. Also as people age, sleep patterns change markedly, and this also may be associated with a drop in hormone levels.

It has been reported by researchers from the University of Chicago that quality of sleep begins to deteriorate much earlier than previously thought, and it was found that " changes in sleep were mirrored by changes in hormone secretion".August 16, 2000 JAMA.

The study involved 149 men aged 16 to 83, found that although quantity of sleep in young adults ( 16 to 25) remained the same, the proportion of

slow wave or deep sleep decreased significantly as the young adult reached mid-life( 35 to 50). The decrease in deep sleep resulted in reduced levels of growth hormone secretion.

There were two stages involved in the sleep deterioration, the first began in early adulthood ( 16 to25) and the second stage occurs after 50. Late life changes in sleep involved decreased total sleep time, more frequent periods of awakenings throughout the night, and considerable reduction in REM sleep.What was noted in the study was that loss of REM sleep was associated with " elevated evening levels of cortisol".

Hormonal changes in women as they age appear to be associated with much lighter sleep, they take longer to fall asleep, and have more sleep disturbances with frequent awakenings. Increased weight around menopause may increase the likelihood of upper airway obstruction, leading to obstructive sleep apnea.

The fact that disruption to sleep patterns occurs around the time of menopause does indicate that both estrogen and progesterone levels play a significant role in sleep. Decreased estrogen level during menopause has been associated with snoring and obstructive sleep apnea. Menstruation-related sleep disorder demonstrates the influence fluctuating hormone levels have on sleep patterns, premenstrual insomnia disappears shortly after menstruation begins.

There have been other studies done focusing on the effect sleep deprivation has on bodily functions. A study done by Van Cauter and colleagues found that :" the metabolic and endocrine changes resulting from a significant sleep debt mimic many of the hallmarks of aging". One study used 11 healthy young men as subjects and tracked them for 16 consecutive nights , subjecting them to various alterations in sleep deprivation patterns.

" They found profound alterations of glucose metabolism, in some situations resembling patients with type-2 diabetes, during sleep deprivation". The study found that sleep deprivation also altered " the production and action of other hormones, dampening the secretion of thyroid stimulating hormone, and increasing blood levels of cortisol, especially during the afternoon and evening". " Elevated evening levels of cortisol are typical of much older subjects and are thought to be related to age-related health    problems such as insulin resistance and memory impairement".

Read more:Sleep debt

References:

The Journal of the American Medical Association August 16, 2000; 284; 861-868, 880-881.

Spiegel K, Leproult R, Van Cauter E, Impact of sleep debt on metabolic and endocrine function. Lancet 1999; 354: 1435-1439. Abstract.