Lack of Good Sleep

As scientists learn more about the function of sleep, a growing body of research is making the connection between inadequate sleep and the increased risk of a number of health conditions, such as type II diabetes, hypertension and obesity.

One pivotal study, conducted by researchers at the University of Chicago and published in 1999 in the journal Lancet, shows that even in young, healthy people, a sleep debt of three or four hours a night over the course of a week affects the body’s ability to process carbohydrates, manage stress and maintain a proper balance of hormones.  The metabolic and endocrine functions of 11 healthy young men between the ages of 18 and 27 years were monitored during the study.  The subjects spent 16 consecutive nights in a clinical research center.  During the first three nights, they spent eight hours in bed; for the next six nights, they stayed in bed only four hours; and during the last seven nights, they stayed in bed for 12 hours.  The study found that during the second week, when the subjects were deprived of several hours’ sleep, their blood and saliva samples showed a significant loss in their ability to process glucose, prompting their bodies to produce more insulin.  As a result, the men of the study had glucose levels that were associated with a pre-diabetic state.

Of equal significance, researchers have also measured the impact of sleep deprivation on how the body regulates certain hormones, finding a link between deficiencies in these hormones and the propensity for being overweight and obesity.  One major study published in 2000 in the Journal of the American Medical Association found that lack of sleep at a younger age in men can drive down the production of growth hormone (GH) later in life.  GH plays an important role during adulthood in controlling the body’s proportions of fat and muscle, therefore, having less of the hormone as men age increases the propensity for becoming overweight and having a middle age paunch.  Adding to these findings, other studies have found a correlation between inadequate sleep and inadequate levels of the hormone leptin, which regulates the metabolism of carbohydrates.  When there are low levels of leptin, the body craves carbohydrates regardless of the amount of calories consumed.

 

 Speigel K; Leproult, R; Van Cauter. E; Impact of Sleep Debt on Metabolic and Endocrine Function, The Lancet; Vol. 354; October 23, 1999

 

 Van Cauter, E; Leproult, R; Plat, L; Age-Related Changes in Slow Wave Sleep and REM Sleep and Relationship with Growth Hormone and Cortisol Levels in Healthy Men, Journal of the American Medical Association; Vol. 284, No. 7; August 16, 2000


 

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Get Some Sleep, Grumpy!