The body requires slow-wave, or deep restorative, sleep to maintain health. Slow-wave sleep occurs more than half of the night in humans with long or short sleep patterns. The metabolic changes leading to type 2 diabetes, generally associated with older adults and the overweight population, has been linked to the sleep deprivation of deep restorative sleep.
Sleep Stages
Sleep occurs in two main stages: REM, or rapid eye movement sleep, and non-REM sleep, also known as slow-wave sleep (SWS). REM sleep causes high electrical activity in the brain, similar to the waking state, with vivid dreaming taking place. About 75 to 80 percent of sleep time of adults is spent in slow-wave, non-REM, sleep. Slow-wave sleep progresses through 4 stages with stage 1 being the lightest sleep and stage 4 being the deepest sleep.
Importance of Sleep Stages
A study published in the "American Journal of Psychiatry" discusses the body's need for slow-wave sleep as it relates to REM sleep. The study reports slow-wave sleep occurs in those who sleep shorter hours and those who sleep longer in relatively equal amounts of time. The study goes on the say that the body has a constant need for slow-wave sleep, whereas REM sleep differs with personality and life style.
Type 2 Diabetes
Diabetes results when the pancreas does not produce the hormone, insulin or does not produce enough insulin, which results in an increase in blood glucose levels. Type 2 diabetes accounts for 85 percent of all diabetes cases with 90 percent of those people being overweight, according to the World Health Organization. Health care focuses on dietary changes, reducing weight and increasing exercise as a means to thwart development of this type of diabetes.
Sleep Study
The potential risk of this age-associated disease has been linked to sleep deprivation in a study performed by University of Chicago researchers. Deprivation of slow-wave, or deep restorative, sleep increased blood glucose levels in healthy men and women subjects aged 20 to 31, the study reports. The subjects were disturbed by noises, not loud enough to cause a full awakening, during slow-wave sleep. The study reports that 90 percent of slow-wave sleep was lost each night in all subjects shifting the sleep pattern from deep to light sleep for most of the night, each night of the study.
Sleep Loss and Insulin
University of Chicago Medical Center researchers administered intravenous glucose to the sleep subjects after each night of slow-wave sleep deprivation. After only three nights of slow-wave disturbances, insulin sensitivity decreased 25 percent, demonstrating an increase in the insulin the body needed to breakdown the glucose. Typical of aging, chronic shallow restorative sleep may contribute to metabolic changes as seen in type 2 diabetes, the report states.
References
- Merck Manuals: Introduction to Sleep Disorders
- The American Journal of Psychiatry: Sleep Need: How Much Sleep and What Kind?
- University of Maryland Medical Center: What is Diabetes?
- World Health Organization: Obesity and Overweight
- University of Chicago Medical Center: Lack of Deep Sleep May Increase Risk of Type 2 Diabetes
