Sleep and weight

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Sleep Deprivation and Type 2 Diabetes[edit]

Baseline levels of insulin do not signal muscle and fat cells to absorb glucose. When glucose levels are elevated, the pancreas responds by releasing insulin. Blood sugar will then rapidly drop. This can progress to type 2 diabetes.

Sleep loss can affect the basic metabolic functions of storing carbohydrates and regulating hormones. Reduction of sleep from eight hours to four hours produces changes in glucose tolerance and endocrine function. Researchers from the University of Chicago Medical Center followed 11 healthy young men for 16 consecutive nights. The first 3 nights, the young men slept for the normal 8 hours. The next 6 nights, they slept for 4 hours. The next 7 nights, they spent 12 hours in bed. They all had the same diet. They found that there were changes in glucose metabolism that resemble that of type 2 diabetes patients. When the participants were tested after sleep deprivation, they took 40% longer than normal to regulate blood sugar levels after a high-carbohydrate meals. The secretion of insulin and the body's response to insulin decrease by 30%. Sleep deprivation also alters the productions of hormones, lowering the secretion of thyroid stimulating hormone and increasing blood levels of cortisol.[1][unreliable medical source?]

It has also been shown that when slow-wave sleep was suppressed for three nights, young healthy subjects were 25% less sensitive to insulin. They needed more insulin to get rid of the same amount of glucose. If the body does not release more insulin to compensate, the blood-glucose levels will increase. This resembles impaired glucose tolerance, which can result in type 2 diabetes.[1][unreliable medical source?]

Lack of Sleep Related to Weight Gain[edit]

Lack of sleep has been strongly associated with weight gain in a variety of studies[2] across all ages, though research suggests children and adolescents are particularly vulnerable.[3][4] Sleep deprivation is believed to influence the brain's response to high-calorie food, making it more attractive, while also affecting the production of hormones that control appetite.

Matthew P Walker, a psychology and neuroscience professor at UC Berkley, published a study during which the participants were deprived of sleep for one night. The New York Times summarized his study as such, "On days when the subjects had not had proper sleep, fattening foods like potato chips and sweets stimulated stronger responses in a part of the brain that helps govern the motivation to eat. But at the same time, the subjects experienced a sharp reduction in activity in the frontal cortex, a higher level part of the brain where consequences are weighted and rational decisions are made.”[3] A brain that has been deprived of sleep for one night is more likely to respond more intensely to junk food but also has the decreased ability to curb that desire. These results were consistent even as the subjects were given extra calories to compensate for the amount of energy expended during those extra hours that the subjects stayed awake, which indicates that one’s craving for junk food is not a response to offset an energy deficit.[5] Walker further speculates that one of the biological basis for this reaction could the buildup of adenosine, a metabolic byproduct that may degrade communication between networks in the brain. Adenosine is cleared from the brain during sleep.[3]

Previous research by the University of Chicago had also associated short sleep with an increase in calorie consumption from snacks, albeit with no change in overall calorie intake, hormone levels or energy expenditure across the different sleep schedules tested.[6] A 2014 review of studies on the link between sleep debt and obesity also reported no association between short sleep duration and total energy expenditure.[4]

Another explanation of the relationship stems from the balance between two hormones, leptin and ghrelin, which act on the nuclei of the hypothalamus to monitor energy and food intake. Leptin primarily inhibits appetite while ghrelin, which is the released by the stomach, works to stimulate appetite. Sleep deprivation has been associated with increased levels of ghrelin and decreased levels of leptin in multiple studies.[7] In addition to the hormonal variation, other research has also associated shortened sleep durations with a proportional increase in subjects' BMIs.[8]

Metabolism

Metabolism involves two biochemical processes that occur in living organisms. The first is anabolism, which refers to the buildup of molecules. The second is catabolism, the breakdown of molecules. These two processes work to regulate the amount of energy the body uses to maintain itself. During non-REM sleep, metabolic rate and brain temperature are lowered to deal with damages that may have occurred during time of wakefulness.[9]

Sleep is important in regulating metabolism. Mammalian sleep can be sub-divided into two distinct phases - REM (rapid eye movement) and non-REM (NREM) sleep. In humans, NREM sleep has four stages, where the third and fourth stages are considered slow-wave sleep (SWS). SWS is considered deep sleep, when metabolism is least active.[10] In normal metabolic function, the pancreas releases insulin after blood glucose levels raise. Insulin signals muscle and fat cells to absorb glucose from food. As a result, blood glucose levels return to normal.

Sleep loss can affect the basic metabolic functions of storing carbohydrates and regulating hormones. Reduction of sleep from eight hours to four hours produces changes in glucose tolerance and endocrine function. Researchers from the University of Chicago Medical Center followed 11 healthy young men for 16 consecutive nights. The first 3 nights, the young men slept for the normal 8 hours. The next 6 nights, they slept for 4 hours. The next 7 nights, they spent 12 hours in bed. They all had the same diet. They found that there were changes in glucose metabolism that resemble that of type 2 diabetes patients. When the participants were tested after sleep deprivation, they took 40% longer than normal to regulate blood sugar levels after a high-carbohydrate meals. The secretion of insulin and the body's response to insulin decrease by 30%. Sleep deprivation also alters the productions of hormones, lowering the secretion of thyroid stimulating hormone and increasing blood levels of cortisol.[11][unreliable medical source?]

Can Sleeping More promote Weight Loss?[edit]

A regular sleep schedule can be a vital piece to increasing weight loss. While it is important to sleep more than an average of 6.5 hours per night, sleeping over 8.5 hours per night has been shown to contribute negatively to weight loss. Getting adequate sleep can also help account for any excess snacking that occurs throughout the course of the day due to feeling lethargic.[12]

According to a recent study at Brigham Young University, a regular sleep schedule can make an almost immediate difference on the body’s ability to metabolize fat cells. In this specific study design, 300 college aged women (19–26 years old) were followed for a week and given an activity tracker which not only monitored movements, but also sleep patterns. The study also found that participants with lower BMI had higher quality of sleep, while those with higher BMI’s had lower quality of sleep. But was the reverse relationship also true?

While health professionals almost unanimously agree that if an individual is already getting 8 hours of sleep, then another half hour won’t make them lose weight; however, in cases where a person is used to getting 5 hours of sleep per night and they start getting 7–8 hours, it is common to see them start to shed pounds, especially in obese individuals. What causes this phenomenon? Two hormones, ghrelin and leptin, closely associated with appetite are key in the sleep and weight relationship.[13] Ghrelin is the hormone that controls appetite and tells the body when to eat, and when one is sleep-deprived, they have more ghrelin. Leptin on the other hand, is the hormone that tells one to stop eating, and when an individuals is sleep deprived, they have less leptin. In order to keep these hormone levels in balance, a person needs to get adequate sleep so they do not feel the need to excessively eat in an effort to gain energy and reduce fatigue.

Effect of Oversleeping[edit]

There have been many connections made between oversleeping and certain disorders. Many of these have been made without any identifiable reason for correlation, and are mainly observational. WebMD reports that sleep apnea may cause oversleeping because of disruptions in the normal sleep cycle, that individuals who sleep more may be more prone to headaches because of neurotransmitters imbalances, back pain can increase with oversleeping because a certain level of physical activity is not being maintained, and that oversleeping may be correlated with depression and higher death rates.[14]

However, these connections have not been subject to rigorous examination. On the other hand, there have been studies that have looked into the potential physical side effects of oversleeping on weight and weight – related conditions. One study at Université Laval's Faculty of Medicine in Quebec studied the life habits of 276 subjects over a 6-year period and found that about 20% of those with long (9+ hours) of sleeping time developed type 2 diabetes or impaired glucose tolerance as compared to 7% in those that slept an average amount of time.[15] A further look into the 6-year Quebec Family Study demonstrates that long-duration sleepers (9–10 hours) were 25% more likely to experience a 5-kg weight gain, and a 21% increase in risk of obesity, when adjusted for age, sex, and baseline BMI, as compared to average duration sleepers (7–8 hours) (NCBI). Even when the researchers adjusted for energy expenditure and physical activity levels (among other covariates), these relationships remained significant. The researcher’s results indicate a U-shaped relationship between hours of sleep and type 2 diabetes, coronary heart disease and weight, but the metabolic mechanisms affected by long sleep duration are less clear than with sleep restriction and remain somewhat speculative.[15]

A Nurses’ Health Study analyzed a group of about 72,000 US women who did not report having coronary heart disease at the onset of the study, and assessed the relationship between their reported sleep durations and incidence of a CHD event over a period of 10 years (JAMA). At the conclusion of the study, the data indicated that women who slept a longer duration (9–11 hours) were 38% more likely to have CHD than women who slept 8 hours. However, the researchers had no plausible explanation for a cause-and-effect relationship [16]

Obesity Related Sleep Disorders[edit]

Sleep apnea

Obstructive Sleep Apnea

Sleep apnea is a sleep disorder which causes an individual to have short pauses in breathing or very shallow breaths while sleeping. These pauses in breathing can often cause the individual to wake up, snore, choke, or just generally disrupt their sleep.[17] As a result, sufferers of the disease do not get quality sleep during the night and are tired during the daytime. Sleep apnea is very difficult to diagnose because doctors can’t exactly tell if a person has sleep apnea in a regular routine visit. Additionally the patient himself may not even realize he has sleep apnea because it occurs during sleep, so a partner or roommate is usually the first to notice symptoms. There are two types of sleep apnea, obstructive and central. Obstructive sleep apnea is more common among overweight patients, and occurs when the airway is fully or partially blocked at times during sleep. Any air that does sneak by the blocked passage can cause loud snoring. The second type of sleep apnea, central sleep apnea, is much more rare and has to do with the part of the brain that regulates breathing. The signal from the brain to the lungs is disrupted, resulting in pauses in breathing. Treating obstructive sleep apnea is much easier than central sleep apnea, and the treatment plan may include things such as lifestyle changes, mouthpieces, surgery, and breathing devices[18]

Sleep in the Media[edit]

As obesity has become an issue of nationwide focus, all forms of media have begun to explore and report on the link between sleep and weight. The coverage spans from articles in Women’s Health Magazine on “6 Ways Sleep Can Help you Lose Weight,” to NPR’s story on the research linking a lack of sleep to obesity, to Harvard School of Public Health’s discussion of sleep as an “obesity prevention source” on their site.[19][20][21] No matter how diverse the range of broadcasting, media sources seem to agree that, for whatever reasons, sleep is an important part of maintaining a healthy weight, and could be an effective approach to the obesity epidemic.

References[edit]

  1. ^ a b "Lack of Deep Sleep May Increase Risk of Type 2 Diabetes". Science Daily. Retrieved November 30, 2011. 
  2. ^ Schraer, Rachel; D'Urso, Joey (28 October 2017). "10 charts that show why sleep is so important". BBC News. Retrieved 28 October 2017. 
  3. ^ a b c O'Connor, Anahad. "How Sleep Loss Adds to Weight Gain". Well. Retrieved 28 October 2017. 
  4. ^ a b Bayon, Virginie; Leger, Damien; Gomez-Merino, Danielle; Vecchierini, Marie-Françoise; Chennaoui, Mounir (11 July 2014). "Sleep debt and obesity". Annals of Medicine. 46 (5): 264–272. doi:10.3109/07853890.2014.931103. 
  5. ^ Greer, Stephanie M.; Goldstein, Andrea N.; Walker, Matthew P. (6 August 2013). "The impact of sleep deprivation on food desire in the human brain". Nature Communications. 4. doi:10.1038/ncomms3259. 
  6. ^ Nedeltcheva, A. V; Kilkus, J. M; Imperial, J.; Kasza, K.; Schoeller, D. A; Penev, P. D (3 December 2008). "Sleep curtailment is accompanied by increased intake of calories from snacks". American Journal of Clinical Nutrition. 89 (1): 126–133. doi:10.3945/ajcn.2008.26574. PMC 2615460Freely accessible. 
  7. ^ Sharma, Sunil; Kavuru, Mani (2010). "Sleep and Metabolism: An Overview". International Journal of Endocrinology. 2010: 1–12. doi:10.1155/2010/270832. 
  8. ^ Taheri, Shahrad; Lin, Ling; Austin, Diane; Young, Terry; Mignot, Emmanuel; Froguel, Philippe (7 December 2004). "Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index". PLoS Medicine. 1 (3): e62. doi:10.1371/journal.pmed.0010062. 
  9. ^ Walker, Matthew (October 10, 2011). "Sleep Deprivation I: Immune Function and Metabolism".
  10. ^ Sharma, Sunil; Kavuru, Mani (2 August 2010). "Sleep and Metabolism: Overview". International Journal of Endocrinology. Retrieved November 29, 2011.
  11. ^ "Lack of Deep Sleep May Increase Risk of Type 2 Diabetes". Science Daily. Retrieved November 24, 2014.
  12. ^ https://www.forbes.com/sites/melaniehaiken/2013/11/21/easiest-weight-loss-tip-ever-change-your-sleep-schedule/
  13. ^ Sawamoto, R. "Higher Sleep Fragmentation Predicts a Lower Magnitude of Weight Loss in Overweight and Obese Women Participating in a Weight-loss Intervention." Nutrition and Diabetes 144 (2014): 1-6. PubMed. Web. 17 Nov. 2014
  14. ^ "Oversleeping Side Effects: Is Too Much Sleep Harmful?" WebMD. 22 Nov. 2014
  15. ^ a b Chaput, Jean-Philippe Chaput. "Sleep Duration as a Risk Factor for the Development of Type 2 Diabetes or Impaired Glucose Tolerance: Analyses of the Quebec Family Study." Sleep Medicine 10.8 (2009): 919-24. PubMed. 20 Nov. 2014.
  16. ^ Ayas, Najib T. "A Prospective Study of Sleep Duration and Coronary Heart Disease in Women." Arch Intern Medicine (2003): 205-09. PubMed. Web. 16 Nov. 2014
  17. ^ "Obesity and Sleep." Sleep Foundation. Accessed 22 Nov. 2014.
  18. ^ http://www.nhlbi.nih.gov/health/health-topics/topics/sleepapnea/
  19. ^ Merz, Julia. “6 Ways Sleep Can Help You Lose Weight” Women’s Health 18 July 2014
  20. ^ NeighMond, Patti. Report Links Lack of Sleep and Obesity. NPR. 7 Dec. 2004. Radio.
  21. ^ “Sleep” Obesity Prevention Source. Harvard School of Public Health, 2014. Web.