A recent study in the journal Nature Communications found depriving people of sleep for just one night increased cravings for junk food and decreased rational eating decisions in the frontal cortex.
You might be familiar with the unfortunate aftermath of a crappy night's sleep as you sheepishly order a red-velvet doughnut or gooey cheese Danish with your gargantuan morning java, sending you on a downward spiral of hunger, cravings and storing fat throughout your day as blood-sugar levels spike and crash.
Hormonal imbalances underlie these eating debacles. Simply put, lack of sleep adversely affects numerous hormones, so you're more likely to store than burn fat.
Let's look at seven fat-regulating hormones that become imbalanced with too little sleep and set the stage for fat gain, obesity and numerous diseases.
- Leptin. Leptin tells your brain that you're full and regulates metabolism so you burn more fat when your body needs to. For fat loss, you want plenty of leptin circulating, but you also want your brain to get its message. A study in The Journal of Clinical Endocrinology and Metabolism concluded sleep duration influences leptin production, which in turn adversely affects other hormones like cortisol and thyroid-stimulating hormone (TSH). Researchers concluded that "sleep modulates a major component of the neuroendocrine control of appetite."
- Ghrelin.This hormone does the opposite of leptin. Ghrelin tells your brain to eat now, and it's no coincidence the name sounds like your stomach rumbling. Increased ghrelin means you're more likely to nose dive into the glazed donuts. A study in the Journal of Sleep Research showed one night of sleep increased ghrelin levels and hunger in healthy normal-weight men, which in the long run could contribute to weight gain and obesity.
- Adiponectin. This anti-inflammatory hormone helps predict cardiovascular risk and regulates several metabolic processes including fat oxidation (breakdown). Studies show optimal adiponectin levels can reduce your risk for insulin resistance and diabetes. A study in the journal Physiology and Behavior found reduced sleep decreases adiponectin production, increasing cardiovascular risk in Caucasian women.
- Insulin. Elevated levels of this powerful storage hormone slam your fat-cell doors shut, storing fat rather than releasing it to burn. A study in The Journal of Applied Physiology concluded chronic sleep loss decreased insulin sensitivity, increased hunger and appetite and contributes to weight gain, insulin resistance and diabetes.
- Glucagon. Glucagon does the opposite of insulin. This hormone releases fat from your fat cells to burn for energy. A study in The Journal of Clinical Endocrinology and Metabolism looked at 10 men who only got 4.5 hours of sleep every night. Decreased sleep duration reduced circulating levels of glucagon.
- Cortisol. This stress hormone can benefit you in the short term but, when chronically elevated, stores fat and breaks down muscle. Cortisol levels should be highest in the morning and taper throughout the day. A 1997 study in the journal Sleep was appropriately called "Sleep loss results in an elevation of cortisol levels the next evening." Researchers concluded too little sleep could increase stress as well as metabolic and cognitive problems, not to mention leaving you tossing and turning the next night.
- Growth hormone. Your body makes this "fountain of youth" hormone during deep stage 4 sleep. Among its benefits, growth hormone (GH) aids in muscle synthesis and repair, boosts energy and improves fat metabolism. Light sleepers and people who awake often during the night might not be making optimal GH -- a 1991 study in the Journal of Psychiatry and Neuroscience showed fewer hours of sleep means your body makes less GH.
Davidson JR, et al. Growth hormone and cortisol secretion in relation to sleep and wakefulness. J Psychiatry Neurosci. 1991 July; 16(2): 96-102.
Greer SM, et al. The impact of sleep deprivation on food desire in the human brain. Nat Commun. 2013 Aug 6;4:2259. doi: 10.1038/ncomms3259.
Leproult R, et al. Sleep loss results in an elevation of cortisol levels the next evening. Sleep. 1997 Oct;20(10):865-70.
Schmid SM, et al. A single night of sleep deprivation increases ghrelin levels and feelings of hunger in normal-weight healthy men. J Sleep Res. 2008 Sep;17(3):331-4. doi: 10.1111/j.1365-2869.2008.00662.x. Epub 2008 Jun 28.
Schmid SM, et al. Mild sleep restriction acutely reduces plasma glucagon levels in healthy men. J Clin Endocrinol Metab. 2009 Dec;94(12):5169-73. doi: 10.1210/jc.2009-0969. Epub 2009 Oct 16.
Simpson NS, et al. Effects of sleep restriction on adiponectin levels in healthy men and women. Physiol Behav. 2010 Dec 2;101(5):693-8. doi: 10.1016/j.physbeh.2010.08.006. Epub 2010 Aug 17.
Spiegel K, et al. Sleep loss: a novel risk factor for insulin resistance and Type 2 diabetes. J Appl Physiol. 2005 Nov;99(5):2008-19.
Spiegel K, et al. Leptin levels are dependent on sleep duration: relationships with sympathovagal balance, carbohydrate regulation, cortisol, and thyrotropin. J Clin Endocrinol Metab. 2004 Nov;89(11):5762-71.
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