WEBVTT - Can Losing Sleep Make You Gain Weight?

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<v Speaker 1>Welcome to brain Stuff from How Stuff Works Hi brain

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<v Speaker 1>Stuff Lorn vogelbaumb here. An increasing number of studies are

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<v Speaker 1>finding a direct connection between sleep deprivation and weight gain. Generally,

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<v Speaker 1>people who get at least seven hours of sleep per

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<v Speaker 1>night have less body fat than people who don't. There are,

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<v Speaker 1>of course, other factors involved in determining who will become

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<v Speaker 1>overweight and who will not like food and take exercise

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<v Speaker 1>and genetics, but sleep is a more integral part of

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<v Speaker 1>the process than most people realize. In a study involving

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<v Speaker 1>nine thousand subjects between nine two and four, researchers found

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<v Speaker 1>that people who averaged six hours of sleep per night

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<v Speaker 1>were twenty seven percent more likely to be overweight than

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<v Speaker 1>their seven to nine our counterparts, and those averaging five

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<v Speaker 1>hours of sleep per night were seventy three percent more

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<v Speaker 1>likely to be overweight. Many people who are sleep deprived

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<v Speaker 1>don't even know it. Lots of us think that there's

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<v Speaker 1>quite a bit of give and how much sleep a

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<v Speaker 1>person needs to be healthy and well functioning, but most

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<v Speaker 1>researchers disagree, putting seven hours as the minimum for everyone

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<v Speaker 1>except the very young and the very old. Besides straight numbers,

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<v Speaker 1>there are a couple ways to tell if you're sleep deprived,

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<v Speaker 1>including how fast you fall asleep at night. Most non

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<v Speaker 1>sleep deprived people take about fifteen minutes to fall asleep.

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<v Speaker 1>Falling asleep almost instantly, along with chronic sleepiness, is a

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<v Speaker 1>good indicator that you're not getting enough sleep. If you

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<v Speaker 1>are sleep deprived, there are some obvious tie ins to obesity,

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<v Speaker 1>like your sleepiness making physical activity less likely, but there

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<v Speaker 1>are also a number of things going on in your

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<v Speaker 1>body that could contribute to weight gain. In scientific studies,

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<v Speaker 1>the most commonly sided effects of sleep deprivation are hormonal disturbances,

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<v Speaker 1>specifically involving the hormones lepton and grellin. When you don't

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<v Speaker 1>get enough sleep, your body has too little leptin and

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<v Speaker 1>too much grellin. Let's unpack that the hormone leptin is

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<v Speaker 1>intricately involved in the regulation of appetite, metabolism and calorie burning.

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<v Speaker 1>It's the chemical that tells your brain when you're full,

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<v Speaker 1>when it should start burning up calories, and by extension,

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<v Speaker 1>when it should create energy for your body to use.

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<v Speaker 1>It triggers a series of messages and responses that starts

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<v Speaker 1>in the hypothalamus and ends in the thyroid. Gland. The

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<v Speaker 1>thyroid gland controls the way your body stores and uses energy.

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<v Speaker 1>During sleep, leptin levels increase, telling your brain you have

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<v Speaker 1>plenty of energy for the time being and that there's

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<v Speaker 1>no need to trigger the feeling of hunger or the

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<v Speaker 1>burning of calories. When you don't get enough sleep, you

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<v Speaker 1>end up with two little leptin in your body, which,

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<v Speaker 1>through a series of steps, makes your brain think you

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<v Speaker 1>don't have enough energy for your needs. So your brain

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<v Speaker 1>tells you you're hungry even though you don't actually need

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<v Speaker 1>food at that time, and it takes steps to store

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<v Speaker 1>the calories you eat as fat so you'll have enough

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<v Speaker 1>energy the next time you need it. The decrease in

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<v Speaker 1>leptin brought on by sleep deprivation can result in a

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<v Speaker 1>constant feeling of hunger and a general slow down of

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<v Speaker 1>your metabolism. The other hormone found to be related to

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<v Speaker 1>sleep and wait is grellan. The purpose of grellin is

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<v Speaker 1>basically the exact opposite of lept in. It tells your

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<v Speaker 1>brain when you need to eat, when it should stop

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<v Speaker 1>burning calories, and when it should store energy as fat.

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<v Speaker 1>During sleep, levels of grellan decrease because sleep requires far

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<v Speaker 1>less energy than being awake. People who don't sleep enough

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<v Speaker 1>end up with too much grellan in their system, so

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<v Speaker 1>the body thinks it's hungry and it needs more calories,

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<v Speaker 1>and it stops burning those calories because it thinks there's

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<v Speaker 1>a shortage. Some scientists hypothesize that these hormonal changes that

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<v Speaker 1>occur during sleep are the result of an evolutionary process

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<v Speaker 1>that favored humans who could survive the food shortages of winters.

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<v Speaker 1>Traditionally speaking, winters have long nights and little food, and

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<v Speaker 1>summers have short nights and an abundance of food. With

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<v Speaker 1>shorter nights comes less sleep, less leptin, and more grellin,

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<v Speaker 1>making the body eat as much as possible and save

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<v Speaker 1>those calories for the long winter ahead. With winter comes

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<v Speaker 1>more sleep, meaning more leptin and less grellin, both of

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<v Speaker 1>which tell the body it's time to burn those calories

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<v Speaker 1>it's stored during the summer. Sleep deprivation has also been

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<v Speaker 1>ound to increased levels of stress hormones and resistance to insulin,

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<v Speaker 1>both of which can contribute to weight gain. Insulin resistance

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<v Speaker 1>can also lead to type two diabetes. The National Sleep

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<v Speaker 1>Foundation offers the following tips to help make sure you

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<v Speaker 1>get enough sleep for your body to function optimally, try

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<v Speaker 1>to aim for seven to nine hours of sleep per night.

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<v Speaker 1>Increase your exercise level, but try not to exercise within

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<v Speaker 1>three hours of your bedtime, and don't ingest caffeine or

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<v Speaker 1>alcohol near your bedtime. Caffeine can keep you awake, and

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<v Speaker 1>alcohol can disrupt the normal stages of your sleep. Today's

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<v Speaker 1>episode was written by Julia Layton and produced by Tyler

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<v Speaker 1>Clang and Tristan McNeil. For more on this and lots

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<v Speaker 1>of other hefty topics, visit our home planet, how Stuff

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<v Speaker 1>works dot com.