Sleep XI
"The less you sleep, the more you eat. In addition, you body becomes unable to manage those calories effectively, especially the concentrations of sugar in your blood"
What else needs to be said after the above sentence! If sleeping less contributes to obesity and type 2 diabetes - who in their right minds wouldn't want to sleep more and sleep well?!
Every body has sugar circulating within called blood sugar or glucose, which slowly but surely damage the tissue and organs of your body - eye diseases, nerve diseases, kidney failure, in fact even high blood pressure and heart diseases! But the one we know most about is Type 2 Diabetes.
Again, body being the magician it is, knows how to handle a situation when the glucose shoots up. It releases a hormone called insulin, which instructs the cells of your body to open channels on their surface that deal with the increased glucose flowing in the arteries. Sometimes the cells of the body stop responding to insulin and therefore can not efficiently drain the extra glucose from the blood - taking the body to a hyperglycaemic state, which will eventually lead to a pre-diabetic state and finally leads to Type 2 diabetes.
Researchers have found high levels of glucose in the blood of the people who reported less than 6 hours of sleep routinely, even when adjusted for other causal factors - alcohol, smoking, age, gender, caffeine use etc. However this in itself does not mean less sleep = high glucose !
So scientists conducted experiments with healthy adults who had no existing signs of diabetes or issues with blood sugar. Participants were limited to sleeping 4 hours a night for only 6 nights. By the end of the week, participants were 40% less effective at absorbing a standard dose of glucose, compared to when they were fully rested!
Matthew then goes onto state that if the results were shown to a GP, they would immediately classify the adults as pre-diabetic. So, how does this happen? Does insulin production get affected or do the cells stop responding to the instructions of insulin? Looks the answer is, both ! After 4-5 hours of sleep only for a week, the cells of these individuals had become unresponsive to insulin. Chronic sleep deprivation is now recognized as a major contributor to the escalation of type 2 diabetes throughout first world countries.
The nest set of experiments that were conducted to detect the effect of sleep deprivation on weight gain are maybe my favourite from the whole book. The whole experiment rests on our understanding of two hormones : leptin (responsible for the sense of feeling full/satiated) & ghrelin (triggers the sensation of hunger).
An imbalance of either of the two hormones can trigger increased eating and weight gain is probable.
In an experiment conducted by Dr. Even Van Cauter participants were taken to a hotel and given their own rooms and the whole shebang of a lovely hotel stay, except caffeine. In the first part of the experiment they were given 8.5 hours of sleep opportunity every night for 5 nights. In the second part of the study you're only allowed 4-5 hours of sleep opportunity. In both the studies, you receive the same amount and type of food and your physical exercise is also held constant. Your hunger and food intake are carefully monitored everyday, as are you leptin and ghrelin.
The result? People are far more hungry when sleeping 4-5 hours, despite the same amount of food and exercise as an 8 hour sleep day and this effect showed on the second day of short sleep! Why? because less sleep decreased the levels of leptin and increased the level of ghrelin. So, the "im full" signal was removed and the "I'm hungry" signal was amplified. Therefore your appetite remained unsatisfied.
If this was not mind blowing enough, Dr. Van Cauter added a third dimension to the study. First study of 8 hours and second study of 4-5 hours, same amount of physical exercise, but an open buffet. What do we see? When short sleeping, the very same individuals ate 300 calories more each day compared to when they were routinely getting a full night of sleep.
Ok, last addition to the experiment (!) - on the last day of each experiment , participants were offered an additional food buffet for a 4-hours period - meats, veggies. bread, potatoes, but ALSO cookies, chocolate, chips and pretzels. Participants could each as much in the 4 hours period. What a fun experiment to be a part of you think? I told you it was my favourite!
Here's what we found:
"Despite eating almost 200 calories during the buffet lunch, sleep-deprived participants dove into the snack bar. They consumed an additional calories of snack foods after the full meal, compared to when they were getting plenty of sleep each night. BOOM!
Why again you ask? Because the body during sleep deprivation increases the levels of a chemical called endocannabinoids, which increases your appetite and the desire to snack. This in combination with the decrease in leptin and the increases in ghrelin, leads to one thing only - overeating.
There used to be a theory that said we eat more when we are sleep deprived because we burn extra calories when we stay awake. This has not been rubbished because sleep is an intensely metaboliccally active state for the brain and body - i mean look at all that the body is doing when you are just sleeping. Also, extra calories you eat when you are sleep deprived far outweigh the calories you burn by staying awake. A second also is that when you are sleep deprived you're not in a mood to exercise - further lowering total calorie expenditure.
"Weight gain caused by short sleep is not just a matter of eating more, but also a change in what you binge eat. Cravings for heavy-hitting carb-rich foods, salt snacks, and sweets increased by 30-40% when sleep was reduced by several hours each night. Less affected were protein rich foods, fatty food showing only a 15% increase in preference by the sleepy participants." ~ Matthew Walker
When you are sleep deprived the supervisory prefrontal cortex required for thoughtful judgements and controlled decisions are silenced, in stead the more deep-brain primal structures that drive motivations and desires are amplified. Therefore, high calorie food automatically becomes more desirable when participants are sleep deprived. With a full night's sleep, the communication channel between the deep-brain areas and the higher-order brain that reins in the impulses of the former are controlled using appropriate brakes.
Lastly, sleep also makes your gut happy. Healthy and adequate sleep helps protect and improve the bacterial community known as the microbiome, located in our gut (aka enteric nervous system). Less sleep triggers the SNS which triggers cortisol which cultivates "bad bacteria" to fester through the microbiome. Therefore, insufficient sleep will prevent the meaningful absorption of all food nutrients and cause gastrointestinal problems.
Of course the rise in unhealthy eating habits and a sedentary lifestyle have increased the occurrence of obesity in today's world, but that alone does not account for the numbers we see.
What happens when you're trying to go on a diet and get all fit and healthy with exercise? When given only 5.5 hours hours of sleep opportunity more than 70% of the weight loss comes from lean body mass- muscle. With a full 8 hour sleep, the weight loss comes from fat. The body saves up fat when it is sleep deprived - what you lose then is muscle, which is not the outcome you're looking for!
By all accounts sleeping less will results in you being unhealthy - it will increase appetite, compromise impulse control within the brain, increase food consumption (especially of high calorific foods), decrease feeling of food satisfaction post eating and prevent effective weight loss when dieting.
And with that I am off to sleep for the night.
What else needs to be said after the above sentence! If sleeping less contributes to obesity and type 2 diabetes - who in their right minds wouldn't want to sleep more and sleep well?!
Every body has sugar circulating within called blood sugar or glucose, which slowly but surely damage the tissue and organs of your body - eye diseases, nerve diseases, kidney failure, in fact even high blood pressure and heart diseases! But the one we know most about is Type 2 Diabetes.
Again, body being the magician it is, knows how to handle a situation when the glucose shoots up. It releases a hormone called insulin, which instructs the cells of your body to open channels on their surface that deal with the increased glucose flowing in the arteries. Sometimes the cells of the body stop responding to insulin and therefore can not efficiently drain the extra glucose from the blood - taking the body to a hyperglycaemic state, which will eventually lead to a pre-diabetic state and finally leads to Type 2 diabetes.
Researchers have found high levels of glucose in the blood of the people who reported less than 6 hours of sleep routinely, even when adjusted for other causal factors - alcohol, smoking, age, gender, caffeine use etc. However this in itself does not mean less sleep = high glucose !
So scientists conducted experiments with healthy adults who had no existing signs of diabetes or issues with blood sugar. Participants were limited to sleeping 4 hours a night for only 6 nights. By the end of the week, participants were 40% less effective at absorbing a standard dose of glucose, compared to when they were fully rested!
Matthew then goes onto state that if the results were shown to a GP, they would immediately classify the adults as pre-diabetic. So, how does this happen? Does insulin production get affected or do the cells stop responding to the instructions of insulin? Looks the answer is, both ! After 4-5 hours of sleep only for a week, the cells of these individuals had become unresponsive to insulin. Chronic sleep deprivation is now recognized as a major contributor to the escalation of type 2 diabetes throughout first world countries.
The nest set of experiments that were conducted to detect the effect of sleep deprivation on weight gain are maybe my favourite from the whole book. The whole experiment rests on our understanding of two hormones : leptin (responsible for the sense of feeling full/satiated) & ghrelin (triggers the sensation of hunger).
An imbalance of either of the two hormones can trigger increased eating and weight gain is probable.
In an experiment conducted by Dr. Even Van Cauter participants were taken to a hotel and given their own rooms and the whole shebang of a lovely hotel stay, except caffeine. In the first part of the experiment they were given 8.5 hours of sleep opportunity every night for 5 nights. In the second part of the study you're only allowed 4-5 hours of sleep opportunity. In both the studies, you receive the same amount and type of food and your physical exercise is also held constant. Your hunger and food intake are carefully monitored everyday, as are you leptin and ghrelin.
The result? People are far more hungry when sleeping 4-5 hours, despite the same amount of food and exercise as an 8 hour sleep day and this effect showed on the second day of short sleep! Why? because less sleep decreased the levels of leptin and increased the level of ghrelin. So, the "im full" signal was removed and the "I'm hungry" signal was amplified. Therefore your appetite remained unsatisfied.
If this was not mind blowing enough, Dr. Van Cauter added a third dimension to the study. First study of 8 hours and second study of 4-5 hours, same amount of physical exercise, but an open buffet. What do we see? When short sleeping, the very same individuals ate 300 calories more each day compared to when they were routinely getting a full night of sleep.
Ok, last addition to the experiment (!) - on the last day of each experiment , participants were offered an additional food buffet for a 4-hours period - meats, veggies. bread, potatoes, but ALSO cookies, chocolate, chips and pretzels. Participants could each as much in the 4 hours period. What a fun experiment to be a part of you think? I told you it was my favourite!
Here's what we found:
"Despite eating almost 200 calories during the buffet lunch, sleep-deprived participants dove into the snack bar. They consumed an additional calories of snack foods after the full meal, compared to when they were getting plenty of sleep each night. BOOM!
Why again you ask? Because the body during sleep deprivation increases the levels of a chemical called endocannabinoids, which increases your appetite and the desire to snack. This in combination with the decrease in leptin and the increases in ghrelin, leads to one thing only - overeating.
There used to be a theory that said we eat more when we are sleep deprived because we burn extra calories when we stay awake. This has not been rubbished because sleep is an intensely metaboliccally active state for the brain and body - i mean look at all that the body is doing when you are just sleeping. Also, extra calories you eat when you are sleep deprived far outweigh the calories you burn by staying awake. A second also is that when you are sleep deprived you're not in a mood to exercise - further lowering total calorie expenditure.
"Weight gain caused by short sleep is not just a matter of eating more, but also a change in what you binge eat. Cravings for heavy-hitting carb-rich foods, salt snacks, and sweets increased by 30-40% when sleep was reduced by several hours each night. Less affected were protein rich foods, fatty food showing only a 15% increase in preference by the sleepy participants." ~ Matthew Walker
When you are sleep deprived the supervisory prefrontal cortex required for thoughtful judgements and controlled decisions are silenced, in stead the more deep-brain primal structures that drive motivations and desires are amplified. Therefore, high calorie food automatically becomes more desirable when participants are sleep deprived. With a full night's sleep, the communication channel between the deep-brain areas and the higher-order brain that reins in the impulses of the former are controlled using appropriate brakes.
Lastly, sleep also makes your gut happy. Healthy and adequate sleep helps protect and improve the bacterial community known as the microbiome, located in our gut (aka enteric nervous system). Less sleep triggers the SNS which triggers cortisol which cultivates "bad bacteria" to fester through the microbiome. Therefore, insufficient sleep will prevent the meaningful absorption of all food nutrients and cause gastrointestinal problems.
Of course the rise in unhealthy eating habits and a sedentary lifestyle have increased the occurrence of obesity in today's world, but that alone does not account for the numbers we see.
What happens when you're trying to go on a diet and get all fit and healthy with exercise? When given only 5.5 hours hours of sleep opportunity more than 70% of the weight loss comes from lean body mass- muscle. With a full 8 hour sleep, the weight loss comes from fat. The body saves up fat when it is sleep deprived - what you lose then is muscle, which is not the outcome you're looking for!
By all accounts sleeping less will results in you being unhealthy - it will increase appetite, compromise impulse control within the brain, increase food consumption (especially of high calorific foods), decrease feeling of food satisfaction post eating and prevent effective weight loss when dieting.
And with that I am off to sleep for the night.
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