Does a few late nights and lack of sleep have that much of an effect on the body?

According to Eve Van Cauter, director of the Sleep, Metabolism and Health Centre at the University of Chicago, “Our body is not wired for sleep deprivation. The human is the only mammal that does this.”  Sleep deprivation effects can be detrimental to the body.

Sleep is an important part of life as you know. It supports many physiological and psychological functions including tissue repair, growth, memory consolidation and learning. A lack of good quality sleep impacts on physiological drivers of energy balance, most importantly appetite, hunger and energy expenditure. Alongside this, sleep deprivation adversely affects the body’s ability to handle glucose (sugar) and may increase the risk of type 2 diabetes.


Shorter sleeping periods are associated with decreased glucose tolerance and increased concentrations of blood cortisol (Our stress hormone), meaning how the body controls the availability of blood glucose to help the tissues of the body and the brain for you to function optimally can be seriously affected.  Research has suggested that long-term sleep restriction, < 6.5 hours per night, may cause a 40% fall in glucose tolerance.

So could not getting enough shut-eye could be interfering with your ability to shed unwanted pounds and stay in shape?

Two key hormones that are effected the most by this are, Ghrelin and Leptin. Ghrelin is your appetite stimulating hormone and signals your brain that it’s time to eat. When you’re sleep-deprived, your body makes more ghrelin. Leptin, on the other hand is your satiety or fullness hormone and cues your brain to put the fork down. When you’re not getting enough sleep, leptin levels plummet.

Dr Van Cauter found in her studies that Leptin levels were 18% lower and Ghrelin levels were 28% higher after participants slept for just 4 hours.

Research from the University of Colorado in Boulder has shown that when study participants didn’t get enough sleep for five days, they consumed more carbohydrates and gained nearly 2 pounds in that time.

So can’t we just catch up on our sleep at the weekend and rebalance things?

According to Dr Van Cauter  “Sleep debt is generally not paid back in full by weekend sleep. I suppose this is kind of like the saying “ An apple a day, keeps the doctor away” – eating 7 apples on Sunday instead of 1 a day just isn’t going to give you the same results!”

sleep deprivation effects_02

This all make logical sense, right?

So let’s flip this on its head and say it’s not about quantity of sleep as such, but more about the quality of sleep!

One of the most interesting aspects of sleep in the western world is what we call a Monophasic sleep pattern, getting all of our sleep in one go. A growing body of evidence from both science and history suggests that the eight-hour sleep pattern may be unnatural.

In 2001, Historian Roger Ekirch of Virginia Tech published a seminal paper, drawn from 16 years of research, revealing a wealth of historical evidence that humans used what is known as a Biphasic sleep pattern, or to sleep in two distinct chunks, which is very common in Mediterranean countries today.

The research describes a first sleep which began about two hours after sunset, followed by a waking period of one or two hours, where people were quite active. They often got up, went to the toilet or smoked tobacco and some even visited neighbours. Most people stayed in bed, read or wrote and then had a second sleep.

Ekirch found that references to the first and second sleep started to disappear during the late 17th Century. This started among the urban upper classes in northern Europe and over the course of the next 200 years filtered down to the rest of Western society.

REM is the truly high quality stage of sleep when a lot of important recovery stuff happens. REM is also when you do most of your memorable dreaming. This stage lasts for a few minutes at a time and makes up 20 to 25 percent of your sleep time if you go through your sleep cycles fully. REM happens about every 90 minutes to two hours with non-REM or brief awakenings making up the in-between times.

So let me leave you with this

As long as you are consistent with the time that you go to sleep and the time you wake up and you are getting quality sleep time, meaning plenty of REM sleep, then how you sleep becomes a personal preference, not a one size fits all approach.

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