HomeVolume 9January 2024 Why wake the witch?

STANISLAS LAJUGIE offers us some very clear research on sleep hygiene, explains why it’s important to get a restful night’s sleep, and definitely convinces us that it’s not a good idea to miss a few hours.

A good night’s sleep or a nightmare day

Sleep is the silent hero. Executive thinking, characterized by nimble mental processes, adaptability, and innovation, depends upon the rejuvenating embrace of sleep.

Yet, sadly, the significance of sleep is often underestimated in our modern education systems and professional lives, both the quantity and quality, though history repeatedly reminds us how sleep deprivation can have extreme effects on our health and mind. In fact, it has been used as a form of torture throughout history.

In 16th century Scotland, at the height of the witch-hunts, women who allegedly practiced witchcraft were captured and put on trial. The hunters needed a confession before a conviction, and thus “waking the witch” was born. Accused women were deprived of sleep for days, after which they would begin to hallucinate and experience psychotic episodes. Their “talk” was recorded as confessions. 

During World War II, the Japanese operated approximately 175 camps where sleep deprivation and other torture methods were used to extract information from both military personnel and civilians, while the British Army had the London Cage, a well-known center for interrogating prisoners of war, which used various harsh techniques, including sleep deprivation. During apartheid, South Africa used sleep deprivation as a torture method until 1994, and the U.S. military allegedly until 2009. 

So, sleep deprivation has a long history as both a means of interrogation and a form of torture. Some groups have reframed it as an “enhanced interrogation technique.” Despite not leaving physical marks, the United Nations recognizes it as a form of torture, defining torture as causing “physical or mental” pain or suffering. Sleep deprivation can lead to hallucinations, psychosis, schizophrenia, and the utterance of irrational statements, making it a concerning and inhumane practice.

While witch-hunts stopped, sleep deprivation has widely spread across the globe.1 The US Centers for Disease Control and Prevention (CDC) describes sleep deprivation as a “public health epidemic,” with an estimated 50 to 70 million adults in the United States with chronic sleep and wakefulness disorders. A recent study in the Netherlands found 27.3% (21.2% of males and 33.2% of females) reporting that they had some type of sleep disorder. Polling based on a validated questionnaire revealed that 32% complained of experiencing general sleep disturbances while 43.2% said they suffered from insufficient sleep. Throughout developed nations, two-thirds of adults fail to attain the recommended seven to eight hours of sleep a night. Sleep disorders afflict approximately 50% of individuals over the age of 55, impairing both the initiation and maintenance of sleep.2 


Every hour counts! 

Why wake the witch and torture yourself? Change of lifestyle and lack of good information on sleep could be the reasons, at a heavy cost! Let’s venture into the repercussions of sleep deprivation that infiltrate all facets of our being. 

1. What is the impact of being deprived of one hour of sleep? 

An annual global experiment called “daylight saving time,” involving 1.5 billion people across 70 nations, provides a stark hint. Each year, on the Monday after clocks spring forward, hospitals see a 24% surge in heart attacks. The reverse occurs in the fall, with heart attacks dropping by 21%, offering the gift of an extra hour’s sleep.3 

There was an experiment in a U.S. school that shifted the start time from 7:25 a.m. to 8:30 a.m., which meant that students enjoyed 43 additional minutes of sleep. Their standardized test scores (SATs) improved by eight to 25%.4

2. What could happen if you sleep six hours a night? 

If the average sleeping time is eight hours (from the seven to nine hours normally advised by the World Health Organization), this is equivalent to a shortfall of two hours. The Surrey Sleep Research Center5 found that 711 genes were disrupted in students who slept for six hours per night for one week, compared with those enjoying a solid eight-and-a-half hours sleep. Among these, half surged into overactivity, including genes linked to chronic inflammation (a precursor to cancer), cellular stress, and factors fostering cardiovascular illnesses. On the flip side, genes fostering stable metabolism and optimal immune responses were stifled.

3. What about five hours of sleep a night? 

Research6 from the University of Chicago unveiled that when healthy young males were limited to five hours of sleep weekly, they experienced a stark reduction in testosterone production and testicle size. This alteration effectively aged them ten to fifteen years in terms of virility. Diminished testosterone not only dampened sexual activity, but also invited fatigue, hampering focus and mental acuity. Women weren’t spared either, as less than six hours sleep a night disrupted hormone production vital for menstruation and fertility, even elevating fertility problems by 80% due to erratic schedules.

4. What about four hours of sleep a night? 

Dr. Michael Irwin from the University of California7 observed that a solitary night of four hours’ sleep eradicated 70% of natural killer cells circulating in the immune system. Imagine the toll after a week, not to mention months or years of sleep deprivation.

5. No sleep at all for a night? 

Randy Gartner is from San Diego, California. He holds the world record of time without sleep from 1964 when he 17 years old, for a period of 11 days 24 minutes! 

Missing 24 hours of sleep can lead to effects similar to a blood alcohol concentration of 0.10 percent, impairing decision-making, judgment, perception, memory, and coordination. Symptoms typically improve after getting some sleep.

In a revealing experiment, participants divided into well-rested and sleep-deprived groups (kept awake all night) were tested on learning capacity. After two nights of recovery sleep, the sleep-deprived group displayed a 40% memory deficit, struggling to absorb new information. Learning-related hippocampal activity was observed in those who slept, while the sleep-deprived exhibited minimal learning engagement. Sleep deprivation had literally frozen their memory processing. Working very late before an exam day does not seem to be a good idea!

Another study involving two groups of young adults—one sleep-deprived and one well-rested—showed that the sleep-deprived participants displayed over 60% amplified emotional reactivity in the amygdala, the fight-or-flight center. Simultaneously, the prefrontal cortex, associated with rationality and decision-making, struggled to temper emotional triggers. The result was heightened irritability and emotional turbulence.


6. 36 hours without sleep?

Bodily functions such as appetite, metabolism, mood, and stress level can be disrupted. Effects include extreme fatigue, hormonal imbalances, decreased motivation, risky decisions, inflexible reasoning, and speech impairments.

7. 48 hours without sleep? 

The immune system becomes compromised, increasing inflammation and decreasing natural killer cell activity.

8. 72 hours without sleep? 

An intense urge to sleep emerges. Cognitive functions like multitasking, memory, and attention severely decline. Emotional stability suffers, causing irritability, depression, anxiety, and difficulty processing emotions in others. Perception becomes distorted, leading to hallucinations and illusions.

9. Longer periods of sleep deprivation? 

Cognitive, emotional, and perceptual functions progressively worsen, ultimately impacting overall well-being.

A prominent contemporary challenge is the delayed onset of sleep due to lengthy work hours, late-night calls, digital distractions, etc., making more and more people affected by sleep diseases. 

So, what constitutes a restful night’s sleep? We’ll find out next time!


To be continued.


1 Chattu, V.J. et al, 2018. The Global Problem of Insufficient Sleep and Its Serious Public Health Implications. Healthcare (Basel) ; https://doi.org/10.3390%2Fhealthcare7010001.

2 Black, D. S. et al., 2015. Mindfulness Meditation and Improvement in Sleep Quality and Daytime Impairment Among Older Adults With Sleep Disturbances: A Randomized Clinical Trial. JAMA Intern Med, Apr;175(4):494-501.

3 Wallker, M., 2017. Why We Sleep: The New Science of Sleep and Dreams. Scribner Books, 

4 Mateika, J.H. et al, 2002. Impact of Sleep on Learning and Behaviors in Adolescents, Teachers College Record, 104(4):704-726.

5 Effects of insufficient sleep on circadian rhythmicity and expression amplitude of the human blood transcriptome. Proc Natl Acad Sci USA, 110(12): E1132-41. doi: 10.1073/pnas.1217154110. Epub 2013 Feb 25.

6 Van Cauter, E. et al, 2007. Impact of sleep and sleep loss on neuroendocrine and metabolic function. Horm Res, 67, Suppl 1:2-9.  doi: 10.1159/000097543. Epub 2007 Feb 15.

7 WIrwin, M.R., 2015. Why Sleep Is Important for Health: A Psychoimmunology Perspective. Annu Rev Psychol, 66:143-172.


Stanislas Lajugie

Stanislas Lajugie

Stanislas is a civil servant of the Foreign Affairs Ministry of France. He has worked in many countries and enjoys making meditation fashionable wherever he goes. He has developed a course on the science of meditation for universities and c... Read More