By Tanner Flake
It’s easy to look back at our parents’ generation and ask, “How was smoking cigarettes so acceptable?” It’s unbelievable that smoking was so unhealthy yet so pervasive. I believe that our kids will ask our generation a similar question: “How was sleep deprivation so acceptable?” Sleeplessness is a silent epidemic that is rapidly spreading throughout our country.1 This article will summarize why getting eight full hours of sleep is the single best decision you can make for your physical and mental health, cognition, and career.
Physical Health
First, let’s talk about the physical effects of insufficient sleep. It turns out that “beauty sleep” is more than just a silly phrase. A recent experiment took 23 healthy adults and photographed them twice—once after eight hours of sleep and again after an all-nighter. When the photos were randomized and shown to a large group of observers, the subjects in the all-nighter photos were consistently rated as less healthy and less attractive.2 Scientists have also established a link between lack of sleep and obesity. Sleep plays a crucial role in regulating our metabolism, appetite, and ability to exercise. Adults and children who sleep less than six hours a night have a significantly higher likelihood of becoming obese.3
On the scarier side, sleeplessness is tied to the number one and two killers in the US: heart disease and cancer. When we sleep, our heart rate slows, our breathing stabilizes, and our blood pressure drops. This is crucial to cardiovascular health because it gives our heart time to recover from the strain incurred during our waking hours.4
Every year, the entire US population inadvertently performs an experiment displaying the importance of sleep and heart health. This experiment is better known as daylight savings. In the fall, when we gain an hour of sleep, we see a 21% reduction in heart attacks the following day. In the spring, when we lose an hour of sleep, heart attacks increase by a terrifying 24%. Scarier still, this same pattern follows for motor accidents and suicide rates.5
The scientific research supporting a correlation between lack of sleep and cancer is still relatively new, and much still needs to be done; however, current research shows a link between sleep deprivation and the development of several different cancers, including bowel, prostate, and breast cancer.6
On top of that, early research has shown extremely concerning evidence related to natural killer cells and sleep. Natural killer cells are vital to our immune system, acting like little assassins that identify dangerous elements, such as cancerous tumors, and eliminate them. Getting fewer than four hours of sleep causes a 70% drop in natural killer cell activity (see Figure 1).7
The new research has become so compelling that the World Health Organization classified nightshift work as a probable cause of cancer.8 As research continues, the link between sleeplessness and cancer is expected to increase.
Mental Health
Similar to our physical health, insufficient sleep has a profound effect on our mental health. Failure to get enough sleep causes reduced function in the hypothalamus, amygdala, and hormone delivery systems. This reduced brain function leads to erratic mood swings and irrational judgment. Rapid Eye Movement, or “REM,” sleep is a crucial part of our sleep cycle. REM sleep is the only time during our 24-hour day that the brain is devoid of norepinephrine, the anxiety-triggering molecule.9 As we dream, our brain decodes emotional signals. Without adequate REM sleep, we fail to adequately process our emotions and tend to process the world as a more threatening and scarier place.
This is particularly interesting in the case of Post-Traumatic Stress Disorder (PTSD). People who suffer from PTSD often have broken REM sleep. Without this REM sleep, adrenaline doesn’t dissipate from the body the way that it should. REM sleep is like nature’s therapy; the brain can process memories in an environment free of adrenaline and file off the sharp, emotional edges.10 Lack of sleep can severely exacerbate mental health conditions, such as depression, anxiety, ADHD, and PTSD, among many others. Sleep is crucial when it comes to our emotional health.
Cognitive Ability
Healthy sleep is imperative for learning. Sleeping is like our brain’s save button. When we sleep deeply, our brain transfers our short-term memories into long-term storage. Poor sleep quality (even several days after learning a task) impairs our retention and proficiency.11 A lesser-known fact is that we also need adequate sleep before we learn. A study showed that when participants pulled all-nighters and were tasked with memorizing a list of facts the following day, they performed 40% worse than a control group (See Figure 1).12 On a test, that’s the difference between an A+ and a failing grade.
The culprit for this significant performance decrease is likely the hippocampus. The hippocampus is the brain’s information inbox. New information starts in the hippocampus before traveling to the rest of the brain. MRI imagery shows that when one has severely under slept, the hippocampus does not produce any visible activity.14 It seems that lack of sleep shuts it down.
The fact that our sleep quality and memory worsen as we age is well known, but recent studies show that these events might be correlated rather than just co-occurring. Science is starting to illustrate connections between sleep and memory degradation, Alzheimer’s, and dementia.
Career Success
Finally, sufficient sleep can make or break a career. Estimates tell us that poor sleep costs the US economy over $400 billion dollars in lost productivity.15 Impaired cognition—a trademark symptom of poor sleep—slows down one’s ability to be effective at work. Microsleeps are temporary episodes of non-responsiveness or lapses of attention that can last up to 15 seconds.16 They are the body’s way of trying to catch up on missed sleep. Most of us have felt their effects, perhaps describing them as “zoning out” or “daydreaming.” Whatever you call them, their impact on productivity is indisputable.
Your physical health is another important career factor. Feeling unwell makes it difficult to get work done and taking a great deal of time off because of compromised health can put your job in jeopardy. It’s no wonder that forward-thinking companies like Google are buying nap pods to increase worker productivity.
Conclusion
I’ve only scratched the surface of the mountain of research that links lack of sleep to all kinds of negative health outcomes. We must also recognize that sleep has not been adequately researched until relatively recently. Compelling evidence is likely to continue to surface as the volume of research grows.
How can you take advantage of your new sleep knowledge? Strive for eight hours of quality sleep every night. Decide that you will not make the short-term sacrifice of getting to bed too late or waking up too early and then schedule accordingly. If falling/staying asleep is difficult for you, try out the following tips:
- Steer clear of caffeine in the afternoon.
- Establish regularity in your sleep schedule.
- Cool your room down to around 65 degrees Fahrenheit.
- Avoid looking at screens an hour before you go to sleep.
Getting sufficient sleep will change your life by improving your overall health, increasing your learning capacity, and giving you the ability to thrive in your career. Sleeping enough isn’t a waste of time; it’s the best time investment you can make for yourself.
Notes
1. Jagdish Khubchandani and James H. Price. “Short Sleep Duration in Working American Adults, 2010–2018.” Journal of Community Health 45, no. 2 (2019): 219–27. https://link.springer.com/article/10.1007/s10900-019-00731-9.
2. John Axelsson, Tina Sundelin, Michael Ingre, Eus J. W. Van Someren, Andreas Olsson, and Mats Lekander. “Beauty Sleep: Experimental Study on the Perceived Health and Attractiveness of Sleep Deprived People.” BMJ 341, no. dec14 2 (2010): c6614–c6614. https://www.bmj.com/content/341/bmj.c6614.
3. Yili Wu, Long Zhai, and Dongfeng Zhang. “Sleep Duration and Obesity among Adults: A Meta-Analysis of Prospective Studies.” Sleep Medicine 15, no. 12 (2014): 1456–62. https://pubmed.ncbi.nlm.nih.gov/25450058/.
4. “Brain Basics: Understanding Sleep.” National Institute of Neurological Disorders and Stroke. U.S. Department of Health and Human Services. Accessed October 28, 2021. https://catalog.ninds.nih.gov/publications/understanding-sleep-brain-basics.
5. Amneet Sandhu, Milan Seth, and Hitinder S. Gurm. “Daylight Savings Time and Myocardial Infarction.” Open Heart. Archives of Disease in childhood, March 1, 2014. https://openheart.bmj.com/content/1/1/e000019.
6. Matt Walker. “Sleep Is Your Superpower.” TED. Accessed October 28, 2021. https://www.youtube.com/watch?v=5MuIMqhT8DM.
7. M. Irwin, A. Mascovich, JC Gillin, R. Willoughby, J. Pike, TL Smith. “Partial sleep deprivation reduces natural killer cell activity in humans.” Psychosomatic Medicine: November 1994 – Volume 56 – Issue 6 – p 493-498. https://pubmed.ncbi.nlm.nih.gov/7871104/.
8. Eastman CI. “Practical Circadian Interventions for Night Shift Work.” Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, September 2, 2020. https://www.cdc.gov/niosh/nioshtic-2/20045415.html.
9. Matthew Walker. Why We Sleep: The New Science of Sleep and Dreams, 95–96. London, UK: Penguin, 2018.
10. Mark R. Smith, Louis F. Fogg, and Charmane I. Eastman. “Practical Interventions to Promote Circadian Adaptation to Permanent Night Shift Work: Study 4.” Journal of Biological Rhythms 24, no. 2 (2009): 161–72. https://pubmed.ncbi.nlm.nih.gov/19346453/.
11. Björn Rasch and Jan Born. “About Sleep’s Role in Memory.” Physiological Reviews 93, no. 2 (2013): 681–766. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768102/.
12. Seung-Schik Yoo, Peter T. Hu, Ninad Gujar, Ferenc A. Jolesz, and Matthew P. Walker. “A Deficit in the Ability to Form New Human Memories without Sleep.” Nature Neuroscience 10, no. 3 (2007): 385–92. https://www.semanticscholar.org/paper/A-deficit-in-the-ability-to-form-new-human-memories-Yoo-Hu/9b84dc5d19b915b478909201a3c6e40986d5dbc0.
13. Nature Neuroscience. 10. 385-392 (2007). Current Biology. R183-184 (2011)
14. Robbert Havekes and Ted Abel. “The Tired Hippocampus: The Molecular Impact of Sleep Deprivation on Hippocampal Function.” Current Opinion in Neurobiology 44 (2017): 13–19. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5511071/#:~:text=Sleep%20deprivation%20has%20the%20biggest%20impact%20on%20hippocampal%20memory%20consolidation,synaptic%20efficacy%20and%20memory%20storage.
15. Marco Hafner, Martin Stepanek, Jirka Taylor, Wendy Troxel, and Christian Stolk. “Why Sleep Matters — the Economic Costs of Insufficient Sleep: A Cross-Country Comparative Analysis.” 2016. https://pubmed.ncbi.nlm.nih.gov/28983434/.
16. “The Link Between Sleep and Job Performance” Sleep Foundation, September, 2022. https://www.sleepfoundation.org/sleep-hygiene/good-sleep-and-job-performance.
