CAN LACK OF SLEEP REALLY KILL?

Every college student knows the eye-stinging pain of a caffeine-induced all-nighter.  It’s been well documented that prolonged sleep deprivation will lead to lower cognitive and motor function, as well as impaired memory; it might even give you the tired-giggles.  No one has ever definitively shown why sleep is necessary for our survival, and no person has ever had sleep deprivation listed as their cause of death.  As prominent sleep researcher John Allan Hobson states “The only known function of sleep is to cure sleepiness”.  So, can sleep really kill you?

Mouse studies have consistently shown that continued lack of sleep will lead to a 100% chance of death in relatively short order.  To wit, every single mouse that has been subjected to total sleep deprivation has died within 2-3 weeks of the experiment’s start. For obvious reasons, the same studies have not been performed on humans. But given the many animal studies showing this very thing, and countless sleep deprivation studies with humans demonstrating the myriad of health problems associated with a lack of sleep, the general consensus is that a complete lack of sleep for too long will certainly lead to your early demise. However, for reasons that will become clear shortly, “sleep deprivation” isn’t likely to end up being what’s listed as the cause of death.

So how does sleep deprivation kill you?  To answer that, let’s take a closer look at what makes us want to sleep, and what chronic sleep deprivation does to your health.

Maintaining homeostasis is the term used to describe almost every reaction your body is trying to accomplish.  Keeping all its molecules such as proteins, fats, electrolytes, hormones, and even its pH within a specific range.  For example, the body’s normal pH range is 7.35-7.45.  Too far out of this range and your cells begin to die.The same is true of almost every one of the other molecules within the body.

One of the brain structures responsible for maintaining homeostasis via hormone release is your hypothalamus.  The hypothalamus controls things like body temperature, hunger, thirst, fatigue, emotions, growth, salt and water balance, weight and appetite, and the circadian rhythm involved with sleep.

There are quite a few components working together that make you want to sleep and wake up.  They normally revolve around 24-hour cycles known as circadian rhythms.

One factor that makes you want to sleep is the presence of Adenosine which inhibits any factor causing wakefulness. The body also reacts to cycles of light and darkness to regulate sleep.

For the average person, getting only 6 hours of sleep per night for 1 week has been shown to change 711 of your genes.  Those changes could be at the core of why sleep deprivation is so damaging.

Cardiovascularly, sleep deprivation has been associated with high blood pressure, atherosclerosis (too much cholesterol in your arteries), heart failure and heart attack.  A 2011 study from Warwick Medical School found that less than 6 hours of sleep per night gives you a 48% greater chance of developing or dying from heart disease.  If heart problems don’t worry you, your risk of stroke will quadruple if you’re overweight and get less than 6 hours of sleep per night, compared to people who get 7-8 hours of sleep and are of healthy weight.

Why bring weight into it?

After just 1 night of interrupted sleep, people tend to eat more and choose high-calorie, high-carb foods, the culprit being those abnormal hormones again.  When you don’t get enough sleep, your body releases more of the hormone that makes you feel hungry (ghrelin), and releases less of the hormone that makes you feel full (leptin)

Sleep deprivation also results in higher blood sugar levels, increasing your risk of developing type 2 diabetes. This is because a lack of zzz’s decreases your insulin sensitivity- basically, you’re eating more, and the body’s ability to use those sugars goes down because it won’t respond to the insulin that’s released.

If heart attacks, obesity, strokes, and diabetes aren’t bad enough potential byproducts of lack of sleep, how about mental health problems?

Overall brain health is also affected by a lack of sleep. The body normally gets rid of waste by the lymphatic system.  In a nutshell, what is being called the glymphatic system clears the brain of waste products that increase when you’re awake.

Brain cells actually reduce in size while sleeping, allowing for cerebrospinal fluid to better flow between neurons, eliminating more waste.  Studies on the subject show beta-amyloids (plaques found between neurons in Alzheimer’s disease) are eliminated twice as fast while sleeping then when awake.

Those more critical of semantics might argue that it’s not the sleep deprivation that kills you, but rather the reactions by the body to the deprivation. In the end, does it matter? Either way, bad sleep habits will undoubtedly prevent the body from being able to maintain homeostasis in many essential functions, helping to prove workaholics right- they’ll sleep when they’re dead.