How Much Sleep is too Much Sleep?

This is an uncommon question, but a good one nonetheless. It may be hard to believe, because the struggle to get enough sleep is what is keeping most of us awake at night. After all, when was the last time you bumped into a haggard, irritable officemate only to hear them say “I’m having trouble getting too much sleep.” It just doesn’t happen!

The statement “too much sleep” may sound like an oxymoron, but it can happen. Too much sleep can be a sign of health problems, and it’s something you need to watch out for. Just like Goldilocks, you need to get to just the right amount in order to achieve optimal wellness.

In this article, Spire will be exploring the wonderful world of sleep: why you need it, how to get great sleep and how to get just the right amount.

Sleep: Why Does it Exist?

It’s a bit strange, isn’t it? Every night, we fall into several consecutive hours of unconsciousness during which we are unproductive and left vulnerable. Seems like a counterintuitive evolutionary design, but sleep is important. As everyone knows, even a single night of poor sleep can ruin a day’s worth of productivity or enjoyment. A major review conducted at Bradley University by Drs. Pilcher and Huffcutt found that sleep deprived subjects across 143 studies performed, on average, many times worse than those with adequate sleep. In fact, sleep deprived patients performed at the 9th percentile of non-sleep-deprived subjects in all functions tested, which included the full spectrum of motor, cognitive (simple and complex) and mood-related tasks.

A night or two of bad sleep is unpleasant, and may cause you to be irritable, feel fatigued, nauseous, have a lower tolerance for pain and just have an all-around bad day. But chronic lack of sleep gets serious. Consistently failing to get enough sleep yields the following symptoms:

  • Hallucinations
  • Psychosis
  • Long-term memory impairment
  • Lowered cognitive function

On the long term, studies have linked long term sleep deprivation to serious conditions including hypertension, diabetes, and bipolar disorder.

Nonetheless, despite the negative consequences to lack of sleep, scientists do not yet fully understand why we need to sleep. Unlike other necessary and compulsory bodily functions, such as breathing, eating, and eliminating, scientists have been unable to pin down exactly why we need to sleep and why lack of sleep has such serious consequences.

The running theories, as outlined in more detail in this article from Harvard University, include:

Inactivity Theory: Based on the idea of evolution and survival of the fittest, the theory holds that organisms were made to be inactive and sleepy during the nighttime to keep them out of harm’s way when their environments were unsafe (due to being dark). By staying put during the dark parts of a day, beings were protected from predators and physical injury.

Energy Conservation Theory: Nowadays, we have more than enough to eat, but for most human history, lack of calories was a major limiting factor to survival. Those that used their calories efficiently, and could find more faster than others, did not starve and survived to reproduce. During sleep, the human metabolism decreases by 15%, and as such, you save yourself a lot of calories while snoozing. The theory goes that sleep helped conserve calories, and thus was adaptive for our busy ancestors.

Restorative Theory: This theory is one of the most popular and well-known. The idea behind this theory is that sleep serves restorative functions, during which the body repairs damage and rejuvenates itself. There is some evidence of this in animal studies. Animals forced to stay awake will lose all immune function and die in a matter of weeks. There are no studies like this on humans, because such a study would be unethical. But some anecdotal evidence does exist. For example, a Chinese man who stayed up 11 days with no sleep to watch a soccer series in 2012 died after his no-sleep marathon. Many important bodily functions, such as muscle growth, tissue repair, protein and growth hormone synthesis occur mostly, if not exclusively, during sleep. The brain also takes time during sleep to clear a molecule which builds up in the brain during wakefulness called adenosine. Scientists think that this molecule leads to the perception of tiredness and its breakdown is why you feel better when you wake up.

Brain Plasticity Theory: Scientists have found that the brain’s structure and organization changes during sleep. This is the theory behind the critical role that sleep plays in young children and babies, who sleep between 13 to 14 hours a day. The important role sleep plays in reorganizing the brain is also becoming clearer in adults.

These are all good theories, and the truth might be a combination of all four. But the final point is that sleep is important, and even more importantly, that lack of sleep is extremely detrimental. So, that brings us to our next question: how much sleep is enough?

How Much Sleep is Enough?

The amount of sleep you need depends on a few factors, and can be rather individually specific. Some very successful and seemingly healthy individuals seem to require less sleep than the average. For example, Marissa Mayer, who was a CEO of Yahoo! is said to require only between 4 to 6 hours of sleep. But if you are not in this small no-sleep-required elite, the amount of sleep you need will depend more on your age.

Here is a nice chart summarizing the correlation between sleep and age from Mayo Clinic:

Mayo Clinic Sleep Stats

For adults, it seems that between 7 to 9 hours of sleep is the sweet spot. We’ve already established that less than that, your wellness will suff. But what if you are overshooting, by getting 10, 11, 12, or more hours of sleep?

Professor Francesco Cappuccio conducted a study over 10 years looking at how sleep patterns affected the mortality rates of over 10000 subjects. He found the following:

  • Those that slept for five to seven hours or less faced a 1.7 times increased mortality rate compared to those that slept 7 hours a day
  • Those that slept for eight hours or more each night were more than 2 times more likely to die as those that slept 7 hours a day

Does this mean that your 8 to 10 hour a day sleeping habit is leading you to an untimely early death? Not quite.

Dr. Cappucio points out that while there are clearly mechanisms which correlate lack of sleep with decreased health and mortality, there is currently no explanation which would definitely show that oversleep directly causes death. What is more likely, Dr. Cappucio argues, is that oversleep is a symptom of an illness or condition which are in turn linked to higher mortality.

Some illnesses which would cause oversleeping include:

  • Depression
  • Sleep apnea
  • Cancer

Socioeconomic factors can also cause you to oversleep – for example, if you are chronically unemployed, you may find yourself sleeping more than normal.

While oversleeping may not directly cause harm to your wellness, it’s important to recognize oversleep as a sign of deeper problems. If you find yourself unable to get through the day without 9 or more hours of sleep, it might be time to go see a health professional to make sure everything is ok. However, it’s important to remember that sleep more than the average may not be problematic: it might just be who you are programmed to be by your genes. Just as some people genetically need little sleep, you may genetically need a bit more.

How to Get a Great Night’s Sleep

The keys to getting a good’s night sleep every time are good sleep habits and a bedroom environment conducive to sleep. Here are some quick tips to getting started on the optimum sleep routine:

  1. Have a set time to go to sleep – try to get to bed the same time everyday
  2. Unwind for at least 1 hour before shutting down the lights WITHOUT using electronics. Read a physical book, do some yoga, have a hot bath.
  3. Make sure there is no light in your bedroom – investing in light-blocking curtains is a great way to ensure you get a nice, dark room to enjoy your sleep in
  4. Avoid caffeine after noon
  5. Getting some exercise during the day (but not too close to bed) is a great way to get tired out and ready to hit the hay when bedtime arrives.

There are also certain foods that can help you sleep better, as we’ve written about on our blog. Getting good sleep isn’t hard – it’s more a question of discipline and sticking to your routine.

Finally, managing stress is important as well. Going into bed feeling centered and calm is much more conducive to sleeping the right amount than going to bed stressed and distracted. Using Spire can help you achieve this positive state of mind, and ensure that you are going to bed with a very sleep-friendly attitude.

In conclusion, oversleeping might make people think you are lazy or might make you feel a bit guilty, but there isn’t any evidence showing that sleeping too much causes much harm. If you do find yourself sleeping in like it’s the weekend everyday, be sure to check in with a health professional to make sure you’re healthy. Otherwise, just enjoy your extra zzz’s.

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