Watching Watson, the computer, humiliate our human race on Jeopardy (combined with in-your-face strife and turmoil here and around the world as witnessed on Cable TV) simply reinforces how little we understand about our physiologic selves (1). I’ve mentioned before an interview I did some years back of Craig Venter, the gene genius, where I asked, “What percentage of the knowledge necessary to adequately care for human beings do we currently possess?” To which he replied, “Less than 1%.” (2)
Then last week the CDC made news with a report on sleep, or rather the lack of it.(3) Apparently, we Americans make a habit of not getting enough sleep, and the CDC highlighted how that leads to safety concerns. Specifically, the study suggested that 20% to 25% of our population have “chronic sleep and wakefulness disorders” and that these are “associated with chronic diseases, mental disorders, health-risk behaviors, limitations of daily functioning, injury, and mortality”.
They actually surveyed about 75,000 Americans and determined among other things that over 1/3 of us sleep less than 7 hours a night, 1/2 of us snore, 4 out of 10 have fallen asleep unintentionally during the day in the past month, and 1 in 20 have nodded off while driving at least once in the past month.(3) All of this is important of course, but what interests me more is the mystery of sleep, or more importantly what physiologic insights might be gleaned by a better understanding of sleep.
We’ve known since the 1950’s that there is more going on then meets the eye.(4,5) And we have mountains of brain wave readings (which describe two major types of sleep – REM (rapid eye movement) sleep, characterized by low amplitude, high-frequency EEG rhythms, and non-REM sleep with high amplitude, low frequency rhythms) to prove it. But what’s really happening on a molecular level?
We don’t seem to know. What we do know are a few basics like:
People like to lie down to go to sleep. When they do this, they close their eyes. They don’t hear anything unless it is a loud noise. Their breathing slows down and becomes rhythmic. Sleepers appear relaxed and their muscles at rest, in fact so at rest that they fall over if sitting while sleeping. And yet, unconscious sleepers still adjust their bodies once or twice an hour – probably to maintain circulation and avoid pressure sores. Heart rates slow down and body temperature drops.
And as for the brain, well it enters a world of its own. Do an EEG on a wakeful person and you’ll detect around 20 brain cycles a second. A sleeping person slows down the number of cycles but also varies the number and amplitude of the waves through different types of sleep. Three to five times a night we go in and out of Rapid Eye Movement (REM) sleep during which we dream and exhibit muscle twitching.
All mammals sleep, generally for a protracted period of time (For us, 8 hours is the norm, but horses like 3 hours and bats 20 hours). From an evolutionary standpoint, sleep must have been a serious tradeoff. Downside – you make yourself pretty vulnerable to predators. Upside – studies show we learn better and retain those learnings if we get large packet of sleep each day. (By the way, man’s best friend seems to prefer many short bursts of sleep throughout the day. Birds and reptiles also sleep, but birds dream and reptiles apparently don’t).(6)
As for dreaming, what exactly is going on and for what purpose remains open to debate. Most think its the brain trying to make sense of outbursts of activities, which in real time can incorporate elements from your immediate environment like noises in the room. But it’s nothing like a coma. Yes you’re unconscious, but you can be aroused from sleep – even deep sleep. Noise, shaking even light can be enough to bring you back. While you’re under, something important is going on. It likely effects how information is processed, stored and retrieved. But it impacts more than neural function effecting your endocrine and immune systems as well.(7,8)
Truth is, when you see how little we know about our physiologic and neuroendocrine states for a period that occupies roughly 1/3 of our lives, it’s no wonder Watson beats us hands down. We think like a computer, without imagination, and without passion. What if, in truly understanding sleep, we were to discover how to control our immune response; or deciphered the formulas for ordering and integrating messaging most efficiently; or uncovered how to trigger regeneration; or understood in an elemental way the seeds of human aggression and self-destructive impulses; or figured out non-pharmacologic solutions to pain control; or how to avoid memory loss in Alzheimers disease, or could increase learning capacity by 250%?
Any of those things would have a far greater impact on the future of our human race then falling asleep at the wheel – which isn’t a good idea either.
For Health Commentary, I’m Mike Magee
1. Markoff J. Computer Wins On Jeopardy. New York Times. Feb. 16, 2011. http://www.nytimes.com/2011/02/17/science/17jeopardy-watson.html
2. Personal Communication. Craig Venter. 2005.
3. CDC MMWR. March 4, 2011; 60:8. Unhealthy sleep related behaviors. http://www.cdc.gov/mmwr/
4. Aserinsky, E. & Kleitman, N. Regularly occurring periods of eye motility and concomitant phenomena during sleep. Science 118, 273-274 (1953).
5. Dement, W. C. & Kleitman, N. The relation of eye movements, body motility, and external stimuli to dream content. J. Exp. Psychol. 55, 543-553 (1957).
6. Brain M. How sleep works. Discovery Health. http://health.howstuffworks.com/mental-health/sleep/basics/sleep.htm
7.Boethel CD. Sleep and the endocrine system: new associations to old diseases. Curr.Opin Pulm Med. 2002 Nov;8(6):502-5. http://www.ncbi.nlm.nih.gov/pubmed/12394157
8. Bryant PA. Sick and tired: does sleep have a vital role in the immune system? Nature Reviews Immunology 4, 457-467 (June 2004) | doi:10.1038/nri1369. http://www.nature.com/nri/journal/v4/n6/abs/nri1369.html