Oct 4, 2007

On Sleep Deprivation, Mental Exhaustion, and Cognitive Performance

I found myself this week behind schedule on some projects, and this was coupled with a few extra deadlines and periods of lecture preparation. As a result, I ended up staying awake late the past few nights, while skating by on four to five hours of sleep each night.

This, of course, is a recipe for mental fatigue, and by Wednesday afternoon the effects of sleep deprivation were beginning to manifest themselves in my head. I found myself struggling to recall relatively simple words, having difficulty with complex intellectual arguments, and developing that trippy, hallucinatory fog that descends when the brain slows down.

This culminated in an incident in my car after a four-hour class I teach on Wednesday evening. The class went well enough, thanks to my preparation and PowerPoint slides, but I was unable to get the key to turn in my car's ignition, even after I switched positions.

The key in question, you see, belongs to the front door of my house, which is unlikely to serve a dual purpose as the ignition key to my car.

Yet it took me almost a minute to realize my mistake, and I was so tired that I was almost giddy at the surreal scene, too tired to even be frustrated at the situation. It is probably fortuitous that I did not encounter a police officer on the way home, as my impaired mental function might have been perceived as inebriation.

A 2000 study published in the journal Occupational and Environmental Medicine demonstrated that sleep deprivation mirrors alcohol intoxication, and that mental and physical performance on some tests was equivalent or worse than that of a person with a blood alcohol content (BAC) of 0.05%. Moreover, the response speeds of sleep-deprived individuals were up to 50% slower on some tests, while accuracy measures were significantly poorer than at the 0.05% BAC level.

Last night I also went to sleep at a late hour, and as I write this post, my mind is refusing to cooperate with my efforts to write in a semi-literate fashion. I am fortunate that my workload consists of little more than proctoring an exam and taking care of errands today, and that I will have the ability to get at least eight hours worth of sleep tonight. Otherwise, my overworked brain might sink even further into the metaphorical fog, and I am no longer the type of person who enjoys hallucinations.


Mad Jack said...

I put the key in the lock and when I turned it the house started up right away, so I took it for a spin around the block and as luck would have it, when I got back to my yard some miscreant had taken my building spot, and as a result I was forced to park in Ottawa Hills. I don't mind the quiet, but the rates are ruinous.

kooz said...

I understand. I took a new job this year and worked second shift and OT. Typiclly 7pm to 6 or 7 am. Then, My wife would go to work at 8am and I would have the kids all day. I got about 1-3 hours of sleep daily.

I eventually had to quit even though I was making considerably better money than my past job. I had to return to my last job.

I thought I could handle the lack of sleep, but everyone around me noticed a behavioral difference in me pretty quickly and encouraged me to quit.

Barb said...

Maybe, Mike, you have sleep apnea? If you snore and stop breathing --jerky snoring--you have sleep apnea and won't sleep well --but oxygen deprived. Your wife has to analyze and then you get a night in a sleep lab at the hospital --and of course, you wonder how anyone can fall asleep with all these thingies attached to your body designed to measure your sleep phases. But they do assess your need for the machine.

A breathing machine is a panacea --my husband and I both have them --and won't go anywhere without them --they make a HUGE difference

You'd think the discomfort of such an apparatus would keep you awake --but not me. It was such a relief to nod off to dreamland and stay there til dawn.