Abstract: http://www.pnas.org/content/early/2014/07/02/1402663111
New research has found that the time of day and sleep deprivation have a significant effect on our metabolism, which means that when a blood sample is collected for certain tests could be important.
Researchers from the University of Surrey and The Institute of Cancer Research, London, investigated the links between sleep deprivation, body clock disruption and metabolism, and discovered a clear variation in metabolism according to the time of day.
Healthy male volunteers were put in an environment where light, sleep, meals and posture were controlled. Researchers collected blood samples every two hours to show how metabolic biomarkers change during the day. For the first 24 hours, the participants experienced a normal wake/sleep cycle. This was followed by 24 hours of wakefulness, to investigate the effect of sleep deprivation on metabolic rhythms. The results showed that metabolic processes are significantly increased during sleep deprivation. 27 metabolites, including serotonin, were found at higher levels in periods of sleep deprivation compared to levels during sleep.
Lead author Professor Debra Skene from the University of Surrey, said: "Our results show that if we want to develop a diagnostic test for a disease, it is imperative to take the time of day when taking blood samples into account, since this has a significant effect on metabolism. This is also key for administering medicines and determining when they will be at their most effective. Of course, this will have to be considered on a case-by-case basis, since many people such as shift workers will have a different sleep/wake cycle and timings will need to be adapted to their body clocks."
(Score: 1) by wantkitteh on Wednesday July 09 2014, @02:42PM
I have DSPS [google.co.uk], does this mean my hospital appointments have to be moved to 4am from now on?
(Score: 3, Informative) by VLM on Wednesday July 09 2014, @02:49PM
There's some issues with the summary. Daily variation is really old news. One of my kids, admittedly not that old, had some neurotransmitter tests vaguely like this done with samples taken all day long. Which turned out to pretty much be meaningless but whatever.
Anyway what I got out of the abstract is not that they discovered cycles, but they specifically verified the previously known cycles on a normal sleep pattern day and then kept the subjects awake for 24 hours to see how the pattern decayed if at all over awakefullness (the "Q" factor of the oscillator, which apparently isn't very high in biological specimens compared to electronic oscillators)
So this would have "not much" impact on regular work on regular people but maybe someone really sick in the ER whos been awake 72 hours straight or whatever would have some substantial weirdness.
It also has some scientific proof that keeping a doc awake on call for 36 hours might not be medically advisable for the doc's patients, if you can measure the collapse in the poor bastards neurotransmitter levels. Yeah yeah I know you're not a real doc unless you undergo hazing, but how many patients have to die for that good clean fun tradition? Why can't docs do their noob hazing via something safer for the patients like alcohol poisoning, paddling, and unprotected sex (with other docs, not patients, presumably) like frat boys?
(Score: 5, Interesting) by Dunbal on Wednesday July 09 2014, @06:59PM
"It also has some scientific proof that keeping a doc awake on call for 36 hours might not be medically advisable for the doc's patients, if you can measure the collapse in the poor bastards neurotransmitter levels."
Suffice it to say I had 2 car accidents in my intern year. I don't consider it a coincidence since I haven't had an accident since (over 10 years ago) nor did I have an accident 10 year previously. Call is a great example. In the country where I got my medical degree (somewhere in Latin America) call was every 4th day. You'd report for duty at 5am for your regular shift, checking on the patients under your care. Then you'd do the rounds with the attendings, the residents and students. After that you'd mostly do paperwork, chase up biopsy and lab reports, do procedures, assist in surgery if you were in your surgery internship, etc. THEN you might have a class, a quiz or a test, or a department meeting. Then at 3pm you'd head down to the ER, strip down into your scrubs (ahh working in PJs - best profession ever), and do whatever needed to be done in the ER until 5am the next morning.
Usually late in the wee hours when the amount of new patients slacked off we'd split the remaining hours between us and half of us would go sleep while the rest stayed awake for a few hours then we'd swap. On busy nights that wouldn't happen and no one would sleep. And THEN at 5am you'd have a quick shower, head upstairs and get your ward ready for rounds again and start a brand new day. Standing in an operating room for 4 hours wearing a protective lead apron after having been awake 30 hours is not fun... And finally at 3pm you got to go home if you were lucky, if all your work was done. I'd get home by 5pm, fall asleep immediately and wake up at 4am the next day. Now repeat this every 4th day. For at least a year.
Yes, sleep deprivation can be draining on stamina, neurotransmitters, patience, and anything else a doctor might possess. However something else happens too. It's probably the same phenomenon that happens to soldiers on the battlefield. Some things become so deeply ingrained that they become part of somatic memory. You really switch to autopilot and your body learns to take the right action at the right time almost reflexively. Medicine is far simpler than most people think it is. Yeah there's so much you need to learn and understand so that you can say you know what you are doing - but the "correct" answer to stabilize a patient who is suddenly unstable is pretty much always the same. When you've seen your 200th heart attack you know what to do without using any neurotransmitters at all. When you've seen your 500th you can almost tell it's happening before the patient realizes. Even the complications become routine. But that only happens if you put the hours in. And you never forget the times it happens at 4am. The world becomes surreal, almost like a dream. But you do the right thing because you have done it so often.
I'd say that call is more than just a type of "hazing", and although it is rough on the physician undergoing it it also brands medicine into the core of your being. I don't think it's unnecessary or particularly dangerous (provided exhausted interns and residents aren't left without any supervision at all). It's a way of really learning deep down inside the actions we need to take at a moment's notice that can save a life.
(Score: 2) by egcagrac0 on Wednesday July 09 2014, @06:55PM
Anyone who has interacted with someone who has been awake for 24+ hours should be readily able to deduce that metabolic and neurotransmitter levels are atypical in this case.
But, hooray science, for measuring, not just guessing.