Sleeping keeps you out of trouble

sleeeping2.jpgThis is the conclusion reached by leading sleep researcher, Jerry Siegel, after decades of sleep research. In a recent article in the New Scientitst Siegel claims that the effects of sleep deprivation are actually quite small and certainly not enough to offset the potential danger of being asleep (watch out that lion is going to get you!). Evidence from the animal kingdom is surfacing all the time which increases our understanding of sleep. It appears that fur seals, like dolphins, sleep one hemisphere at a time when hunting at sea and experience no REM activity, but once back on land they revert to the more normal sleep patterns of other animals (i.e. both REM and NREM activity and whole brain sleep).Siegel suggests that the purpose of REM sleep may be just to keep the brain stem active. If an animal is sleeping one hemisphere at a time then the brain stem is constantly active. So the purpose of REM sleep is simply to permit periods of NREM sleep. This understanding brings us one step closer to understanding the purpose of sleep. But then we have to ask – why NREM sleep? Siegel agrees that NREM sleep may aid some biological processes (e.g. production of neurotransmitters) but again doubts that it performs any vital functions that can’t be achieved during relaxed wakefulness. If it was vital how can we explain the fact that bullfrogs never sleep and that dolphins perform as well on vigilance tasks after 5 days sleep deprivation.Increasing knowledge of the sleep patterns of different animals suggests that it is ecology rather than biology which explains sleep. Currently only 150 mammals out of a total of 5000+ have been studied and other animal groups have been studied even less. Siegel argues that, on the basis of the current knowledge, the only factor that explains all sleep patterns is that species sleep for as long as they can get away with. The little brown bat sleeps a massive 20 hours per day which shouldn’t happen if sleep was related to size, metabolic rate or danger. The one factor that explains its amount of sleep is the fact that the brown bat eats flies that comes out for a few hours each night. In other words, the bat sleeps because it can and can still survive. Siegel points out that animals are actually safer when asleep; being awake is riskier because you may get injured and may be noticed.Hmmm. But all of this doesn’t explain why I feel so rough after a bad night’s sleep.

0 thoughts on “Sleeping keeps you out of trouble

  1. Adrian Frost says:

    Given the logic of this argument, surely animals at the top end of the food chain (eg elephants or lions) should need sleep less as they have less to fear from predators – yet lions sleep all the time? In a given ecological niche, do prey species sleep more than predators? I dunno – I’m normally the first to defend the evolutionary arguments, but in this case it all feels so counter-intuitive. We are able to suppress so many of our other natural drives, at least temporarily, but the urge to sleep can quickly become distressingly overwhelming, which is why sleep-deprivation is used as a torture technique. And, smarty-pants dolphins aside, it’s clear to all of us that even slight sleep deprivation can significantly affect our emotional and cognitive functioning. There MUST be more to sleep than just staying out of trouble….

  2. Brown Bats and Students, OK…….but what about Goats?

  3. Adrian raises the question about lions – the reason they sleep all the time is because they can. They don’t have to worry about predators so sleeping isn’t life threatening and they eat huge meals and then have time to spare, so they sleep. This fits the view that sleeping is what animals to do when they can.

    I still don’t completely buy it because I feel awful when I haven’t had much sleep so it seems that sleep must be doing something for me.

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