Anecdotally people say that they cannot function as well mentally when they are tired as when they are refreshed from a good sleep, and many research studies support this opinion, with one study showing that staying awake for twenty hours has the same effect on mental agility as having a blood alcohol level of .05.
However, not all researchers agree that mental function is greatly impaired by lack of sleep. In some sleep deprivation studies where the person did not sleep for approximately ten days, there was no marked deterioration in completing mental tasks unless the task was boring.
In fact, at the end of one such study, the sleep-deprived person won a game of pinball and conducted a press conference just before going to sleep. In this case it did not seem that the person’s ability to perform the task was impaired, just that the person had trouble staying awake long enough to do it.
Physical health does not seem to be really dependent on sleep because a person who has his spinal cord severed at the neck cannot instruct his body to sleep, yet the body does not suffer as a result.
The jury is still out
Sleep is a highly organised function, with practically everyone on earth going through the same cycle at the same kind of speed. Presumably there is a very good reason for this because when sleep cycle is disturbed, the person will automatically go more quickly into the stages that have been missed out previously.
The non-REM or Slow Wave Sleep seems to take priority over REM sleep, and so it must be presumed that this is the most important. And stages three and four in particular because these only occur early on in the time taken by sleep.
After not sleeping for several nights in the voluntary studies done on sleep deprivation, the person has one lengthy night’s sleep, and then is back to his usual pattern. He does not need to sleep for an exceptionally long time either to make up for the hours and hours he has missed out on.
In the short term, it would seem then that having some insomnia, or even missing an entire night’s sleep from time to time does no lasting damage to the human body.
The frustration that insomnia causes however is another factor. Stress has been shown to cause real ill health, and so if you cannot change your sleep patterns, at least try to change your attitude towards it.