I want to know, is there any standard protocol to classify sleep deprivation, as mention above ?
There are a couple of semi-quantitative ways to do this. First, you might use the levels specified in the SAFTE/FAST model (http://en.wikipedia.org/wiki/Fatigue_Avoidance_Scheduling_Tool). At 90% cognitive effectiveness, you have been awake 16 hours and are ready for a normal night of sleep. This might be called mild fatigue (aka mild sleep deprivation). At about 70 to 76% cognitive effectiveness you have a blood alcohol content (BAC) equivalency of 0.08 to 0.05%, respectively. This might be called moderate fatigue. At about 65%, you have missed an entire night of sleep and it may become difficult to remain awake on the job that afternoon and evening. This might be called severe fatigue.
Second, you might use the five fatigue classifiers similar to those suggested originally in the NTSB fatigue class.:
More than 17 hours since the preceding major sleep period.
Less than 7 or 8 hours of sleep in the preceding 24 hours.
Cumulative sleep debt greater than 8 or 10 hours.
Jet lag or shift lag greater than 3 hours.
Time of night between midnight and dawn.
If one of these is true, I might call it mild fatigue. If two or three are true, then moderate fatigue. If four or five, then severe fatigue.
Time of night between midnight and dawn.
thanks sir, but can we classify sleep deprivation on the number of hours of lack of sleep ?. is there any authenticated nominal scale to define these, and how we can differentiate between sleep deprivation and sleep restriction.
I don't think that there is a validated scale for sleep deprivation. I have suggested a method for estimating the pre-accident level of sleep deprivation in chapter 8 of my ebook, Anatomy of A Fatigue-Related Accident (https://www.smashwords.com/books/search?query=anatomy+fatigue). It is:
"A simplistic method for calculating cumulative sleep debt follows. Work backward in 24-hour segments from the time of the incident to the last time that the individual was fully “caught up” on their sleep. For example, they were caught up because they had slept at least eight hours per night for a week or so. Alternatively, work backward as far into the past as possible. For each 24-hour period, estimate the hours of sleep acquired. Subtract each estimate from eight hours (or, substitute another, known minimum sleep time for an individual, such as seven-and-a-half hours). When the person acquired too few hours of sleep, the difference will be positive. When they have acquired “recovery” sleep, the person will have slept more than eight hours and the difference will be negative. If the difference is negative, multiply it by two because we make up sleep faster than we lose it. Add all of the positive and negative values together to get the cumulative sleep debt.”
An example follows in the ebook. A version of this method can also be used on a day-to-day and week-by week basis by a worker. I suggested doing this in my "21 Tips" book (http://21bookseries.com/store/products/21-tips-for-beating-fatigue-and-improving-your-health-happiness-and-safety/). It is:
"Estimating your sleep debt is pretty easy. Record the total number of hours that you sleep each day during a vacation. This includes the major nighttime sleep period plus any daytime naps. Most likely, you will experience “recovery sleep” during the first several days of the vacation. That is, you will be repaying the sleep debt that you carried into the beginning of the vacation.
Eventually, you will settle into a pattern of sleeping a relatively stable number of hours per 24 hours. The average of these relatively stable amounts is your natural sleep need. Then, when facing night work demands, keep track of how many hours less than this number you sleep per 24 hours. This difference is your sleep debt, and it adds up across days.
The rate at which you can repay this debt varies from person to person: you can repay it with recovery sleep at a ratio of about two to one to about four to one. That is, if you have a sleep debt of six hours, you may repay it adequately with one-and-a-half to three hours of extra sleep that is of good quality and occurs during the nighttime. By "extra," I mean in addition to your known sleep need."
There is no such specific scale existing to classify sleep deprivation as mild, moderate and severe, however it can be classified as Acute or Chronic Sleep Deprivation
Note that acute sleep deprivation and cumulative sleep restriction are different in terms of recovery patterns.
It is the quality of sleep which is important not the hours of sleep . The status of day time wakefull ness and alertness which is important not the hours of sleep in night
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