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Chris6791 said...Jono77 said...Chris6791 said...Underoath said...
Can someone calculate backwards, what his Alcohol content in his blood was if he had 5 hours sleep and weighed 85kg?
I gave it a shot, but my calculation seems too high.
I had it up around 0.29
Weight has a negligible effect on the calculation and sleep none. You need to know what time his last drink was and then what time he did the test and what the reading was. If we guessed at midnight and 10:00am your calculation might be in the ballpark. So his blood alcohol content might not have actually peaked until 3am then it started coming back down. So maybe by 5 or 6 am he's 'sobered up' enough that's he's now just as pissed as he was when the beer stopped flowing at midnight.
The guidelines/rules for BAC calculations are;
1 standard drink = 10grams of alcohol
1 standard drink increases (on average) someone's BAC by 0.02%
The body (on average) processes 1 standard drink out per hour
If he was 0.1% BAC when tested, 5 hours earlier he was 0.2% BAC, if you go by these guidelines issued by drink wise, but there are many variables also to consider.
It doesn't really matter too much when your last drink was, it's more important when your first drink was, the rate of consumption, how much was consumed and what sort of condition your body is in to be able to process the alcohol out of your body.
This is incorrect, the guidelines are intended to keep the average person under the limit (with a bit of leeway in the safe side). This is different to trying to calculate an actual blood alcohol content.
The time of last drink is also extremely relevant when it comes to pissy driving and not blowing over the next morning.. There's a lot of research that shows your blood alcohol level keeps rising for two hours after you stop drinking as it takes that long for it to finish getting from your stomach into your blood. Which takes me back to my original comment/scenario. If your pissed at a wedding and stop drinking you don't actually peak for another two hours (that's why you wake up with the bed spins at 3am
).
After grabbing a roadie for the taxi delaying that that peak to 3am you start coming back down, so by 5 or 6am your blood alcohol level is only now back to where it was when you stumbled out of the wedding reception looking for a taxi.
By 9am you're awake, tired but awake and you poke in a slice of toast, coffee and 6 panadol but in reality you're still pissed as you were when the wedding cake was served 12 hours earlier.
Ever wonder why the booze buses bother doing RBT's first thing in the morning?
What I wrote certainly is not "incorrect". In fact similar to what you have just written but with some numbers to start some calculations. What your saying is fine as well but the last drink does not have as much affect as the quantity you drank, the rate you drink and when you started drinking it.
The last drink is most relivant for roadside RBT. If you have just had a drink within 5 mins of an RBT you could still have alcohol in your mouth causing a very high, inaccurate reading of BAC. The cops then take you to the station, you sit there for 20 mins or so (I forget exactly how long) for the alcohol to clear from your mouth and they retest. By that time the alcohol has gone out of your mouth, into your blood and gives a true reading. Hopefully you haven't been silly and that one drink 5 mins before an RBT was the only one you had.
Yes, you certainly can get tested in the morning and be over the limit but this has more to do with how much you drank the night before and when you started drinking rather than the time of your last drink (unless your last drink was 5 mins ago).
The main challenge for your body is to process the alcohol out, and by Drink Wise guidelines, that is 1 standard drink per hour. The earlier you start drinking, the sooner your body can start processing the alcohol out of your body.
As far as the assumptions of 1 standard drink per hour, and 1 standard drink raises your BAC by 0.02%, yes this is an average, even a conservative average. If there is a need to make this more accurate, an analysis of the particular person is needed eg. Size, body fat, health, liver function, gender, mental state, type of alcohol consumed, food consumed etc.
There are a million scenarios and variables but this is the guidelines to start to understand how alcohol affects our bodies.
