A Blog Around The Clock

Circadian Rhythm of Alcohol Tolerance

Blogging on Peer-Reviewed Research

i-710d005c8660d36282911838843a792d-ClockWeb logo2.JPGThe original title of this post – “Diurnal rhythm of alcohol metabolism” – was more correct, but less catchy (from February 21, 2006).

Why is breathalyzer a poor method of measuring blood alcohol levels for purposes of DUI tickets? Ed Brayton explains and links to DUI Blog with additional information.

Also, do not forget that every function in the body exhibits a circadian cycle. Likewise, alcohol metabolism:
i-dfbd25c83cb09fc5768d97893530f4db-alcohol circadian.jpg
This is from an old study, from the times when it was OK to recruit some college freshmen to drink alcoholic beverages in the name of science. This is a record of a diurnal rhythm in alcohol clearance, I believe (I cannot find the original paper I swiped this image from a long time ago).

It shows why we can drink more in the evening than at other times of day. You can save some serious money by downing a single shot at dawn, according to this graph.

So, at what time of day/night did the cops stop you to give you a breathalyzer test?


  1. #1 cts
    November 4, 2009

    Reference is a mangled one…

    original ref:

    Wilson R, Newman E and Newman H. 1956. Diurnal Variation in Rate of Alcohol Metabolism. J Appl Physiol 8 556-558.

    figure itself is from a pamphlet:

    Palmer JD 1983. Human Biological Rhythms. Carolina Biological Supply Company, Burlington NC.

  2. #2 Coturnix
    November 26, 2009

    Thank you. You are right.

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