So Freshers’ week is over, time to recover. James Riley gives the details of what could be going on in your body right now…
You open your eyes and resist the urge to move your spinning head; one slip here could be fatal. After minutes, which seem like epochs, the parched desert of your mouth forces you to peel your soul from off the pillow and venture to the nearest oasis to quench your irrepressible thirst. At the moment you gain the vertical, you instantly regret those last few shots and that pre-bed nightcap pint of Pinot Noir. As though some invisible giant has swept the floor from beneath your feet, you collapse back onto the bed in a heap. This is the insurmountable hangover: how did it come to be?
Over the coming weeks, alcohol will undoubtedly take its toll on the majority of us, leaving us with that not-so-kind going away present: the hangover. In order to launch a counter-offensive against this loveable foe’s parting gift, it is important to first understand what exactly a hangover is. So, let’s take Sun Tzu’s advice: “If you know the enemy and know yourself, you need not fear the result of a hundred battles … If you know neither the enemy nor yourself, you will succumb in every battle,” and try to emerge from the next battle unscathed.
A hangover is, well, it isn’t a thing per se; rather, it is the accumulative outcome of various biochemical processes which were thrown into disarray as you supped on Satan’s nectar. As the hangover is not greatly understood we could just relinquish our scientific duty and conclude that it is a vorpal curse cast by the devil because you are in his debt; but this wouldn’t aid our quest to alleviate this demoniacal disorder. No, in order to help, we must understand.
Several possible causes were assessed in a 1998 paper, Alcohol Hangover:
Mechanisms and Mediators, by Dr. Robert Swift, M.D. and Dr. Dena Davidson. These causes can be grouped into three categories: direct alcohol effects, alcohol metabolite effects and effects other than alcohol.
Alcohol (ethanol) itself could directly contribute to a hangover in a number of ways. Remember the GABA/glutamate imbalance that contributes to alcohol’s sedative effects? Well, your body tries to counterbalance this neuronal see-saw by increasing glutamate activity; when this excitatory effect continues into the hangover it can lead to sweating, tremors and an increased heart rate. Alcohol can also cause direct irritation of the stomach lining and increase gastric acid production: leading to nausea, abdominal pain and vomiting; and the feeling that you are about to star in the most recent sequel of Alien. Furthermore, by inhibiting anti-diuretic hormone production, alcohol causes dehydration and electrolyte imbalances; mild to moderate dehydration can (quite obviously) cause thirst, lightheadedness and dizziness. Prolonged alcohol ingestion can cause a decrease in glucose production and result in stored glycogen being used, a few days of bingeing can cause alcohol-induced hypoglycaemia. This low blood-sugar condition can lead to weakness, poor mood, and fatigue. Not forgetting that, normally, when you are drinking you should really be sleeping: this leads to the disruption of your bodily (circadian) rhythms and to the production of the stress hormone, cortisol. From these few examples it is obvious how alcohol alone could lead to that horrible hangover, but this is by no means the whole story.
When alcohol (specifically ethanol, the alcohol we drink) is ingested it is broken down, by an alcohol dehydrogenase enzyme, into a metabolite called acetaldehyde, which is then further metabolised into acetate. Acetaldehyde has been shown to be up to 30x more toxic than alcohol and at higher doses can cause some nasty effects: skin flushing, sweating, nausea and vomiting. It also produces a range of free radicals which can cause great damage to the body if they are not moped up by antioxidants such as ascorbic acid (Vitamin C), thiamine (Vitamin B1) and glutathione. However, when you drink alcohol in large amounts your body takes longer to break down the accumulating acetaldehyde, leaving this malevolent molecule around longer to do its damage. Furthermore, the body’s stores of glutathione diminish, leaving the toxic products which acetaldehyde produces around longer to wreak biochemical havoc, and preventing glutathione from going about its regular business of protecting your body from other chemical nasties. So, it’s lucky that acetaldehyde gets metabolised into acetate, right? Well, not quite, one study using rats showed that acetate was a causal factor in the hangover headache experience (although, other factors like dehydration may also contribute). It does just seem like there is no escape.
On top of all this, another clandestine factor may contribute to your hangover. During the fermentation and ageing processes other biologically active chemicals are produced, these are known as congeners. Congeners contribute to the taste, look and smell of all the wonderfully diverse kinds of alcohol which Dionysus blessed us with sampling. Congeners are found in higher concentrations in darker beverages, such as brandy, whiskey and red wine; and in lower concentrations in lightly coloured drinks such as gin and vodka. Various studies have shown hangovers are less severe when these lighter drinks are consumed, backing up the theory that congeners are also a contributor to the hangover. This isn’t really surprising as one common congener, methanol, is broken down by the body into formaldehyde and formic acid! Cheaper brands tend to have higher concentrations of these contemptible congeners and are best avoided. (It seems maternal wisdom prevails.) Congeners may also be the reason why mixing drinks gives such crippling hangovers, as different alcohols have different toxic congeners – so mixing drinks is a good way to get a nice range of different toxins for your body to deal with!
That’s a breakdown of some postulated causes of the alcohol hangover, but what everyone really wants is a cure. In the next article we will explore what science has to tell us about ameliorating the hangover. As the hangover is, presumably, the main reason you will be unable to attend lectures this year, it is probably worth a read.