How does alcohol affect your body?

Friday night, 21:00

After a week of seminars and being nose-deep in your textbooks, you have earned a night out drinking with your friends. The beer cases are stacked, the fridge is full. Let the party begin.

The substance we colloquially call alcohol has the chemical name ethanol. Ethanol dissolves in both water and fat and, as such, can penetrate all cells in our body. Ten minutes after popping the first bottles, the first ethanol molecules reach the blood stream through the stomach wall. After that, the cells in the body also slowly fill up.

After a beer or four, the ethanol reaches the brain and eases any study-related stress. It makes way for a feeling of relaxation. What is actually happening: it dulls everything up there, in your head.

How? Your brain has GABA receptors that, when stimulated by a substance such as alcohol, ensure that the brain cells send fewer signals to one another. You get numbed in a way. This process is enhanced because, at the same time, ethanol blocks the NMDA receptors that ensure brain activity. In short, your brain becomes less active.

‘Alcohol works in the same way as the substances used to anaesthetise you,’ toxicologist Daan Touw from UMCG explains. ‘Due to the blocking of nerve impulses, you get relaxed and are not able to think straight.’

And it makes you feel better. This is the result of our reward system, an area in the brain that is activated when you do something fun, are in love or are having a nice dinner; it makes us glad, happy and cheerful. Alcohol does the same thing, but how it does that is not fully known.

Friday night, 23:59

The Martini Tower strikes midnight. The night is still young. The party continues in town. But hey! Your bike is nowhere to be seen. In front of the house? In the bike stand? Against that tree? Alcohol quickly leads to memory loss, paediatrician Boudien Flapper warns.

‘After a few drinks, you can already see the effect on the brain. You might think you’re still functioning properly, but scans show that, after consuming a small amount of alcohol, parts of your brain are shut down’, Flapper states.

Back to the bike situation. With the help of some friends, your bike is found. It was parked against that tree after all. The party heads for the bar. Once there, it is time to visit the bathroom – it is always the same. Your kidneys are working overtime. Toxicologist Touw: ‘Alcohol suppresses the creation of the antidiuretic hormone (ADH), which in turn slows down the creation of urine.’

The increased production of urine means you can get dehydrated quickly. For every gram of alcohol you consume, you urinate 10 millilitres of additional water. A bottle of beer contains 16.5 grams of alcohol. So if you drank about six bottles of beer by one o’clock, then you would urinate nearly one litre of additional water. That, plus the volume of the beer itself.

After ten beers you are starting to really feel it, but you’d be mad if you think we’d be going home. Adrenalin from your adrenal glands make sure you feel inexhaustible. You decide to go to the club. Sweating profusely, you stumble around the dance floor – you are feeling hot.

It is not due to your surroundings, but because the blood vessels in your skin dilate and you are losing a lot of body heat. You feel hot, but you are actually cooling down. So remember to wear your coat when you go outside for some air; you might get hypothermia.

Saturday morning, 02:00

The DJ is playing Michael Jackson; you think you are the best with your flawless moonwalk. You fail to see the looks of pity. Your dance moves are not what they used to be; your arms and legs no longer do what you think they are doing.

Your cerebellum, in the lower back of your head, has been thoroughly numbed. The cerebellum controls your movement, which is not going so well. Your vestibular system is completely disrupted.

To understand what alcohol does with your sense of balance, we first need to understand the anatomy of this system. The vestibular system can register turning motions and speed changes in multiple directions. It is filled with a fluid. When you move, the fluid stands still for a bit and thus presses against a membrane. This sends a signal to your brain: I am moving.

After a few beers, this membrane is filled with ethanol and becomes lighter. It starts to ‘float’ and gives the brain the fake signal that you are turning. This makes you compensate for movement that is not actually happening; after 15 beers, the moonwalk is turned into a form of controlled stumbling.

Watch this YouTube video of a (very) inebriated man. He is ‘walking’, but is barely moving forward.

Saturday morning, 05:00

Twenty beers and a couple of shots later, you are excessively drunk, but you do not even notice it. When you look closely in the mirror, you can tell that your eyes are shifting back and forth. Your brain, confused by your vestibular system, thinks that you are turning and is sending a torrent of messages to your eyes. These move along with a turning motion that is not there. This phenomenon is called nystagmus.

It is one of the reasons that cute blond girl is looking at you with dismay. Apart from losing control of your bladder, you have also lost all your charm. Overconfident due to the booze, you talk to her, but she cannot understand you. By now, the alcohol has numbed your cerebellum so much that you have even lost control of your tongue.

You feel a wave of nausea rise up. ‘Without vomit, there’s no fun in it!’, a friend to your left shouts at you. Paediatrician Boudien Flapper: ‘Alcohol irritates the stomach wall, which results in an acute stomach infection.’ Add to this the fact that your drunk vestibular system activates the vomit centre in the brain and you are facing the toilet before you know it.

Suddenly, you feel compelled to go home. Without saying goodbye, you jump on your bike and when you get home and in your bed, the world really starts spinning. You lie on your side and the world starts spinning right, because that’s the signal the floating membrane is giving. You turn to your left and the world starts turning left. After all, the membrane is floating to the other side. The entire world seems to be spinning.

The acute stomach infection is rearing its head. You stumble when you get out of bed. The toilet is not far – but just too far away. Oh well, need to clean that up later…

The day after

After a couple of restless hours, you wake up. Why is everything still spinning? Your vestibular system is still under the influence, the fluid has only now been fully filled with alcohol, which makes the membrane heavier and drop. Once again, your brain is given a false signal and the world keeps spinning. The remedy is to crack open another beer; this restores the balance between membrane and fluid.

Your stomach has not recovered from its attack after the binging. The stomach wall is still infected. This can still affect you heavily the day after. The nausea is part of a hangover, according to paediatrician Flapper.

Your head is aching. Toxicologist Touw: ‘Headaches due to drinking are often attributed to dehydration.’ It is not that simple, he says. There are theories that headaches occur due to expansion of the blood vessels in the brain or due to shrinking meninges because of dehydration. ‘The truth is that we’re not really sure’, Touw says.

While you stumble to the toilet, you are breaking out in sweat. Your internal thermostat is failing; it has been sabotaged by the many litres of beer. The boiler seems to have overheated. A painkiller offers some respite thanks to its fever-reducing properties. Also, just empty out the water tap; most of the effects of your hangover are due to dehydration, probably. Probably: ‘We really don’t know all the effects alcohol has on your body’, Flapper says.

Back to bed. While you pull the covers over your body, your head is pounding and your stomach is contracting again, you are certain: ‘I will never, never ever drink again…’

Like Alexander Curly sang a long time ago:

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