What exactly happens when you black out after drinking?

Zhang Chaoran, School of Basic Medical Sciences, Huazhong University of Science and Technology

Yang Shengli, Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology

It is inevitable to drink and chat at the table, one cup after another, sometimes it is because of interest, sometimes it is required by the officialdom, but I wonder if you have ever had such an embarrassing experience: when you wake up the next day, you have no memory of some period of time after drinking at the table the night before. No matter how hard you rack your brains, your memory is like a kite with a broken string, and you can't find it back. This is what people often call "blackouts after drinking". Today, let us analyze the phenomenon of "blackouts" in depth and see what blackouts after drinking are all about.

1. Neuroscience of blackouts after drinking

1. Hippocampus: the “Achilles’ heel” of memory

The hippocampus is the brain's memory library, which categorizes, encodes, and stores our daily experiences, feelings, and information in the brain's memory network. From a neurobiological perspective, neurons in the hippocampus transform newly acquired information into long-term memory through intricate synaptic connections.

However, once too much alcohol enters the brain, it becomes a "troublemaker" - the small molecule fat-soluble structure allows it to quickly break through the blood-brain barrier and directly act on the hippocampus, thereby inhibiting the normal release of key neurotransmitters such as glutamate in the hippocampus. Glutamate, as a "messenger" for signal transmission between neurons, is essential for the consolidation and storage of memory. When alcohol interferes with the normal function of glutamate, it is like cutting off the power supply of the library. Memory cannot be archived normally, and blackouts follow.

2. Neural signal transmission: disrupted “communication network”

The conduction of neural signals in the brain is a highly ordered and complex process, which can be seen as a "courier company". Each neuron is the "transit station" for the courier, which communicates accurately and efficiently through signal handover, thereby supporting various activities such as behavior and memory.

The intervention of alcohol is like a sudden traffic jam, which throws the entire neural signal transmission network into chaos: when alcohol begins to take effect, the neuronal cell membrane becomes diseased, which seriously hinders the generation and transmission of neural signals. In other words, the signal that needs to be transmitted stagnates at the "neuronal transit station", and the memory chain is broken, which ultimately leads to memory loss after drinking.

2. Two Typical Patterns of Fragmentation

1. Complete blackout: “complete blankness” of memory

A complete blackout is an extremely special experience, as if the brain has been "reset" for a period of time, and all memories have been instantly cleared. In this state, no matter how others describe the situation at that time, you have no impression of it at all, as if that period of time had never existed. This situation is usually caused by drinking a lot of alcohol in a short period of time, causing a sharp rise in the alcohol concentration in the blood, causing a comprehensive and strong inhibition of the brain's memory center, and almost completely paralyzing the formation and storage function of memory.

2. Fragmentary fragments: the “fragmented puzzle” of memory

Fragmentary blackouts are relatively common. Memory at this time is like a movie that has been disrupted. Only some scattered fragments and pictures can be recalled, with a lot of blanks and fuzzy areas in between. Although the brain's memory function is not completely lost compared to complete blackouts, some memories cannot be formed or retrieved normally due to the interference of alcohol. In this case, people often need the help of other people's descriptions and memories to piece together the general situation of that night.

3. Trace the root cause: What exactly causes blackouts?

1. Drinking quickly: the brain’s “emergency brake”

Drinking alcohol quickly is one of the common causes of blackouts. When we drink a lot of alcohol in a short period of time, the alcohol will quickly enter the blood circulation system and quickly distribute to various tissues and organs throughout the body, especially the brain. Because the alcohol concentration in the blood rises sharply in a short period of time, the brain has no time to adapt to this rapid change, just like a car suddenly brakes at high speed. Various physiological functions are instantly confused, and memory function is seriously affected, eventually leading to blackouts.

2. Drinking on an empty stomach: double “harm” to the stomach and brain

Drinking on an empty stomach is extremely harmful to the body, especially to the stomach and brain. When there is no food in the stomach, alcohol will directly enter the small intestine and be quickly absorbed into the blood. This will not only cause direct irritation to the gastrointestinal mucosa, causing stomach pain, nausea and other discomfort symptoms, but also cause the alcohol concentration in the blood to rise rapidly in a short period of time, which has a strong stimulating and inhibitory effect on the brain. Due to the lack of food buffering, the impact of alcohol on the brain is more direct and rapid, which is more likely to cause blackouts.

(III) Excessive drinking: the “extreme challenge” of the body’s metabolic capacity

Everyone's alcohol tolerance varies, which mainly depends on the levels of alcohol dehydrogenase and acetaldehyde dehydrogenase in the body. These two enzymes play a key role in the metabolism of alcohol. They can gradually break down alcohol into acetic acid and eventually excrete it from the body. However, when the amount of alcohol consumed exceeds the body's metabolic capacity, alcohol will accumulate in the body. Excessive alcohol will have a toxic effect on the brain's nerve cells, interfere with the normal function of nerve cells, destroy the transmission of nerve signals and the formation mechanism of memory, and then cause blackouts.

4. Scientific drinking guide: How to effectively avoid blackouts

1. Control the speed of drinking: give the brain “buffer time”

The key to avoiding blackouts is to control the speed of drinking. It is recommended to wait 15-30 minutes between each drink to allow the body to gradually adapt to the intake of alcohol. This can provide enough buffer time for the brain to cope with the effects of alcohol normally and reduce the risk of blackouts.

2. Eating before drinking: protecting your stomach and brain

Eating a moderate amount before drinking is an effective way to prevent blackouts. Eating can form a protective film in the stomach, slowing down the absorption of alcohol. Foods rich in carbohydrates, proteins and fats can prolong the time alcohol stays in the stomach, allowing it to enter the small intestine more slowly for absorption, thereby making the blood alcohol concentration rise more slowly and reducing the impact on the brain.

(III) Drinking water in moderation: a tip to speed up alcohol metabolism

Drinking water in moderation can promote urination and help the body excrete alcohol faster. During the drinking process, for every glass of wine you drink, drink an equal amount of water at the same time, which can not only replenish the water lost due to the diuretic effect of alcohol, but also dilute the alcohol concentration in the body and reduce the impact of alcohol on the brain.

In short, knowing your alcohol tolerance is a key step to drinking rationally. Everyone's alcohol tolerance is different, so don't blindly pursue the so-called "not going home until drunk". Drink rationally, don't be stubborn, don't compare, and you can enjoy the fun of drinking while protecting your health.