What Causes a Hangover, and How Alcohol Causes Dehydration?

After a night of excessive alcohol consumption, the misery of a hangover is all too familiar. Hangovers are caused by various factors, primarily the direct effects of alcohol on the body, including dehydration. Other symptoms can result from alcohol withdrawal, specific chemicals produced when consuming alcohol, behaviors associated with drinking, and personal characteristics.

Direct Effects of Alcohol on Hangover Symptoms

Alcohol directly contributes to hangover symptoms in several ways:

1. Dehydration and Electrolyte Imbalance: Consuming alcohol increases urine production, sweating, vomiting, and diarrhea, leading to dehydration. This causes common hangover symptoms like thirst, weakness, dry mouth and nose, dizziness, and lightheadedness.

2. Gastrointestinal Disturbances: Excessive alcohol consumption can irritate the stomach and intestines, leading to gastritis and delayed stomach emptying. Chemicals secreted by the pancreas and intestines can cause abdominal pain, nausea, and vomiting.

3. Low Blood Sugar: Alcohol can inhibit glucose production and deplete glucose reserves stored in the liver. As glucose is the brain's primary energy source, low blood sugar contributes to fatigue, weakness, and mood changes associated with hangovers.

4. Disruption of Sleep and Other Biological Rhythms: Alcohol-induced sleep is often shorter and of lower quality than usual, causing fatigue. Additionally, alcohol disrupts the body's daily temperature rhythm, the nighttime secretion of growth hormones, and the release of cortisol, resulting in symptoms similar to jet lag.

5. Headache: Alcohol intoxication causes blood vessels to widen (vasodilation), leading to headaches. Consuming alcohol also affects the production of histamine, serotonin, and prostaglandins—hormones thought to contribute to headaches.

6. Alcohol Withdrawal: Heavy drinking depresses the central nervous system. When alcohol is withdrawn, the central nervous system can go into an unbalanced hyperactivity state, causing tremors and rapid heart rate associated with hangovers. Many hangover symptoms overlap with those of alcohol withdrawal syndrome.

7. Effects of Alcohol Metabolites: The enzymes alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) break down alcohol molecules in the body so they can be eliminated. During this process, a toxic intermediate metabolite called acetaldehyde is produced. Although acetaldehyde is no longer present once the blood alcohol level reaches zero, its toxic effects can persist into the hangover period.

Other Factors Contributing to Hangovers

Apart from alcohol itself, several other factors can contribute to a hangover, including:

1. Congeners: Most alcoholic beverages contain congeners, which are chemicals that contribute to their taste, smell, and appearance. These compounds can exacerbate hangover symptoms. Clear liquors like gin and vodka contain fewer congeners and cause fewer hangover effects than dark liquors such as whiskey, brandy, and red wine.

2. Use of Other Drugs: People who drink heavily often use other drugs and smoke cigarettes. These substances can cause their own set of hangover-like symptoms. While marijuana, cocaine, and other drugs can contribute to situations that foster excessive alcohol intake, their exact effects on alcohol hangovers are not fully understood.

3. Personal Influences: Certain personality traits, such as shyness, can intensify hangover feelings and create a sense of "hangxiety." Negative life events, feelings of guilt, and the risk of alcoholism often produce acute hangover symptoms.

4. Family History: People with a family history of alcoholism tend to experience worse hangovers than those without a family history. However, this might be related to the fact that people with a family history of alcoholism generally consume more alcohol.

How to Treat a Hangover

To relieve hangover symptoms, you can try the following strategies:

1. Rehydrate: Replenish lost fluids and electrolytes by drinking water, bouillon, or electrolyte beverages like Gatorade and Pedialyte.

2. Take Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): NSAIDs like aspirin or ibuprofen can help relieve headaches and body aches. However, avoid NSAIDs if you have stomach pain or ulcers, as they can worsen these symptoms.

3. Eat Healthy Food: Consuming a meal high in fiber and healthy carbs can help restore blood sugar levels.

4. Take Vitamin B3 (Niacin) or Zinc: Recent research suggests that vitamin B3 (niacin) or zinc supplements may be effective in reducing hangover symptoms.

5. Avoid Acetaminophen (Tylenol): Do not take acetaminophen for a hangover or after drinking alcohol, as the combination of this medication and alcohol can damage your liver.

When to Seek Medical Attention

Hangovers themselves are not life-threatening and will subside without medical intervention. However, if you experience frequent hangovers interfering with your daily life, consult a doctor to evaluate whether you have an underlying condition like alcoholism. Help and effective treatments are available.

Conclusion

Hangover symptoms result from various factors, primarily dehydration and the toxic effects of alcohol on the body. While rehydrating with water or sports drinks can quickly relieve dehydration, the toxic effects of alcohol on your central nervous and gastrointestinal systems can only be reversed with time.