Feeling overheated, flushed, or feverish is a common symptom reported during a hangover. This sensation of warmth results from temporary disruptions to your body’s process for maintaining a stable internal temperature, known as thermoregulation. Although it can feel like a fever, the elevated temperature perception is usually a side effect of physical and chemical imbalances rather than a significant rise in core body temperature. Understanding these mechanisms explains why your body feels hot the morning after drinking.
How Alcohol Affects Blood Flow and Fluid Balance
The sensation of heat begins with the physical changes alcohol induces in your circulatory system. Alcohol acts as a vasodilator, causing small blood vessels near the skin’s surface to widen. This vasodilation increases blood flow to the skin, which causes visible flushing and the sensation of warmth.
This rush of warm blood to the skin’s surface is the body’s attempt to release heat and cool itself down. However, this mechanism is counterproductive because alcohol is also a diuretic, increasing urine production and leading to dehydration. As the body loses water, overall blood volume decreases, making internal systems less efficient at regulating temperature.
The combined effect of dehydration and vasodilation interferes with the body’s primary cooling method: sweating. Although sweating may increase, the reduced fluid volume means the system is compromised. This leaves you feeling hot and clammy without the relief of efficient evaporative cooling.
The Body’s Inflammatory Response to Alcohol Metabolism
Beyond the physical changes to blood flow, internal chemical processes contribute to the fever-like symptoms. Alcohol metabolism generates a toxic compound called acetaldehyde, which is responsible for many hangover effects. The liver converts alcohol into acetaldehyde, and then rapidly converts that into less harmful acetate.
If acetaldehyde is not cleared quickly enough, its presence triggers a systemic stress response. This involves the release of inflammatory molecules known as cytokines, such as Interleukin-6 (IL-6). These inflammatory biomarkers mimic the symptoms of being sick, including aches and a feeling of being feverish.
Alcohol also interferes with the hypothalamus, the brain region that acts as the body’s central thermostat. This disruption can temporarily alter the core temperature set-point, contributing to the sensation of heat even if the actual core temperature is not significantly elevated. Alcohol affects the autonomic nervous system, leading to heightened stress, which manifests as an increased heart rate and internal feeling of warmth.
Strategies for Cooling Down and Recovery
Addressing the feeling of being hot requires counteracting the underlying fluid imbalance and inflammatory stress. The first step is to rehydrate, using not just plain water but also electrolyte-rich beverages to restore minerals lost through increased urination and sweating. Maintaining adequate fluid levels is necessary to restore blood volume and allow the body’s natural cooling mechanisms to work effectively.
For immediate relief from the sensation of heat, environmental cooling methods can be used safely. Applying a cool compress to the forehead or neck helps lower the perceived skin temperature. A brief, cool shower can also provide relief, though caution should be exercised if you are intoxicated, as alcohol impairs the body’s ability to regulate core temperature in cold environments.
It is helpful to wear light clothing and keep the surrounding environment cool to avoid compounding the body’s struggle with heat dissipation. While most hangover-related heat sensations are temporary, a sustained, high-grade fever is an indication of a more serious issue. If the feeling of heat is accompanied by a measured temperature above 100.4°F (38°C) or is persistent, seeking medical attention is recommended.