What does cold water do to your body when you drink it?

December 24, 2025 •

3 min read

According to some research, drinking cold water can lead to a small, temporary increase in metabolic rate as your body expends energy to warm the fluid to its core temperature. This process, known as thermogenesis, is just one of many ways different water temperatures affect the body.

Quick Summary

Drinking cold water offers benefits like improved exercise performance and mild metabolic boosts, but may negatively affect digestion for some individuals. The ideal water temperature for hydration is often based on personal preference and situational needs.

Key Points

Metabolic Boost: Drinking cold water can lead to a small, temporary increase in metabolic rate.
Enhanced Exercise Performance: Drinking cold water during exercise can help lower core body temperature and improve endurance.
Digestion Slowdown: Cold water may temporarily slow digestion for some individuals by constricting blood vessels.
Headache Trigger: Those prone to migraines may experience 'brain freeze' from drinking ice-cold water.
Increased Hydration: Cold water is often found to be more appealing, encouraging greater fluid intake.
Achalasia Aggravation: Cold water can worsen symptoms for individuals with achalasia.
Better Hydration Overall: Staying hydrated consistently is the most important factor, regardless of water temperature.

How Drinking Cold Water Affects Your Body's Systems

When you drink cold water, your body reacts in several distinct ways as it works to regulate its internal systems. The effects are not universally 'good' or 'bad' but vary depending on the context, such as your environment and activity level. From digestion to athletic performance, the temperature of your water can subtly influence how your body functions.

The Metabolic Impact

Drinking cold water may cause a small, temporary increase in your metabolic rate as your body uses energy to warm the water to its core temperature, a process called thermogenesis. While this can burn a few extra calories, the effect is minimal and not a significant weight-loss strategy. Exposure to cold, including drinking cold water, contributes to the body's overall thermogenic response.

Effects on Digestion

Drinking cold water can have mixed effects on digestion. Some traditional beliefs suggest it can slow down the process, and some research indicates it might temporarily constrict blood vessels in the stomach. However, the body quickly warms the water, so any impact is likely minor. For individuals with achalasia, a swallowing disorder, cold water can worsen symptoms.

Impact During Exercise

Drinking cold water during exercise is beneficial, especially in warm conditions. It helps to lower or stabilize core body temperature, preventing overheating and improving endurance. Many find cold water more refreshing during a workout, encouraging better hydration.

The Link to Headaches and Other Conditions

Rapidly consuming cold water can trigger a temporary 'brain freeze' headache, particularly in those prone to migraines. Older research also suggests cold water may thicken nasal mucus, potentially worsening congestion.

Cold Water vs. Warm Water: A Comparison


Feature	Cold Water	Warm Water	Room Temperature Water
Hydration	Often encourages higher intake, especially during exercise.	Absorbed slower by the body.	Absorbed the quickest, making it ideal for rapid rehydration.
Metabolism	Causes a small, temporary increase in metabolic rate as the body expends energy to warm it.	May offer a slight boost to metabolism by increasing body temperature.	No significant effect on metabolism compared to other temperatures.
Digestion	Can temporarily constrict blood vessels, potentially slowing digestion for some.	Can stimulate the digestive system and aid in breaking down food.	Gentle on the digestive system and absorbed efficiently.
Exercise	More effective for cooling the body and improving endurance in the heat.	Less effective for thermoregulation during high-intensity exercise.	A balanced choice, though less effective for cooling than cold water.
Special Conditions	Can trigger headaches in migraine sufferers and worsen symptoms of achalasia.	Can be soothing for sore throats and offer relief for achalasia patients.	A safe and neutral option for most people and conditions.

Making the Best Choice for You

Ultimately, the best water temperature is the one that keeps you consistently hydrated. For most healthy individuals, the effects of cold water are mild and largely beneficial, especially during exercise. If you find that cold water is refreshing and encourages you to drink more, that is likely the best choice for you. However, if you have a condition like achalasia, or are prone to migraines or sinus issues, you may find warm or room temperature water to be more comfortable. For specific advice, it is always recommended to consult a healthcare provider. {Link: Medical News Today https://www.medicalnewstoday.com/articles/325038}

Frequently Asked Questions

For most healthy people, there is no strong scientific evidence that drinking cold water is harmful to digestion. However, some believe it can slow digestion by constricting blood vessels, and individuals with sensitive stomachs may prefer warmer water.

Drinking cold water causes a very slight increase in your metabolism as your body burns calories to warm it. While this effect is negligible on its own, drinking water of any temperature before a meal can help reduce appetite and overall calorie intake.

There is no conclusive scientific evidence that drinking cold water directly causes a sore throat. However, consuming very cold liquids may cause temporary throat discomfort for some, especially those with pre-existing throat sensitivities.

The most important thing for hydration is consistent fluid intake, regardless of temperature. During exercise, cold water can be more palatable and encourage more drinking, but room-temperature water is absorbed most efficiently for rapid rehydration.

This phenomenon, known as 'brain freeze' or a cold-stimulus headache, occurs when a cold substance rapidly cools the palate. This stimulates nerves that refer the pain to the head. Migraine sufferers may be more susceptible.

Yes, drinking cold water is particularly beneficial during exercise, especially in hot conditions. It helps lower core body temperature, delays fatigue, and can improve endurance and overall performance.

Yes, the body's exposure to cold temperatures, including drinking cold water, can cause a temporary vasoconstriction, or narrowing of blood vessels. This is part of the body's thermoregulation process.