From hydration and digestion to weight loss and body temperature, cold water has attracted plenty of health warnings. But does drinking it actually harm the body, or have popular beliefs outpaced the science?
Water is one of the few beverages that almost everyone agrees the body needs, yet the temperature at which it should be consumed remains surprisingly controversial. In many households, drinking cold water after a meal attracts warnings, while some people are advised to avoid it when they have a cough, a sore throat or even menstrual discomfort. Others believe chilled water helps burn calories, improves physical performance or makes hydration more effective.
The debate is particularly familiar in countries such as Nigeria, where chilled sachet water and bottled water are everyday purchases. A cold drink offers immediate relief, especially during physical activity or after spending time outdoors, but the experience of refreshment does not necessarily tell us what is happening inside the body. The more useful question is whether temperature changes the health benefits of water or introduces risks that consumers should understand.
The scientific evidence points towards a relatively straightforward conclusion. Cold water is generally safe for healthy people, provides the same fundamental hydration benefits as room-temperature water and can offer some advantages during exercise in hot conditions. However, several popular claims about its effects on digestion, respiratory infections and weight loss require closer examination.
Hydration Matters More Than Temperature
The body’s need for water does not depend on whether it comes from a refrigerator, a dispenser or a bottle kept at room temperature. Water supports circulation, temperature regulation, digestion, kidney function and the transportation of nutrients. When the body loses fluid through sweating, urination and breathing, drinking water helps replace that loss, regardless of its temperature.
The distinction becomes important when considering how much people actually drink. Some consumers find room-temperature water easier to consume, while others prefer it chilled, particularly during physical activity. A systematic review examining 14 studies on beverage temperature and exercise found that participants generally preferred cool or cold drinks, and five studies measuring fluid consumption recorded approximately 50 per cent higher intake with cooler beverages than with warmer alternatives.
That finding does not mean everyone should drink ice-cold water or that cold water is inherently more hydrating. The studies focused on exercise, and the increased consumption was partly associated with preference. However, it suggests that when a cooler drink encourages someone to consume more fluid during physical activity, temperature can have a practical advantage.
This matters in hot climates, where people who work outdoors, exercise regularly or spend extended periods in the heat face greater fluid losses through sweating. Drinking enough water remains the priority, but a temperature that makes hydration more appealing can help people maintain their fluid intake. Cold water can also provide some internal cooling during exercise, although the degree of benefit depends on the activity, environmental conditions and individual tolerance.
Does Cold Water Interfere With Digestion?
One of the most persistent beliefs surrounding cold water is that drinking it during or after meals interferes with digestion. The argument often rests on the idea that cold temperatures cause fats to solidify in the stomach, making food harder to digest or slowing the digestive process. It sounds plausible at first, but the claim is not supported by convincing evidence of harm in healthy people.
There is, however, a physiological detail worth examining. A 2020 study involving 11 healthy young men examined how water at different temperatures affected stomach contractions and subsequent food intake. Participants consumed 500 millilitres of water at 2°C, 37°C and 60°C under separate experimental conditions, with researchers observing differences in stomach activity and the amount of food consumed afterwards.
The cold-water trial produced fewer stomach contractions than the hot-water trial and was associated with lower food intake at the subsequent meal. But the experiment was small, involved only young men and examined an immediate response under controlled conditions. It does not establish that cold water damages digestion, causes food to accumulate in the stomach or creates long-term gastrointestinal problems.
The distinction is important because a temporary change in stomach activity is not the same as a medical complication. The digestive system processes food and fluids across a range of temperatures, and there is insufficient evidence to suggest that healthy people need to avoid chilled water after eating. For most consumers, whether water is cold or warm is largely a matter of preference and comfort.
Can Cold Water Cause Colds and Sore Throats?
Another familiar warning is that drinking cold water causes respiratory infections. It is common to hear people associate chilled drinks with coughs, sore throats and the common cold, particularly when someone is already feeling unwell. Yet the common cold is caused by viruses, not by the temperature of the water someone drinks.
A review published in the journal Rhinology examined the relationship between exposure to cold and acute upper respiratory tract infections. Researchers considered several forms of exposure, including breathing cold air, chilling the body’s surface and consuming cold drinks or food. They found no evidence supporting a relationship between the ingestion of cold drinks and the development of upper respiratory tract infections.
This does not mean cold water always feels comfortable when someone is ill. A person with an irritated throat may find chilled drinks uncomfortable, while another may find the cold sensation soothing. Both experiences are possible, and neither establishes that cold water causes or worsens the underlying infection.
In fact, hydration remains important during respiratory illnesses because fever, sweating and reduced fluid intake can contribute to dehydration. The practical consideration is to drink fluids at a temperature that feels comfortable enough to maintain adequate intake. There is no general medical requirement to replace cold water with warm water simply because someone has a cough or cold.
Does Cold Water Help Burn Calories?
The idea that cold water helps with weight loss has also gained attention in wellness discussions. The explanation is based on thermogenesis, the process through which the body uses energy to maintain its internal temperature. When someone drinks chilled water, the body expends a small amount of energy warming that water towards its internal temperature.
The process is real, but its contribution to weight management is frequently exaggerated. A study published in the Journal of Clinical Endocrinology and Metabolism examined the energy expenditure associated with drinking water, including water cooled to 3°C. It found a small increase in energy expenditure after consuming cold water, but the effect was far below what would be required to make chilled water a meaningful weight-loss intervention.
This is where the distinction between a measurable physiological response and a useful health benefit becomes important. Burning a small amount of additional energy does not automatically translate into noticeable weight reduction, particularly when compared with the broader influence of diet, physical activity and overall energy balance. Cold water can support a healthy routine, especially when it replaces sugary drinks, but its temperature should not be marketed as a shortcut to losing weight.
When Cold Water May Not Be Comfortable
Although cold water is generally safe, there are circumstances in which individuals may experience discomfort or require a different approach. One example is achalasia, a relatively uncommon condition in which the oesophagus, the tube that carries food from the mouth to the stomach, has difficulty moving food downwards because the lower oesophageal sphincter does not relax properly.
A clinical study examining oesophageal movement found that cold liquids altered oesophageal contractions in healthy participants and people with swallowing disorders, including those with achalasia. In people with existing swallowing difficulties, temperature-related changes can be relevant to their symptoms. Anyone experiencing persistent difficulty swallowing should seek medical assessment rather than attempting to manage the condition by changing drink temperature alone.
Some people also experience discomfort when consuming extremely cold drinks, including the familiar sudden headache commonly called brain freeze. These reactions are generally temporary and do not mean cold water is dangerous to the wider population. For people who consistently experience discomfort, room-temperature water is a perfectly reasonable alternative.
The more important safety consideration concerns the quality of the water itself. Chilling water does not remove harmful microorganisms or chemical contaminants, and a cold bottle is not automatically a safe bottle. The World Health Organisation’s drinking-water guidelines emphasise the need to manage water safety from its source through treatment, distribution and consumption. Consumers should therefore pay attention to the source, packaging, handling and storage of drinking water, rather than assuming that refrigeration guarantees safety.
The Temperature Debate Has a Simple Answer
The evidence does not support the widespread belief that cold water is inherently unhealthy or that drinking it regularly damages the digestive system. It hydrates the body, supports normal physiological functions and can be particularly useful during physical activity in hot environments. Its contribution to weight loss, meanwhile, is too small to justify treating it as a weight-management strategy.
There are exceptions for people with certain medical conditions or individual sensitivities, but these do not change the broader conclusion. Cold water and room-temperature water both have a place in a healthy hydration routine, and neither needs to be treated as a universal prescription.
Perhaps the most useful distinction is between the temperature of water and the quality of the water being consumed. A properly treated, safely packaged bottle of chilled water can be a perfectly healthy choice, while contaminated water remains unsafe regardless of how cold it feels. For consumers, the priority should be drinking sufficient safe water consistently. Whether it comes with ice, straight from the refrigerator or at room temperature is, for most people, a much smaller health question.
Read more
