Cold water is generally not bad for you and even has positive benefits for healthy individuals. It is popular as 79% of people in one survey stated they prefer to drink cold water, especially on hot days or after exercise for its feeling of refreshment. Several studies have suggested that it helps boost metabolism rates, assist weight loss, and helps boost low blood pressure.
Cold water does have downsides for those with certain medical conditions that should be taken into consideration. It can lead to weaker immunity for those who already have weaker immune systems and can exacerbate ‘cold stress’ for those in emergency situations struggling to keep their core body temperature up. It can narrow blood vessels, increasing risks for those who suffer from high blood pressure. In some health conditions such as achalasia and sensitivity of teeth, drinking cold water can cause sharp discomfort.
Despite the complications of drinking cold water, societal and cultural values, as well as personal preference, play a big part. Julie Metos who serves as Associate Dean at the College of Health of the University of Utah said that “cold water always tastes better to people.” Dr. Karel Talavera of KU Leuven in Belgium found that cold temperature masks bad tastes which may make drinking cold water more appealing at times.
What Are the Risks and Disadvantages of Drinking Cold Water?
The risks and disadvantages of drinking cold water include thickening of mucus causing respiratory difficulty, headaches, tooth sensitivity, slowing gastric emptying, aggravating achalasia (a rare disease making it difficult for food to pass from the esophagus to the stomach), and causing ‘cold stress’. These are generally rare effects, though tooth sensitivity and headaches are more common for those with related pre-existing conditions.
The following research has confirmed risks of drinking cold water in certain circumstances.
- Nasal mucus thickening. A 1978 study in the journal CHEST published by the American College of Chest Physicians found that nasal mucus thickened after drinking cold water and persisted for more than half an hour.
- Headaches. A 2001 study by P. Mattson of the Department of Neuroscience at the University Hospital in Uppsala Sweden, found that 7.6% of women had a headache after drinking 150ml of ice-cold water.
- Tooth sensitivity. US experts from the McCarl Dental Group in Maryland state that “ some patients report feeling a stabbing pain. Other people experience a dull, lingering discomfort after exposure to hot or cold beverages.”
- Gastric motility. A 2020 study at Japan’s Graduate School of Sport Sciences at Waseda University found that consuming water at 2°C (35.6°F) after 10 minutes reduced gastric contractions to approximately 6 times every 3 minutes whereas those drinking 60°C (140°F) experienced just under 10 contractions every 3 minutes.
- Achalasia (difficulty passing food from esophagus to stomach). Yutang Ren and colleagues at China’s Peking Union Medical College Hospital found that drinking cold water of 2°C (35.6°F) could exacerbate achalasia symptoms such as difficulty swallowing and chest pains.
- Problems during heat exhaustion. Dr. David Schultz of Deaconess Hospital in Evansville, Indiana says that drinking cold water during heat exhaustion can activate the vagus nerves (in the esophagus and stomach which control involuntary activity) resulting in a loss of consciousness.
- Immune system weakening. According to Dr. Pallavi Suyog Uttekar, MD, a clinician in human physiology, drinking cold water can lead to ‘cold stress’ (the inability of the body to warm itself) which among other symptoms can cause narrowing of blood vessels in the throat. While this would likely only occur in extreme circumstances where the body is already struggling to warm itself, if it does occur it can reduce the body’s ability to remove viruses and bacteria, and reduce white blood cells temporarily.
Which Body Parts Can Be Affected by Cold Water?
Drinking cold water can affect the teeth, heart, blood pressure, throat and respiratory system, brain and nervous system, stomach and digestive system, and immune system.
The following research has shown how these body parts are affected by drinking cold water.
- Teeth. Dr. Robert H. DeWitt is a practicing dentist in the Washington Metropolitan Area who says that tooth sensitivity to cold water occurs due to pre-existing conditions from aggressive brushing, gum disease, excessive plaque, or cracked teeth which expose sensitive nerves by removing the tooth’s protective layer.
- Heart. Research at the National Yang-Ming University School of Medicine in Taiwan found that drinking 250ml of ice water significantly lowered heart rates compared to room temperature water. Similarly, a study at Switzerland’s University of Fribourg Department of Medicine found that ingestion of cold water increased energy expenditure over 90 min by 2.9% and reduced the workload to the heart by approximately 4.8 beats per minute.
- Blood pressure. A 2013 study from the Department of Cardiology at China’s Second Affiliated Hospital of Nanchang University found that drinking 4°C (39.2°F) water led to a rise in blood pressure for an average of 22 minutes in healthy students. Satoshi Kubota of the School of Health Sciences at Japan's International University of Health and Welfare found that drinking cold water constricts blood vessels, preventing blood from going to the extremities and raising blood pressure.
- Throat and respiratory system. As per K Saketkhoo et al, drinking water can lead to thicker mucus resulting in respiratory distress
- Throat and respiratory system. A 2012 study by the Chinese Academy of Medical Science found that drinking cold water caused difficulty swallowing, chest pain, achalasia, and other esophageal motility disorders.
- Brain and nervous system. Dr. P. Mattson at the University Hospital in Uppsala Sweden found that drinking cold water can lead to sudden headaches. And Dr. David Schultz of Deaconess Hospital in Evansville, Indiana warns that if one is suffering from heat exhaustion, ice-cold water can trigger a nervous system response that leads to loss of consciousness.
- Stomach and digestive system. Studies have shown that it is possible for cold water to exacerbate the symptoms of achalasia and cause problems with swallowing, as well as exacerbate problems with moving food out of the stomach into the digestive tract. These are not common issues, but those already having problems with such symptoms may find them exacerbated.
- Immune system. In extreme circumstances where a person is already subjected to very cold and wet conditions, drinking cold water can lead to ‘cold stress’ or the inability of the body to warm itself. This in turn can cause a reduction in the body’s immune responses and temporarily lower white blood cell counts.
Why Do My Teeth Hurt When I Drink Cold Water?
Your teeth hurt when you drink cold water if they are already sensitive as a result of other dental problems that have left the nerves exposed. Experts at Crest, a Procter and Gamble company that specializes in dental products, explain that the loss of protective enamel on the teeth causes the canals that lead to nerves to be exposed. These canals are known as dentinal tubules, and when they move due to cold water, they touch the nerves resulting in a dull pain or stabbing feeling.
Robert H. DeWitt, a dentist in Washington DC, says that tooth sensitivity occurs due to aggressive brushing, grinding teeth in your sleep, certain tooth-whitening toothpastes which have abrasive chemicals, gum disease, build-up of bacterial plaque, cracked teeth, or the decay of old fillings. Bacteria in the mouth generates acid and over time breaks down the protective enamel coating of teeth, resulting in sensitivity. Cold water then triggers the nerves and causes pain.
What Are the Benefits of Drinking Cold Water?
The benefits of drinking cold water include a better metabolism rate, boosted weight loss, improved hydration for exercise, and increased alertness. The following research and expert guidance illustrates these points.
- Increased metabolism. A 2003 study by Dr. Michael Boschmann and colleagues at Humboldt-University in Berlin found that drinking water at 22°C (71°F) created 30kJ greater energy expenditure than water ingested at 37°C (98.6°F). This is likely because the body had to work harder to warm the water to body temperature, which boosts metabolism. This effect would presumably be greater at colder water temperatures, though the magnitude of the effect is debated with research from a University of Washington paper finding that only eight additional calories will be burnt per cup of cold water.
- Boosted weight loss. G Dubnov-Raz and colleagues from the Exercise, Nutrition and Lifestyle Clinic at The Edmond and Lily Safra Children's Hospital found that in overweight children, drinking 10 ml/kg of body weight of cold water (4°C/39.2°F) increased resting energy expenditure by 25% for over 40 minutes. Daily consumption of this recommended amount of water for children could result in an energy expenditure equivalent to a weight loss of an additional 1.2 kg per year.
- Improved hydration for exercise. In a 2011 paper published in the Journal of Sports Science and Medicine, Saeed Khamnei of the Islamic Azad University in Tabriz, Iran found that cool 16°C (60.8°F) water is optimum for exercising in the heat and maintaining a low core temperature. A similar study in 2013 in the International Journal of Clinical and Experimental Medicine found the same temperature optimized hydration during exercise by minimizing sweating. And a 2012 study in the Journal of the International Society of Sports Nutrition found that drinking cold water significantly delayed increases in body temperature during exercise such that performance in broad jump and time to exhaustion tests improved by approximately 50%.
- Increased alertness. According to the Foothills Sports Medicine Physical Therapy based in Arizona, cold water helps your body’s adrenaline production making you feel alert without the side effects that caffeinated beverages have. This is also among the benefits of drinking water generally as a part of improved cognitive function.
Does Drinking Cold Water Help You Lose Weight?
Drinking cold water does help you lose weight because it increases your metabolism, helps you feel more satiated, and improves performance during exercise by keeping your core body temperature down and minimizing sweating.
When asking “does drinking cold water burn calories?”, we can point to the 2003 study at Humboldt-University in Berlin which found that drinking lower temperature water led to a greater expenditure of energy and a better metabolism rate. This is likely because the body had to work harder to warm the water to body temperature, thus increasing calorie burn. The magnitude of calories burned is debated, ranging from a mere eight calories per glass of cold water (i.e., almost no impact for weight loss), up to a sufficient effect to lose as much as 1.2 kg per year.
Drinking water helps you feel satiated such that you reduce your calorie intake. Professor Brenda M. Davy and colleagues at the Department of Human Nutrition, Food and Exercise at Virginia Tech university found that drinking 0.5 liters of water 30 minutes before breakfast made participants feel more full and reduced calories consumed during breakfast by 13%. The plot below shows the change in meal size for each of the participants in the Virginia Tech study after ingesting water.
With regards to improvements in exercise performance from drinking cold water, studies in 2011 and 2013 published in the Journal of Sports Science and Medicine and the International Journal of Clinical and Experimental Medicine, respectively, showed that cool 16°C (60.8°F) water is optimum for exercise in the heat and maximizes rehydration while minimizing sweat loss. They argue that cooler water acts as a heat sink to reduce core temperature.
Research by the Heat Research Division of the U.S. Army Research Institute of Environmental Medicine found that cool water at 15°C (59°F) during exercise creates a cyclical drinking pattern, so people tend to hydrate effectively which may result in an improved weight loss regimen.
Is Drinking Cold Water Good for High Blood Pressure?
No, drinking cold water is not good for high blood pressure. Research on the effect of cold water on blood pressure is limited, but studies suggest that it leads to a rise in blood pressure by constricting blood vessels.
Satoshi Kubota et al. of the School of Health Sciences at Japan’s International University of Health and Welfare found that drinking cold water constricts blood vessels, which prevents blood from going to the extremities and raises blood pressure. This induces a transient but significant increase in blood pressure as was seen in a 2013 study by Jianyong Ma et al., from the Department of Cardiology at China’s Second Affiliated Hospital of Nanchang University. They found that drinking 300ml of 4°C (39.2°F) water led to a rise of 3 mmHg in diastolic blood pressure (the denominator reading) for 22 minutes in healthy students.
Diastolic blood pressure is associated with the risk of cardiac events such as heart disease. This diagram shows the increase in blood pressure that occurred after drinking cold and hot water.
According to a 2010 article in the Journal Hypertension, the Red Cross actually suggests people who have donated blood drink water to raise blood pressure in order to prevent fainting. In the original 2007 study by Bruce Newman et al. of the American Red Cross Blood Services, it is suggested that cold or room temperature water would have an equivalent effect in raising the blood pressure of low blood pressure patients.
Who Should Drink Cold Water?
The people who should drink cold water include athletes, overweight children, people with multiple sclerosis, and hypotension (low blood pressure) patients. Or any healthy person who just enjoys cold, refreshing hydration.
Brooke Schantz, RD who works in sports nutrition says that exercising leads to a rise in body temperature which causes fatigue. Drinking cold water reduces the body’s core temperature, allowing performance to be improved. Experts from the US Army, Université des Antilles et de la Guyane, Islamic Azad University, and Performance Nutrition in Phoenix, Arizona all have stated that cold water ranging from slush at -1°C to slightly chilled at 16°C is beneficial during exercise, though the optimum temperature is debated.
For overweight children, cold water can create extra energy expenditure in the body to warm it up which may be sufficient for up to 1.2 kg of weight loss per year according to G Dubnov-Raz and colleagues from The Edmond and Lily Safra Children's Hospital.
This is further supported by a 2003 study on water-induced thermogenesis conducted by researchers at the Medical Faculty of the Charité of Humboldt-University. The study found that drinking water increased metabolic energy expenditure for up to 40 minutes afterward and that this effect was greater if the water was cooler than body temperature. The changes in energy expenditure produced by water intake at each temperature are plotted below for each participant in this study.
Georgia K Chaseling and colleagues at the Thermal Ergonomics Laboratory, Faculty of Health Sciences, University of Sydney, found evidence that cold water ingestion improved exercise tolerance of patients with multiple sclerosis.
Finally, the Red Cross suggests drinking water to raise blood pressure among people who have donated blood to prevent fainting and in hypotensive patients (low blood pressure). This is because it restricts blood vessels and hence leads to an increase in blood pressure.
While it is generally not a problem, for those who wish to be extra careful it may be best to say that babies and the elderly should not drink cold water. This is because their immune systems are weaker and more susceptible to ‘cold stress’ (where the body cannot maintain warmth).
According to India’s Pallavi Suyog Uttekar MD, a board-certified clinician in human physiology, drinking cold water can lead to narrowing of blood vessels in the throat, reduction in the body’s ability to remove viruses and bacteria, and lower the white blood cells temporarily. Drinking cold water is linked with the onset of colds and flu among the babies and elderly. Drinking cold water should be avoided in the case of specific health conditions such as dental sensitivity or achalasia.
Should Pets Drink Cold Water?
Pets should drink cold water as both dogs and cats have shown a preference for it and so it helps to ensure they remain hydrated. No specific amounts are recommended by experts.
The Central Texas Veterinary Specialty & Emergency Hospital (CTVSEH) points out there are rumors that cold water can cause bloating. But Dr. Tina Wismer from the ASPCA’s Animal Poison Control Center says that dogs do not bloat from drinking ice water and that some experts even suggest giving ice water as a treat. On hot days it is a good way to prevent them from overheating.
A 2005 study by the Department of Animal Science at the University of New England found that when given a choice, just over 60% of dogs preferred the coolest water option of 15°C (59°F). Though dogs with lower core temperatures preferred warmer water.
As for cats’ water temperature preferences, Sure Petcare (a cat care product company) states that “Cats sometimes prefer drinking water that is cold, because they might perceive cold water to be fresher.” A 2018 study by the French pet food multinational Royal Canin on the drinking habits of cats concluded that “providing a cat with new options, such as ice cubes or larger blocks of ice (with added “flavor” if required) can encourage it to play and explore, and may also support water intake”.
How Much Cold Water Should You Drink in a Day?
The amount of cold water you should drink a day is whatever portion of your total daily drinking needs that are not met by water of other temperatures. Total baseline water needs are approximately 3.7 liters per day for men and 2.7 liters per day for women according to a study conducted by the US National Academies of Sciences, Engineering, and Medicine.
Recommended water intake for children and young teenagers is lower than for adults, as shown in the chart below, which indicates these amounts in terms of standard beverage cans (330 ml) per day. If you are healthy and not in a place that is very cold, you can drink the entire amount as cold water.
That said, with limited scientific research on the specific topic of how much cold water to drink per day, there are widespread estimates and no strong conclusions. Estimates vary according to the metabolic, dietary, and genetic characteristics of different populations
If one is exercising, water needs are greater and drinking more cold water is advantageous to cool the body down, encourage hydration via feelings of post-exercise refreshment, and reduce sweat. When asking how much water should I drink a day when exercising, a 2013 study in the International Journal of Clinical and Experimental Medicine is helpful. The study found that 6.4 ml of water per kg of body weight taken at a cool 16°C (60.8°F) was optimal for hydration. For a typical 90 kg man, this implies an additional 0.6 liters after exercising on top of the recommended 3.7 liters per day.
As a daily drinking habit, cold water should be avoided by those with weaker immunity such as babies and the elderly, or certain health conditions such as achalasia, sensitive teeth, and high blood pressure.
Which One Is the Best for the Body, Cold Water or Warm Water?
Neither cold water or warm water is inherently best for the body, but each has advantages and disadvantages depending on the context. Both cold water and warm water have been recommended by medical practitioners in different situations, and with no great difference in hydration benefits for most healthy people, personal preference sufficient to induce proper daily water intake is generally the largest factor.
That said, the benefits and disadvantages of cold versus warm or hot water is summarized as follows. Note that both the negatives and positives of one temperature over the other are largely effects that happen at the extremes, and the choice of temperature for healthy people is generally a non-issue beyond personal preference.
- Negatives of warm or hot water. Studies have shown that drinking warm water can lead to inadvertent dehydration by discouraging drinking of sufficient water. This is particularly dangerous during hot weather or vigorous exercise. This is partly cultural as people in many east Asian countries prefer drinking hot water.
- Positives of warm or hot water. Charles Patrick Davis, MD, Ph.D., a Clinical Professor at the University of Texas Health Science Center advises drinking warm water with lemon to protect against kidney stones. Other medical professionals recommend it as helpful against achalasia and say it may help in digestion, circulation, and in the removal of body toxins.
- Negatives of cold water. Drinking cold water may weaken the immune system, especially for babies and the elderly. It can cause pain and discomfort for those with achalasia and sensitive teeth. It can exacerbate ‘cold stress’ for those in situations struggling to keep their core body temperature up. And During heat exhaustion, cold water can activate the vagus nerves (in the esophagus and stomach which control involuntary activity) leading to loss of consciousness.
- Positives of cold water. Drinking cold water maintains hydration during working out and improves human performance during exercise. It reduces pressure on the heart and is helpful in improving the workout efficiency of patients with multiple sclerosis. According to the Foothills Sports Medicine Physical Therapy based in Arizona, cold water helps your body’s adrenaline production which makes you feel alert without the side effects of caffeinated beverages. It can improve blood pressure in hypotensive patients.