Many people around the world start their day with a glass of warm or hot water every morning. You see it in some social media feeds: people touting the benefits of drinking warm water, especially in the morning, as an aid in everything from weight loss to removing toxins.

But are these statements true? First, let’s look at why water is so critical to your health. We spoke with Mary Lou Perry, MS, RDN, CDCES, dietitian and nutrition expert at UVA Health, about water and your health.

How much water is in your body?

On average, water makes up about 60% of the human body, although the number varies depending on age, gender and other factors.

Your lungs are made up of about 83% water. Your bones are also 31%.

Facts about water and your health

Water is essential for your body to function. Perry says it regulates temperature and balances body chemicals, such as electrolytes. It is necessary for digestion and waste elimination. It supports your joints and helps cushion your bones, allowing you to move.

If you don’t drink enough water, you can become dehydrated, which means you’re taking in less fluid than your body can get rid of. Usually, we think of fluid elimination in terms of peeing (urinating) and sweating (sweating), but diarrhea and vomiting are also major causes of dehydration.

We lose water all the time, through normal sweating, peeing and even breathing. Exercise speeds up this process, as does living in a hot climate or at high altitude.

Dehydration

While everyone should stay well hydrated, the consequences of dehydration are potentially worse for infants, children and older adults. “Regardless of temperature, water is always best for hydration,” notes Perry. Symptoms of mild dehydration include:

• Sensation of thirst
• Dry mouth,
• Feeling tired
• Heachache
• Darker urine than usual

Reversing mild dehydration is simple:

• Drink more water
• Eat fruits and vegetables
• Reduce physical activity in hot weather

The impact of severe dehydration

Severe dehydration is on a completely different level. It can cause serious damage to health, also causing:

• Heat stroke
• Rapid heartbeat
• Confusion
• Fainting
• Shock

It can also lead to coma or be life-threatening if not addressed. If any of these symptoms appear, consult a doctor immediately. One of the first treatments you will receive will be fluids to replenish your body.

But don’t let it come to that. Make sure you and your family members drink enough water. There are different minimums based on age, gender, where you live, etc. Do your research online and follow the advice of trusted sources. Perry suggests checking USDA.gov.

Myths and facts about hot water

Now let’s look at some of the claims about warm and hot water, starting with the least controversial ones.

Myth or fact? Drinking warm water is better than cold water in the morning

For many people, drinking warm or hot water when they wake up is a pleasant way to start the day. There’s a good reason for this. Most people, whether they sleep like a baby or toss and turn all night, wake up slightly dehydrated.

While hot or cold water would be fine in this case, some people find that rehydrating with warm water is easier on an empty stomach.

Verdict: It depends on your body and your preferences. “There is limited scientific evidence comparing hot water to cold water,” Perry says. If you try it, the belly-friendly quality of hot water might work better for you.

Myth or fact? Hot water detoxifies your body

Next up is the claim that drinking warm water “eliminates toxins.” This is false on its face. This is because water does not eliminate toxins. Your liver breaks down toxins and your kidneys filter waste in the form of pee.

Now, it’s true that good hydration helps these organs work at their best (and this is still very important), but that’s all. The water temperature here has no influence.

Verdict: Definitely a myth.

Myth or fact? Warm water aids digestion

Another popular belief is that warm water helps digest food more effectively. This idea originates in some practices of traditional Eastern medicine. Today’s science neither fully confirms nor rejects these views.

Certainly not drinking enough water can lead to constipation, but the temperature of the water doesn’t really matter. Some studies suggest that warm liquids, including water, can help relax the digestive tract, which can make bowel movements easier in some people. But Perry points out that’s different than suggesting that digestion improves with hot water.

Verdict: Again, hydration is the key, not temperature.

Myth or fact? Warm water cures sore throat

Does hot water cure a sore throat? It’s actually a trick question. Warm water helps with sore throat symptoms, but does nothing to fight the causes of sore throat, such as viruses and bacteria.

It can temporarily ease burning and itching sensations and make swallowing easier, which is huge if you suffer from severe throat pain. Broth and hot tea, both containing hot water, are also helpful.

But to address the root cause of your sore throat, your doctor will order time and/or antibiotics.

Verdict: Myth, if you’re hoping it can cure your sore throat. But warm water can relieve some of the pain caused by a sore throat.

Myth or fact? Hot water helps you lose weight

The idea that hot water can aid weight loss is another common claim. There are several aspects to this statement. One involves metabolism, or “fat burning.” The claim is that hot water “melts” fat.

Verdict: Again, definitely a myth. Drinking hot water has no effect on your metabolism. What works? Your metabolism is regulated by your hormones, your level of physical activity, and the amount of calories you eat or drink. If you’re trying to lose weight, exercise is your best bet.

Myth or fact? Hot water reduces appetite

A related claim is that hot water helps you feel less hungry. In itself, this is a myth. But drinking water, hot or cold, before meals can help you feel fuller, which means you’ll likely eat less. This includes unhealthy foods. “Avoiding overeating can steer you away from empty calories,” Perry says.

Verdict: Water, hot or cold, does not in itself make you less hungry. But it can help fill your stomach while you eat, making you feel full faster.

Myth or fact? Hot water improves circulation

Blood circulation is another area where hot water is sometimes talked about as having surprising benefits. The idea is that drinking hot water increases your core temperature, which expands your blood vessels and improves blood flow.

But that’s not how your body works, notes Perry.

By the time the hot or warm water reaches the stomach, it has cooled. So there is almost no heat left to widen the blood vessels.

Verdict: Myth. What really works? Exercise, a healthy diet, and avoiding smoking have a much greater effect on blood flow and heart health.

Staying hydrated is what’s important

The idea that drinking warm water in the morning, or at any time, is better or worse than cold water is much more myth than fact. Although water itself is essential for life, temperature matters very little from a scientific perspective. Perry reminds, “Follow the evidence.”

But it’s not that there aren’t benefits to drinking hot or warm water. It can be comforting, relaxing and, if you have a sore throat, calming. If you prefer it to cold water, opting for it can help you drink the right amount of water you need each day.