The Importance of Hydration

July 1, 2009
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In this podcast, we'll review why people with cancer have a higher risk of dehydration, what symptoms to watch out for that may signal dehydration, and offer five simple ways to help keep your body's fluid supply in balance.


You're listening to a podcast from Cancer.Net. This cancer information website is produced by the American Society of Clinical Oncology, the world's leading professional organization for doctors that care for people with cancer.

Our topic today is the importance of hydration.                                        

Dehydration occurs when a person does not take in enough fluid or loses too much fluid. Without enough water, the human body cannot function properly, and people undergoing cancer treatment may be at a higher risk for dehydration. It is important for good health to learn how to stay hydrated, and recognize and treat dehydration before it becomes severe. In this podcast, we’ll review why people with cancer have a higher risk of dehydration, what symptoms to watch out for that may signal dehydration, and offer five simple ways to help keep your body’s fluid supply in balance.

Let’s start by looking at why water and proper hydration is important. Every cell and organ depends on water to perform its essential functions, including such things as transporting nutrients and oxygen throughout the body, regulating your body temperature, controlling your heart rate and blood pressure, and creating saliva. Therefore, it’s important for everyone to take in enough liquids daily, since each person’s body naturally loses water during a normal day through sweating, breathing, and going to the bathroom.

For people with cancer, there may be some additional reasons why the body is losing water, such as possible treatment side effects like diarrhea, nausea, and vomiting. Another cause is a high fever. Those who are being treated for cancer may have fewer white blood cells to fight infections that can lead to a fever. Illnesses, disabilities, and certain medications can also contribute to dehydration.

In addition, a person’s age may be a factor. In particular, older adults are at a higher risk for dehydration because the human body slowly loses the ability to conserve water as a person gets older. They may also be less likely to sense that they are thirsty and may not eat or drink enough, especially if they live alone.

In general, the longer you go without enough fluids, the more dehydrated you will become. In fact, relying on thirst alone is not enough, because many times a person may be dehydrated even if they don’t feel thirsty. That’s why it is important to identify other dehydration symptoms, such as:

  • Having a dry or sticky mouth, or a swollen tongue

  • Feeling tired, weak or irritable

  • Experiencing dizziness, nausea, or headaches

  • Having constipation, dark yellow urine or a decrease in urination

  • Having dry skin

  • Or, losing weight

The following five tips can help you keep your body's fluid balance in check and avoid dehydration:

Tip Number One: Drink lots of fluids. Drinking at least eight cups of water each day is a good rule of thumb. However, if you have any risk factors for dehydration like those we’ve discussed, you should drink more. If you dislike plain water, try drinking a flavored water or adding a slice of lemon. Other fluids such as juice and tea can contribute to your fluid count as well.

Number Two: Eat foods with high water content. While drinking water is the best source of hydration, many foods contain water and can help replenish lost fluids. Choose foods like lettuce, watermelon, and broccoli. Soups, popsicles, and yogurt also have high water content.

Number Three: Get help managing side effects. If you are undergoing cancer treatment that is causing side effects such as nausea, vomiting, or diarrhea, then talk with your doctor about ways to prevent or reduce these side effects, including medication.

Number Four: Don't wait to drink. Make a conscious effort to drink enough on a regular basis. And drink more often if you begin feeling ill, before you exercise, and before you go out into hot weather.

Number Five: Avoid foods and drinks that may contribute to dehydration. Beverages with sugar or caffeine may help to hydrate some, but are not as effective as low-sugar or non-caffeine beverages.

If you are experiencing mild dehydration, there are some things you can do to help replenish fluids. Consider sucking on ice chips or popsicles if you are having trouble drinking water or eating. Apply moisturizer to cracked lips and medication to mouth sores, so that drinking and eating is less painful.  If you are able to drink, take in small amounts frequently instead of a large amount at one time to avoid stomach upset. If you have diarrhea, be sure to select beverages that have sodium and potassium, which are naturally lost through the stool. And if you have fatigue, keep ice and drinks within reach so you don't have to get up more often than necessary.

Severe dehydration can be life-threatening and requires immediate medical treatment. These symptoms may include feeling extreme thirst, having a high fever or low blood pressure, and experiencing a rapid heartbeat. If your symptoms become severe, seek immediate medical care. In some cases, hospitalization may be necessary. Your doctor may also perform tests to determine the extent of dehydration and to figure out what is causing your fluid loss.

The amount of fluids a person should consume each day to stay hydrated can differ based on his or her health and lifestyle. A good first step is to talk with your doctor about how much water to drink to replenish fluids on a regular basis, as well as learn the signs of mild dehydration, and what to do before it becomes severe.  

For more information on this topic, contact your doctor or visit Thank you for listening to this Cancer.Net Podcast.