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Why Hydration Is So Important

Mae Reilly, MS, RD, LDN, CNSC

As the cold winter months continue, we may think less about staying hydrated, but it’s important for many reasons. Drinking enough fluid helps regulate our body temperature, blood pressure, and heart rate. It helps lubricate our joints, and it keeps our organs functioning properly. Water also helps our body remove waste and toxins and transports nutrients throughout our body. Staying hydrated can also help promote bowel regularity and prevent constipation. Adequate hydration is especially important while undergoing cancer treatment. Drinking enough fluid can be challenging for patients who experience side effects from treatment including nausea, vomiting, decreased appetite, taste changes, diarrhea and/or fatigue. Some of these side effects can increase the risk of dehydration, which in turn can make it hard for the body to flush out chemotherapy substances or other medications and may put unwanted stress on the kidneys.

Here are some tips for staying well-hydrated:

  1. Use a refillable water bottle. Having water with you throughout the day can be a good reminder to drink more.
  2. Infuse water with sliced fruit or fresh herbs like mint. You can also try adding a splash of juice to water to add some flavor without adding too much sugar.
  3. Experiment with different herbal teas. Warm beverages can be both hydrating and satisfying in the winter months.
  4. Count all liquids towards your hydration goals. Think of broth, soup, sparkling water, smoothies, or anything that melts at room temperature like popsicles or ice cubes.
  5. Track your fluid intake. Consider filling a large pitcher with your daily water goal and drink from that throughout the day. You can also use a smartphone app to help keep track of daily fluid consumption.

How much fluid do you need?

Check with your healthcare team to determine how much fluid you should be consuming. Fluid requirements are highly individualized based on your age, sex, and activity level. Certain medications and cancer treatments can also affect how much water you need.


Electrolytes are minerals required for normal bodily functions such as maintaining regular heart rhythm, muscle contractions, nerve impulses, bone health, immune function and blood pressure maintenance. Some electrolytes include sodium, potassium, calcium and magnesium. You can consume these minerals from both food and drinks. Electrolyte imbalances can occur during cancer treatment if you are experiencing side effects like vomiting, diarrhea, dehydration or decreased oral intake. Additionally, certain medications or treatment regimens can also lead to electrolyte abnormalities. Your healthcare team may recommend including electrolyte containing beverages to help achieve healthy electrolyte levels. However, it’s important to know that these beverages can vary quite a bit in terms of which electrolytes they contain and how much electrolytes they contain. A Registered Dietitian or other members of your healthcare team can help evaluate your lab values and provide recommendations for fluid choices that would be best for you.

Can you count coffee or other caffeinated beverages towards your hydration goals?

Although caffeinated drinks may have a mild diuretic effect—they may cause the need to urinate—they don’t appear to increase the risk of dehydration. However, there may be other reasons to limit your caffeine consumption. It can cause headaches for some people and contribute to trouble sleeping for others. Adequate hydration is an important part of supporting overall health. Side effects from cancer treatment can make it challenging to meet your fluid needs. If you are concerned that you are not drinking enough or if want individualized recommendations, always check in with your healthcare team.

  1. Popkin BM, D’Anci KE, Rosenberg I. Water, Hydration and Health. Nutr Rev. 2010 Aug; 68(8): 439-458. Killer SC, et al. No evidence of dehydration with moderate daily coffee intake: A counterbalanced cross-over study in a free-living population. PLOS One. 2014;9:e84154.