Editors note: Original publish date: Aug 30, 2023 – Updated on June 24, 2024
Water is essential to maintaining human life and makes up most of one’s body weight. Consuming enough water and fluids every day can prevent dehydration and support the correct functioning of the body.
Key Points
- By drinking enough fluids, the kidneys are able to effectively clear waste products, sodium, and urea from the bloodstream.
- Kidney stones and urinary tract infections (UTIs) are more likely to occur in people with chronic insufficient fluid intake.
- Patients with kidney failure or late-stage chronic kidney disease and those on dialysis must carefully monitor their daily fluid intake.
- Drinking enough fluids—ideally clean water—may help maintain kidney and overall health.
The Kidneys and Hydration
The kidney’s primary role in the human body is to balance fluids and remove waste. They purify the blood by excreting and filtering out waste products such as excess sodium and urea. These waste products are removed from the body via the urine. The production of urine is a complex process, with the kidneys themselves producing about 1-2 liters of urine per day to filter roughly 180-200 liters of blood.
The kidneys also play an essential role in the following:
- Maintaining electrolyte levels by balancing potassium and sodium
- Regulating blood pressure
- Regulating the creation of red blood cells in the bone marrow
- Producing an active form of vitamin D
About 60-70% of body weight is made up of water. The body’s muscles and kidneys are made up of 79% water. Water is an integral part of the body and its ability to function. Some other essential functions that water is a part of include:
- Removing waste products from the bloodstream in the form of urine
- Keeping the blood vessels open
- Regulating the body’s hormones and chemicals
- Balancing the body’s temperature
- Helping to deliver oxygen throughout the body
If you do not consume enough water or fluids, this can lead to dehydration. Dehydration affects the body’s delivery system, making it more difficult to function properly. Signs and symptoms of dehydration in adults may include:
- Low blood pressure (hypotension) with a high heart rate
- Muscle cramps
- Dark-colored urine that has a strong smell
- Loss of appetite
- Tiredness
- Headache
- Constipation
Does dehydration affect the kidneys?
Mild dehydration can impair normal bodily functions, leaving you feeling tired or giving you a headache. Severe and persistent dehydration can lead to electrolyte imbalances, kidney issues such as kidney failure and kidney stones, and heart-related illnesses like heat stroke.
How do you hydrate your kidneys?
Clean water is one of the best sources of hydration for the kidneys as it contains no additives, preservatives, or colorants. A common misconception is that you have to drink eight glasses of water or fluids per day; however, everyone is different and has varying water needs based on their lifestyle and exercise intensity, disease state, climate, and whether you are breastfeeding or pregnant.
How does Dehydration affect the Kidneys?
The kidneys need proper hydration to function properly. Dehydration, especially chronic dehydration, results in the production of urine with a higher concentration of waste products and minerals.
Nephroluthiasuis, also commonly called kidney stones, are crystal concretions (hard deposits of salts and minerals) formed in the kidney and can affect any part of the urinary tract. These crystals form when there is a high concentration of oxalate, cystine, calcium, or phosphate with too little liquid. These crystals then build up in the kidneys, forming solid stones.
Regardless of size, kidney stones try to pass through the urinary system and may cause damage. Large kidney stones that are unable to pass through the urethra or ureters can cause severe pain and urinary tract infections.
Ensuring that you are adequately hydrated is essential to keeping your urine diluted and reducing the risk of kidney stone formation. UTIs and kidney stones can lead to kidney damage if not treated timely. Dehydration can also block the kidneys with myoglobin (muscle proteins).
How to maintain or improve water intake to improve kidney function
The general recommendation is eight glasses of fluids per day. While everyone has different daily water requirements, this general recommendation is based on the fact that we continuously lose fluids from our bodies and need to replace the fluids at an optimal result to survive.
Water helps prevent urinary tract infections (UTIs) and kidney stones. These two common conditions cause kidney damage and are often the result of chronic dehydration. Water also helps dissolve the antibiotics prescribed to treat UTIs. Producing more urine by drinking more water may help flush out the bacteria causing the infection.
Your urine is a great tool to check hydration levels at home. For the average person, consuming enough healthy fluids should result in your urine presenting as a light yellow. Dehydration can be indicated by urine that is a darker yellow color.
It is possible to drink too much fluid. Although not common in the average person, consuming too much water is possible, diluting blood sodium levels to a very low level. This may result in hyponatremia, a serious condition.
If you have kidney failure – less is more. When damage to the kidneys is severe (end-stages), they can no longer filter enough or any excess water. Your care team will advise daily fluid intake.
Hydration and Kidney Disease
People with chronic kidney disease, end-stage renal disease, and those on dialysis will take a different approach to hydration. Their daily fluid intake may be reduced or restricted. This is because the damaged kidneys are unable to remove the extra waste and water from the blood.
For kidney disease stages 1-2, you are encouraged to drink enough water to keep the kidneys hydrated and working well.
Once you reach kidney disease stages 3, 4, and 5 but are not yet on dialysis, you may be required to limit the amount of fluids you consume. Your dietician or doctor can help you with your daily fluid requirements. Your fluids are reduced or restricted, and you may experience fluid retention since the kidneys are no longer functioning correctly.
If you have kidney failure and are on dialysis, your daily fluid intake will be limited. Your renal dietician and nephrologist will tell you exactly how much fluid you can consume daily. You must strictly adhere to your daily fluid intake, as extra fluid in your body may be dangerous since it increases blood volume. Increased blood volume can result in complications such as:
- Edema (swelling)
- Heart failure
- High blood pressure (hypertension)
- Lung infections (from excess fluid)
- Poor nutritional status
- Decreased blood proteins
Any questions or concerns about dehydration and how much water and fluid you need to consume should be discussed with your care team or healthcare provider.
Hydration after a Kidney Transplant
Once you have received a kidney transplant, it is crucial to ensure that you are consuming enough fluids to keep it functioning correctly and ensure a successful recovery. Drinking enough water will help reduce the risk of developing kidney stones and infection.
Getting enough fluids post-transplant also helps control some of the side effects of your medications and helps the kidneys remove creatinine from the bloodstream. It is suggested to limit caffeine intake as it is a weak diuretic and contributes to the loss of fluids.
Not drinking enough fluids after your kidney transplant puts the new kidney under stress, which may cause damage.
Since you now have a healthy kidney, the amount of fluids you need may increase post-transplant. Your nephrologist and transplant care team will let you know your daily fluid requirements in the first 1-2 weeks after the kidney transplant.
Panoramic Health
Panoramic Health is an integrated provider group delivering the future of kidney care. Our mission is to improve patients’ outcomes by slowing disease progression and improving their quality of life. We do this through the distinctive capabilities of our comprehensive care model, which brings together an integrated provider group with operational support, clinical support, and data & analytics at scale.
Through partnerships with practices, providers, payers, and health systems, we work to advance the usage of clinically validated best practices and cutting-edge data analytics across a continuum of reimbursement models.
*The content presented in this article is for informational use only and should not be construed as medical advice or replace the medical advice of a qualified physician or renal dietician.
