Muscle cramps during dialysis can be painful, frustrating, and sometimes severe enough to make it difficult to complete a treatment. They most commonly affect the legs, feet, and calves and may occur during treatment or afterward.
If you experience muscle cramps during dialysis, you are not alone. Cramping is a recognized symptom among people receiving hemodialysis. Although researchers do not fully understand every cause, fluid removal and changes in blood pressure and the body’s fluid and chemical balance during treatment can contribute.
The good news is that your dialysis care team may be able to identify factors contributing to your cramps and make changes to help you feel more comfortable.
Why Do Muscle Cramps Happen During Dialysis?
Hemodialysis removes waste products and excess fluid from the blood. The amount of fluid that needs to be removed varies from person to person and from one dialysis session to another.
When a significant amount of fluid needs to be removed—or fluid is removed faster than your body can comfortably tolerate—your circulating blood volume can decrease. This may contribute to low blood pressure and muscle cramping during dialysis.
Cramps often occur later in a dialysis session, although they can happen at other times.
Several factors may contribute to dialysis-related muscle cramps, including:
- Rapid or excessive fluid removal
- Low blood pressure during dialysis
- Large fluid gains between dialysis treatments
- Changes in fluid and electrolyte balance
- Individual differences in the dialysis prescription
- Other medical, nutritional, muscular, or neurological factors
Because there can be several possible causes, recurring cramps should be discussed with your dialysis care team rather than treated on your own.
What Do Dialysis Muscle Cramps Feel Like?
Dialysis-related cramps are sudden, involuntary tightening of a muscle. They can range from mildly uncomfortable to intensely painful.
Many patients experience cramps in the:
- Calves
- Feet
- Toes
- Thighs
A muscle may feel hard or tight during a cramp. The discomfort may last for seconds or minutes, and soreness can sometimes remain afterward.
If cramps repeatedly happen near the end of your dialysis treatment, tell your nurse or nephrologist. The timing of your symptoms may provide useful information about what is triggering them.
Is Fluid Removal Causing My Cramps?
It can be a contributing factor.
One of the goals of hemodialysis is to remove excess fluid that has accumulated between treatments. This process is called ultrafiltration.
Removing too much fluid too quickly can contribute to symptoms such as muscle cramps, dizziness, nausea, headaches, weakness, and low blood pressure.
This is one reason your dialysis team pays close attention to your weight, blood pressure, symptoms, and fluid removal goals during each treatment.
Large Fluid Gains Between Treatments May Matter
The more fluid you accumulate between dialysis sessions, the more fluid may need to be removed during your next treatment.
For some patients, this can make dialysis more difficult to tolerate.
Following the fluid recommendations provided by your kidney care team can help reduce excessive fluid buildup between treatments. However, do not change your fluid intake on your own. Your recommended fluid allowance depends on factors such as your remaining kidney function, urine output, medications, dialysis prescription, and overall health.
Ask your dialysis team what fluid intake is appropriate for you.
What Should I Do If I Get a Muscle Cramp During Dialysis?
Tell your dialysis nurse or technician immediately.
Don’t assume that you simply have to tolerate the pain until it goes away.
Your care team can check your blood pressure and other factors and determine whether your dialysis treatment needs to be adjusted. Depending on the situation, clinical management may include changing or temporarily reducing fluid removal and other interventions.
Gentle stretching or massage of the affected muscle may also provide relief for some patients.
For example, if your calf cramps, gently straightening the leg and pulling the toes toward the shin may help stretch the muscle. However, follow the instructions of your dialysis care team, particularly while you are connected to the dialysis machine.
How Can I Help Prevent Muscle Cramps During Dialysis?
There isn’t one solution that prevents cramps for every dialysis patient. Prevention starts with figuring out what may be triggering your symptoms.
A few steps may help.
1. Tell Your Care Team About Every Episode
Don’t wait until cramps become unbearable.
Tell your nurse or nephrologist:
- When the cramps usually start
- Where they occur
- How painful they are
- How long they last
- Whether you also feel dizzy, nauseated, weak, or lightheaded
- Whether cramps continue after you leave the dialysis center
Patterns can help your healthcare team determine whether fluid removal, blood pressure, your dialysis prescription, medications, or another issue may be contributing.
2. Follow Your Recommended Fluid Plan
Try to stay within the fluid limits recommended by your kidney care team.
Managing fluid intake between treatments may help prevent large fluid gains and reduce how much excess fluid needs to be removed during a dialysis session.
Remember that “fluid” doesn’t only mean water. Depending on your individualized nutrition plan, your renal dietitian may ask you to account for beverages and foods that are liquid at room temperature.
If you’re frequently very thirsty, ask your renal dietitian for strategies that can make fluid management easier.
3. Discuss Your Target Weight With Your Dialysis Team
Your dialysis team may use a post-dialysis target or “dry” weight to help determine how much fluid should be removed.
Your needs can change over time.
If you’re repeatedly experiencing cramps, dizziness, weakness, or low blood pressure during treatment, tell your care team. They can evaluate whether your fluid removal goals and other parts of your dialysis prescription remain appropriate.
Never change your treatment time or target weight without discussing it with your dialysis team.
4. Don’t Skip or Shorten Dialysis Because of Cramps
Severe cramps can understandably make someone want to end treatment early. However, regularly shortening or missing dialysis can mean that your body does not receive the full treatment prescribed.
Instead, tell your dialysis team as soon as cramping begins. The goal is to address the symptoms while helping you receive adequate dialysis.
5. Ask Whether Gentle Stretching or Appropriate Exercise Could Help
Regular physical activity can provide important benefits for many people receiving dialysis, and some evidence suggests stretching may help with cramping.
However, the appropriate type and amount of exercise will depend on your health and physical abilities.
Ask your healthcare team whether stretching, walking, strengthening exercises, or another activity is appropriate for you.
Should I Take Magnesium, Vitamins, or Other Supplements for Dialysis Cramps?
Do not start supplements or medications for dialysis cramps without talking to your kidney care team.
You may see magnesium, vitamin E, carnitine, herbal remedies, or other products promoted online for muscle cramps. Research into several treatments has been conducted, but there is no single proven therapy that is appropriate for every dialysis patient.
This is especially important for people with kidney failure because the kidneys normally help regulate minerals and remove substances from the body. Supplements that seem harmless can sometimes accumulate or interfere with medications and treatment.
Your nephrologist should determine whether a medication, supplement, laboratory test, or change in dialysis prescription is appropriate for you.
When Should Muscle Cramps Be Reported?
Tell your dialysis team whenever cramping occurs repeatedly or interferes with your treatment.
You should especially speak up if your cramps occur along with:
- Dizziness or lightheadedness
- Nausea
- Weakness
- A significant drop in blood pressure
- Chest discomfort
- Shortness of breath
- Fainting or feeling as though you may faint
- New, severe, persistent, or unusual pain
Seek urgent medical attention for severe or concerning symptoms according to the instructions provided by your healthcare team.
Frequently Asked Questions About Muscle Cramps and Dialysis
Are leg cramps normal during dialysis?
Muscle cramps are a recognized complication of hemodialysis, particularly in the legs. However, frequent or severe cramps should not simply be ignored. Tell your dialysis team so they can look for possible contributing factors.
Why do I cramp near the end of dialysis?
Cramps may occur later in treatment as fluid is progressively removed from the body. Fluid-volume changes and low blood pressure can contribute, although dialysis-related cramping can have multiple causes.
Can removing too much fluid during dialysis cause cramps?
Rapid or excessive fluid removal can contribute to cramping and low blood pressure. Your dialysis team determines your fluid removal goal based on your individual circumstances.
Can drinking more water prevent dialysis cramps?
Not necessarily. People receiving dialysis often need individualized fluid limits. Drinking additional fluid without your healthcare team’s advice may cause excessive fluid accumulation between treatments and potentially make the next dialysis session more difficult.
Talk with your care team rather than increasing your fluid intake on your own.
Should I take magnesium for dialysis leg cramps?
Not unless your healthcare provider recommends it. Researchers have investigated magnesium and other treatments for dialysis-related cramps, but evidence remains limited, and supplements can pose additional concerns for people with kidney failure.
Can I stop dialysis when the cramps become painful?
Tell your nurse or technician immediately rather than stopping treatment yourself. Your dialysis team can evaluate the cause and determine whether the treatment needs to be adjusted. Repeatedly shortening dialysis can reduce the amount of prescribed treatment you receive.
Don’t Ignore Recurring Dialysis Cramps
Muscle cramps can be one of the more uncomfortable parts of hemodialysis, but you shouldn’t feel that you simply have to endure them.
Recurring cramps may provide your dialysis team with useful information about fluid removal, blood pressure, your target weight, or other aspects of your treatment.
Keep track of when your cramps happen and tell your dialysis care team about them. Small changes in your treatment plan or fluid management may sometimes make dialysis more comfortable.
Most importantly, never make major changes to your fluid intake, medications, supplements, dialysis time, or dialysis prescription without speaking with your healthcare team.
Medical Disclaimer
This article is intended for general educational purposes and does not replace medical advice, diagnosis, or treatment from your nephrologist or dialysis care team. Dialysis prescriptions, fluid restrictions, medications, and nutritional needs vary from person to person. Contact your healthcare provider with questions about your individual treatment.
References
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Hemodialysis.
National Kidney Foundation. Hemodialysis: How It Works, Types, and What to Expect.
National Kidney Foundation. Coping With Symptoms While on Dialysis.
Punj S, et al. A Survey on Dialysis-Related Muscle Cramping and a Hypothesis of Angiotensin II on Its Pathophysiology.
Varghese A, et al. A Higher Concentration of Dialysate Magnesium to Reduce the Frequency of Muscle Cramps: A Narrative Review.