Yes, dialysis can cause several side effects, most commonly fatigue, muscle cramps, and low blood pressure. These symptoms are usually the result of the rapid removal of fluid and waste products from the blood during the treatment. While dialysis is life-sustaining, it is physically demanding on the body. Most side effects can be managed or minimised by adjusting the dialysis prescription, following dietary and fluid advice, or changing the frequency of the sessions.
The way you feel on dialysis is often linked to the balance of fluid in your body. In the UK, renal teams monitor patients closely during every session to ensure that these side effects are kept to a minimum. By understanding why these symptoms occur, you can work with your nurses and doctors to make your treatments as comfortable as possible.
What We Will cover in This Article
- Why ‘dialysis fatigue’ or the ‘washout’ effect happens
- The causes of painful muscle cramps during treatment
- How low blood pressure (hypotension) is managed on the machine
- The link between fluid weight gain and treatment side effects
- Strategies for reducing post-dialysis exhaustion
- When to report symptoms to your clinical team
Understanding ‘Dialysis Fatigue’ and the Washout Effect
One of the most frequent complaints from patients on haemodialysis is extreme tiredness, often called ‘dialysis fatigue’ or the ‘washout’. This is a feeling of total exhaustion that typically occurs immediately after a session and can last for several hours. It happens because the process of cleaning the blood and removing fluid is a high-energy task for the body. The rapid shift in the body’s internal chemistry and fluid levels can leave you feeling drained.
To manage this, many patients find that a short nap after dialysis helps. However, if the fatigue is persistent and prevents you from doing daily activities, it could be a trigger for your doctor to check your haemoglobin levels. Anaemia (low red blood cell count) is common in kidney patients and is a major cause of fatigue that can be treated with medication.
Muscle cramps and fluid removal
Muscle cramps are a common and often painful side effect that usually occurs toward the end of a dialysis session. These cramps are primarily caused by the removal of fluid from the tissues. If your body must give up a lot of fluid quickly to reach your ‘dry weight’, the muscles can contract painfully.
The best way to prevent cramps is to limit your fluid intake between sessions. If you gain less ‘fluid weight’, the machine can remove it more slowly and gently. If a cramp does occur during treatment, the nurses can trigger a ‘saline bolus’ (a small amount of salty fluid) or slow down the ultrafiltration rate on the machine to provide immediate relief.
Low blood pressure (Hypotension)
Low blood pressure is perhaps the most common side effect during haemodialysis. It happens when too much fluid is removed from the blood too quickly, causing the pressure in your veins and arteries to drop. Symptoms include feeling dizzy, nauseated, or suddenly hot and sweaty.
Clinical teams monitor your blood pressure frequently throughout each session. If it drops too low, the nurses will tilt your chair back, so your head is lower than your feet (the Trendelenburg position) to help blood flow to your brain. Long-term management of low blood pressure involves carefully adjusting your ‘dry weight’ the weight at which your body is in fluid balance without being dehydrated.
Comparing Common Dialysis Side Effects
The following table differentiates between the common side effects and their primary triggers:
| Side Effect | Primary Cause | Typical Sensation | Management Strategy |
| Fatigue | Chemical & fluid shifts | Feeling ‘washed out’ or heavy | Rest and anaemia check |
| Muscle Cramps | Rapid fluid removal | Sharp pain in legs or feet | Lower fluid gain between sessions |
| Low Blood Pressure | Dehydration of the blood | Dizziness, nausea, sweating | Adjusting ‘dry weight’ and pump speed |
| Itchy Skin | High phosphate levels | Persistent itching | Taking phosphate binders with food |
| Headaches | Change in blood chemistry | Throbbing or dull pain | Adjusting salt intake and machine settings |
Causes of long-term side effects
While most side effects are temporary and linked to the treatment sessions, some can be long-term. For example, persistent itchy skin (uraemic pruritus) is often caused by a buildup of waste products or high levels of phosphate in the blood. This is a common cause for discomfort that requires a combination of dietary changes and specialized creams.
Sleep problems and restless leg syndrome are also common causes of discomfort for dialysis patients. These are often triggered by the underlying kidney disease itself rather than the dialysis process. Regular exercise, even gentle walking, and ensuring your dialysis is ‘adequate’ (cleaning the blood effectively) are the best ways to combat these long-term issues.
Differentiation: Standard vs. Intensive Dialysis
It is important to differentiate between standard hospital dialysis (three times a week) and more intensive options like home haemodialysis. Patients who dialyse more frequently for example, five or six times a week for shorter periods often report significantly fewer side effects.
This differentiation occurs because the fluid removal is much gentler when done daily. There is no ‘long gap’ over the weekend for fluid to build up, which reduces the triggers for cramps and low blood pressure. Many patients find that by switching to more frequent home dialysis, the ‘washout’ effect disappears almost entirely, allowing them to return to a more active life.
Summary
Dialysis side effects like fatigue, cramps, and low blood pressure are common but manageable. Most are caused by the rapid removal of fluid and waste from the body. By following fluid restrictions and working closely with your renal team to fine-tune your ‘dry weight’ and dialysis prescription, you can significantly reduce these discomforts and improve your energy levels.
Why do I feel sick during dialysis?
Feeling nauseated is often a sign of a drop in blood pressure. It can also be a reaction to the blood being cleaned too quickly if you are new to dialysis.
Does everyone get cramps?
No, many patients never experience cramps. They are most common in people who gain a lot of fluid weight between treatments.
Can I take a nap during dialysis to help with fatigue?
Yes, sleeping during the session is perfectly fine and is a good way to pass the time while the machine works.
Will my side effects get better over time?
Often, yes. Your body needs time to adjust to the treatment, and your clinical team will adjust your settings to find the ‘sweet spot’ for your comfort.
Authority snapshot
This article was developed based on UK clinical standards for renal care. Dr. Stephan Brincat is a Consultant Nephrologist at St George’s University Hospital NHS Foundation Trust in London. He has extensive experience in managing acute and chronic kidney disease, with a particular focus on haemodialysis and the long-term management of renal failure. His work at St George’s includes overseeing the care of patients on dialysis and ensuring high standards of patient comfort and safety during treatment.
