cancer fatigue on one side

Overview

Cancer-related fatigue is a deep, overwhelming tiredness that does not go away with rest. It is very common during and after cancer treatment. One-sided fatigue means this exhaustion or weakness is felt mainly on one side of your body, such as one arm or one leg. It can be a sign of other issues that need attention, so it is important to talk about it with your healthcare team.

General cancer fatigue is very common. However, notice that fatigue is mostly on one side only happens less often. When it does, it deserves a medical check to find out the cause.

It can affect anyone who has gone through cancer treatment, including surgery, radiation, chemotherapy, or immunotherapy. People who had surgery near nerves or lymph nodes, such as under the arm or in the groin, may be more likely to notice one-sided symptoms.

Symptoms

Common symptoms

• Deep tiredness that feels worse on one side of the body
• A heavy or weak feeling in one arm or leg
• Muscle fatigue in one side during physical activity
• Less endurance or strength in one limb
• Difficulty using one side as easily as the other

Symptoms in children

• Children may favor one side during play or daily activities
• They may say one arm or leg feels heavy or like it is not working properly
• They might become more fussy or less interested in playing due to fatigue

Symptoms in older adults

• Older adults may notice they are less steady on their feet or more likely to stumble
• One hand may feel clumsier for tasks like holding a cup or buttoning a shirt
• They might mistake the fatigue for normal aging, but it should still be discussed with the cancer care team

Causes

Main causes

• Nerve damage from surgery or radiation therapy
• Lymphedema, which is swelling from fluid buildup on one side
• Muscle deconditioning from favoring one side or being less active
• Anemia, which is a low red blood cell count
• Thyroid problems, especially after radiation to the neck area
• A blood clot in a deep vein, called deep vein thrombosis
• A stroke or transient ischemic attack (mini-stroke), which is rare but serious

Risk factors

• Surgery to remove lymph nodes in the armpit or groin
• Radiation therapy aimed at one side of the body
• A past stroke or mini-stroke
• Being inactive or spending long periods in bed
• Having heart disease, diabetes, or poor blood circulation
• Obesity or smoking

When to see a doctor

See a doctor urgently if:

• If one-sided fatigue or weakness appears suddenly over hours or a day, call your local emergency number.
• If the affected limb becomes swollen, painful, red, or warm, seek same-day medical care.
• If you have a fever or feel generally unwell along with one-sided fatigue, contact your cancer care team urgently.

Book a routine appointment if:

• Mention one-sided fatigue at your next follow-up appointment if it has been slowly getting worse over weeks or months.
• If it is affecting your balance, walking, or ability to do daily tasks, schedule a sooner visit.
• If you have any new symptoms such as a tingling sensation or weakness that is not sudden, discuss them with your doctor.

Diagnosis

Your doctor will start by talking with you about your symptoms, your cancer treatment history, and any other health conditions. They will do a physical exam, checking your strength, reflexes, and sensation on both sides. Depending on what they find, they may order tests to look for specific causes.

Tests that may be done

• Blood tests to check for anemia, thyroid problems, and other markers
• Ultrasound or CT scan if a blood clot or nerve compression is suspected
• Nerve conduction studies to see if nerves are working properly
• A stroke assessment, such as imaging of the brain, if sudden weakness ever occurs

What to expect at your appointment

The evaluation usually begins with a conversation and a physical exam. Most tests are painless and can be done in an outpatient clinic. If needed, your doctor will refer you to a specialist such as a neurologist, a physiotherapist, or a vascular specialist. You should receive a clear explanation of the results and a plan for next steps.

Treatment

Treatment for one-sided fatigue depends on the cause found. If nerve damage or muscle weakness is the reason, rehabilitation and exercise therapy can help rebuild your strength. If it is a blood clot, you will need urgent medical treatment to prevent complications. Your cancer care team will guide you with a plan that fits your situation.

Self-care at home

• Pace yourself and schedule short rest breaks during the day.
• Use the affected side as much as possible in daily activities to keep it active.
• Move gently and regularly; avoid sitting or standing still for long stretches.
• Prop up a swollen limb on pillows when resting, if recommended by your team.
• Wear shoes with good grip to help prevent falls.
• Ask family or friends for help with heavy lifting or tasks that feel exhausting.

Medical treatments

Your healthcare team may suggest physiotherapy or occupational therapy to improve strength and coordination. In some cases, they may treat an underlying problem such as anemia with nutritional support or other approaches. For a blood clot, medicines or procedures may be used to thin the blood or remove the clot. Always talk to your cancer team before starting any new medicine or supplement, including over-the-counter products.

When is surgery considered?

Surgery is rarely needed for fatigue itself. However, if a blood clot is present, a procedure may be needed to remove the clot or place a small filter in a large vein to protect the lungs. A vascular specialist will carefully discuss the options with you.

Living with this condition

Living with one-sided fatigue means tuning in to your body's signals. Plan your day around your energy highs and lows, and modify activities to make them easier. For example, sit down when you need to, use supports like a cane if it helps, and don't hesitate to ask for help. On low-energy days, give yourself permission to rest without guilt.

Lifestyle tips

• Take a short gentle walk or do stretching exercises every day if you are able.
• Use mobility aids like a walking stick or rollator if they improve your steadiness.
• Keep a symptom diary to track your energy and any changes.
• Talk to your cancer team about cancer rehabilitation programs.
• Protect the affected area from injury, as skin may be more fragile after treatment.

Diet and exercise

Try to eat balanced meals that include protein, fruits, vegetables, and whole grains. Drink enough water throughout the day. For exercise, start with very short, gentle sessions, such as five minutes of walking or chair-based movements. A physiotherapist can design a safe program for you. Do not push hard; the goal is to gently build back strength without over-tiring yourself.

Mental health and emotional wellbeing

One-sided fatigue can feel frightening and frustrating. It may affect your mood, confidence, and sense of independence. It is normal to feel anxious, sad, or angry. Sharing your feelings with a close friend, family member, or counsellor can make a big difference. Remember that your mental health is just as important as your physical health, and you deserve support.

Prevention

One-sided fatigue is not always preventable because it can be caused by cancer treatment itself. However, staying gently active before and after treatment, caring for your skin and limbs, and reporting new symptoms early can help reduce its impact. It also helps to eat well and maintain your kidney and liver health as directed by your doctor.

Complications

If left untreated

• A blood clot may travel to the lungs, which is a life-threatening emergency.
• Falls and injuries caused by weakness on one side.
• Long-term muscle loss, joint stiffness, or reduced mobility.
• Unrecognized stroke could lead to permanent disability.
• Worsening of cancer-related fatigue that interferes with daily life and recovery.

Long-term outlook

With the right medical care and support, most one-sided fatigue can improve over time. Your team can find the cause and help you rebuild your strength and confidence. Many cancer survivors go on to return to the activities they love. There is every reason for hope, especially when you reach out for help early.

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