Fatigue After Chemotherapy: Why It Happens and What You Can Do

Fatigue after chemotherapy

Chemotherapy induced fatigue is common and real. You might feel tired, weak, or like you have no energy. This can happen during chemotherapy, immunotherapy, or radiation. Many people also feel tired after surgery.

Fatigue is more than being sleepy. It does not always get better with rest. It can affect your mood, focus, and daily life. Share how you feel with your oncology team. They can help you find the causes and plan next steps.

Why does cancer treatment make me tired?

Fatigue can have more than one cause. During cancer care, you might feel tired because you:

Are sad, worried, or stressed
Aren’t eating enough, or not getting balanced nutrition
Have trouble sleeping, or do not get enough sleep
Have pain
Have anemia (low red blood cells), so your body gets less oxygen
Have other medical issues, such as infection or low hormone levels
Are taking medicines that cause drowsiness, like some pain or nausea medicines

Often, fatigue has several causes at the same time. That is why it helps to treat more than one area (sleep, mood, activity, and nutrition).

Will I need tests?

Maybe. Your doctor or nurse will ask about your symptoms and daily activities. They might order blood tests to look for causes that can be treated, such as anemia, infection, or low hormone levels. Ask what the results mean and how often you should be re-checked.

How long can chemotherapy induced fatigue last?

Fatigue can start soon after treatment begins. It may get worse near the end of a cycle. For many people, energy improves weeks to months after treatment ends. Some people feel better in a few months; others need longer. A smaller group has fatigue that lasts a year or more. Your team can help track changes over time.

What can I do on my own to feel less tired?

Exercise (even mild) – Moving your body is one of the best ways to fight fatigue. Try to be active most days, even if it is just a 5–10 minute walk. You can split activity into short chunks (for example, 3 walks of 10 minutes). Light strength moves, like using resistance bands or sit-to-stand from a chair, can also help. Talk with your care team before you start or change an exercise plan.
Why exercise matters: the science
- Randomized studies show that regular, moderate exercise lowers cancer-related fatigue by about 20% to 30% compared with usual care.
- Guidelines from oncology and sports medicine groups recommend aerobic activity plus light resistance training during and after treatment, tailored to your energy level.
- Exercise can also improve sleep, mood, and quality of life.
Do gentle yoga – Slow yoga with breathing and relaxation can reduce fatigue and help you sleep better. Many people do well with 1–3 short sessions per week. Choose beginner or restorative styles.
Lower your stress
- Ask family and friends to help with chores and errands.
- Take time off work or reduce hours if you can.
- Try relaxation, mindfulness, or guided breathing.
- Talk with a counselor or join a support group.
Save your energy
- Plan your day. Do the most important tasks when you have the most energy.
- Break big jobs into small steps. Rest between steps.
- Sit for tasks like showering or meal prep if that helps.
- Use tools like reachers, a shower chair, or a rolling cart.
Improve your sleep habits
- Keep a regular sleep and wake time.
- Limit naps to 20–30 minutes, and not late in the day.
- Avoid caffeine and alcohol in the late afternoon or evening.
- Keep the bedroom dark, quiet, and cool. Save the bed for sleep and intimacy.
Eat and drink enough – Small, frequent meals and hydration can keep your energy steadier. A registered dietitian can help you find foods that fit your treatment plan and taste changes. Ask your team before starting vitamins or supplements.
Track your energy – Keep a simple fatigue diary. Note your activity, sleep, meals, and how tired you feel (0–10). This helps you and your team see patterns and plan changes.

Is exercise really safe and worth it during treatment?

For most people, yes—light to moderate activity is safe and helpful. Studies in many cancer types show that exercise during treatment reduces fatigue and improves well-being. Start small and build slowly. Some days you may only manage a few minutes, and that still counts.

Check with your oncology team first, especially if you have anemia, low platelets, bone weakness, pain, dizziness, or balance problems.
On days you feel worse, do gentler activity, like stretching or short walks at home.
Stop and call your team if you have chest pain, trouble breathing, or feel faint.

When should I call my care team?

New or worsening shortness of breath, chest pain, or a fast heartbeat
Dizziness, fainting, confusion, or a severe headache
Fever of 100.4°F (38°C) or higher, chills, or signs of infection
Bleeding, easy bruising, or black/tarry stools
Unable to keep fluids down, very dark urine, or signs of dehydration
Fatigue so strong you cannot do basic daily activities

Are there treatments that might help my symptoms?

Depending on the cause, your team might suggest options such as:

Treatments for anemia – Some types can be treated with medicines that help your body make red blood cells or with blood transfusions.
Medicines for mood or sleep – If depression, anxiety, or insomnia is part of your fatigue, counseling and medicines might help.
Steroid medicines – In certain cases, short-term steroids can boost energy. They have side effects, so they are used with care.
American ginseng – Some studies show daily use can improve cancer-related fatigue for some people. Always talk with your team before taking it, as it can interact with other medicines.
Hormone treatment – In some men, low testosterone can add to fatigue. Your doctor can discuss if testing or treatment is appropriate.

Ask your oncology team which options fit your situation, and how they might interact with your cancer treatment.

Quick start: a gentle movement plan

Most days: Walk 5–10 minutes, 2–3 times. Add 1–2 minutes as you are able.
Twice a week: Light strength moves (chair stands, wall push-ups, bicep curls with light bands), 1–2 sets of 8–10 reps.
Most days: 5 minutes of stretching and deep breathing or gentle yoga.
Rest before you are exhausted. Use the “talk test”: you should be able to talk, not sing.

Helpful resources and references

Bring this article to your next visit and talk with your oncology team about a plan that fits your energy, safety, and goals.

Last reviewed: 2025-09-26