Here’s what you should understand about cancer-related fatigue.

As someone who has walked the caregiver’s path myself, I know firsthand how confusing and frustrating it can be to watch your loved one battle cancer-related fatigue (CRF). It’s one of the most common side effects of both cancer and its treatment—yet one of the least understood. And because cancer fatigue isn’t visible, caregivers sometimes struggle to gauge how serious it really is.

This article explains what cancer fatigue is, why it happens, and what you—as a caregiver—can do to help your loved one cope more comfortably day to day.

What Is Cancer Fatigue?

Cancer-related fatigue is a deep, overwhelming exhaustion that doesn’t improve with rest or sleep. Unlike normal tiredness after a long day, this type of fatigue can affect a person physically, mentally, and emotionally—sometimes all at once.

People living with Waldenström macroglobulinemia (WM) and other blood cancers often describe it as feeling “drained to the bone.” It can make even simple activities—like showering, reading, or walking across a room—feel like running a marathon.

For caregivers, it’s important to recognize that fatigue isn’t a sign of weakness or laziness. It’s a physiological response to both the disease and its treatment.

Why Cancer Fatigue Happens

Cancer fatigue has many causes, often layered on top of each other:

• The cancer itself — Tumors and malignant cells release substances that disrupt the body’s regular metabolism, changing how energy is produced and used.

• Treatment side effects — Chemotherapy, immunotherapy, radiation, and targeted drugs all damage healthy cells along with cancer cells, requiring enormous energy to repair.

• Anemia — A low red blood cell count reduces oxygen delivery to tissues, which leaves the body constantly struggling for energy.

• Sleep disruption — Pain, anxiety, steroids, or treatment-related hot flashes can all interfere with deep, restorative sleep.

• Nutritional and hydration issues — Nausea, loss of appetite, or changes in taste make it difficult to maintain adequate calories and fluids.

• Emotional stress — Depression, anxiety, or fear of relapse can all amplify the sense of exhaustion.

CRF can also occur from any combination of these causes. It could prove difficult for your loved one’s hematologist-oncologist to pinpoint an exact reason.

The key takeaway: Cancer fatigue is far more than merely “being tired.” It’s a complex medical symptom influenced by both body and mind.

How to Recognize Cancer-Related Fatigue

Caregivers are often the first to notice patterns of fatigue their loved one might not mention. Look for these signs:

• They sleep longer but wake up just as tired

• They lose interest in hobbies or conversation

• Tasks that were once easy now feel impossible

• Moving slower than usual

• They become more forgetful or have trouble focusing (“chemo brain”)

• Mood changes, such as irritability or withdrawal

Keeping a fatigue journal can help your healthcare team identify possible triggers—such as medication changes, dehydration, or activity overload.

What Caregivers Can Do to Help

While cancer fatigue can’t always be eliminated, caregivers can make a meaningful difference in daily comfort and energy management.

1. Encourage Gentle Movement

Counterintuitive as it may sound, light physical activity—such as short walks or stretching—can help reduce fatigue over time. Even 10–15 minutes a day helps improve circulation, mood, and sleep quality.

2. Plan Balanced Nutrition and Hydration

Small, frequent meals that include protein, healthy fats, and complex carbohydrates help keep blood sugar levels stable. Encourage water, herbal teas, and electrolyte drinks. Dehydration alone can worsen fatigue dramatically.

3. Build Rest Into the Routine

Schedule regular rest periods, but keep them brief (no more than 30 minutes) to minimize disruptions to nighttime sleep. Encourage your loved one to rest before they feel overtired.

4. Simplify the Day

Fatigue often makes multitasking impossible. Help prioritize what must get done and postpone or delegate the rest. “Good enough” is perfectly fine during cancer treatment.

5. Watch for Treatable Causes

Report persistent or worsening fatigue to the oncology team. They can check for anemia, thyroid changes, medication side effects, or mood disorders. These are all treatable conditions that contribute to fatigue.

6. Take Care of Yourself, Too

Caregiver fatigue is real. Supporting someone with cancer is emotionally taxing, especially when their energy is low and needs are high. Schedule breaks, accept help, and nourish your own body and spirit so you can remain strong for them. Remember that it is okay to ask trusted friends and family to help.

When to Call the Hematology-Oncology Team

Reach out to the oncology or hematology office if your loved one:

• Sleeps more than 16 hours a day

• Experiences new shortness of breath, dizziness, or confusion

• Has sudden drops in blood pressure or appetite

• Feels hopeless or severely depressed

Timely communication can prevent small issues from becoming medical emergencies.

The Takeaway: Cancer Fatigue Is Real—and Manageable

Cancer fatigue is one of the toughest side effects for both patients and caregivers, but understanding it gives you power. By recognizing what’s happening inside the body and responding with empathy, structure, and collaboration with your care team, you can help your loved one reclaim moments of strength and normalcy.

As a caregiver myself, I’ve learned that pacing, patience, and compassion make all the difference. Every small act—serving a nourishing meal, creating a calm space to rest, encouraging a brief walk—helps your loved one fight not just the disease, but the exhaustion that comes with it.