• Researchers estimate that 90 percent of people with breast cancer experience fatigue during treatment.
• Fatigue can be caused by the cancer diagnosis, the disease itself, and breast cancer treatments.
• Talk to your health care team about potential solutions that may help ease your fatigue.

The most common side effect of treatment for breast cancer is fatigue, or feelings of extreme tiredness or exhaustion. In fact, some health care professionals estimate that 90 percent of individuals with breast cancer experience at least some fatigue during their treatment.

This fatigue is often overwhelming and can emerge abruptly without any apparent cause. It isn’t cured by rest or good quality sleep, and it may last for months or even years past the end of treatment. In individuals with metastatic breast cancer, fatigue can last a long time, but that doesn’t mean this symptom is permanent. Fatigue in breast cancer can be managed — both at home and with your health care team’s guidance.

What Causes Fatigue in Breast Cancer?

Many factors cause people with breast cancer to experience fatigue, including the condition itself as well as treatments, such as chemotherapy, radiotherapy (radiation therapy), surgery, and medications. As one MyBCTeam member wrote, “I feel so beat out after treatments. It takes a lot to just take a shower or brush my teeth.”

In addition, individuals with breast cancer often face unique stressors, including multiple diagnoses, emotional health troubles, and life obligations. All of these components can make for a noticeable lack of energy and feelings of fatigue.

Breast Cancer

People with breast cancer often experience fatigue before their initial diagnosis and treatment. Cancer-related fatigue is different from other types of fatigue. It generally isn’t the kind of fatigue you can relieve through rest, relaxation, or sleep. This fatigue is severe and can make you feel miserable.

Breast cancer is routinely accompanied by depression, anxiety, pain, and sleep disturbance. All of these can lead to a high level of distress and exhaustion.

Chemotherapy

Chemotherapy has a large number of potential side effects that can easily cause cancer-related fatigue. Chemotherapy aims to destroy or slow the growth of fast-growing cancer cells. Unfortunately, it can also harm or destroy some healthy cells.

Chemo may decrease your red blood cell count and lead to anemia, a symptom characterized by feelings of tiredness and weakness. Chemotherapy also commonly depletes the white blood cells, which increases susceptibility to infections.

Individuals undergoing chemotherapy typically feel the most fatigue during the days just after each treatment. That fatigue generally decreases up until the next chemo treatment. Studies have shown that people have the worst fatigue around the midpoint of their cycles of chemotherapy.

MyBCTeam members often talk about the toll chemotherapy takes on their energy levels. “I have bone metastasis,” one member wrote. “The fatigue is horrible for me. I just finished my fifth chemo.”

Some fatigue subsides when chemotherapy is complete, but people don’t usually feel back to normal until more than a month after their last treatment. Anxiety, depression, pain, and anemia also add to the fatigue of chemotherapy.

Radiation Therapy

Radiation therapy, or radiotherapy, kills cancer cells using high-energy rays. Only the cells in the part of the body being treated with radiation are affected. Breast cancer radiotherapy typically lasts anywhere from five days to six weeks, depending upon the treatment. In addition to cancer-related fatigue, radiation may leave a rash in the area treated.

“I had incapacitating fatigue with radiation,” one MyBCTeam member wrote. “By the time I got home after the treatments, I had to take a nap.”

Medications

Some cancer drugs may cause fatigue. There are many types of medications oncologists may prescribe. Many people who take cancer medications find severe tiredness to be the most worrisome side effect.

In addition to chemotherapy, some of the drugs that may cause severe fatigue include:

• Painkillers
• Immunotherapy
• Targeted therapies and drugs
• Hormone therapy

It’s important to remember that drugs affect people differently. One person may have fatigue from one medication, while another doesn’t. There are a few factors that may influence whether you experience fatigue and to what degree. They include the dosage you receive, how your body reacts to the medication, and the combination of drugs you’re taking.

Surgeries

Surgery is another cause of fatigue in breast cancer. Both the surgery itself and the recovery period can be exhausting enough. Worrying about the success of the surgery and the state of your cancer can yield additional fatigue.

“The emotions and stress of having an upcoming surgery can be really taxing on the body,” one MyBCTeam member wrote. Another said, “I am three weeks out of surgery and still tired.”

Trying To Live a ‘Normal’ Life

The world doesn’t stop with a breast cancer diagnosis. Many people must still keep up with the responsibilities of everyday life. Balancing work, school, home life, and other responsibilities with things like doctor’s appointments and medication management can be stressful and fatiguing.

“I will be going back to work soon after a double mastectomy,” one MyBCTeam member wrote. “I am nervous — my anxiety is high.” Another said, “Coming back to work was a good thing for me. Less time to think so much.”

Learn ways to reduce stress from living with breast cancer.

Multiple Diagnoses

Many people living with breast cancer have additional conditions. In some cases, breast cancer treatments and medications cause other disorders or diseases. In other cases, an individual may have a preexisting condition that itself causes fatigue.

Some conditions MyBCTeam members have faced alongside breast cancer include:

• Iron deficient anemia
• Colitis
• Heart attacks
• Ministrokes
• Thyroid problems
• Fibromyalgia
• Other cancers

As one member shared, “I only had radiation, not chemo, and I didn’t get energy back for two years. But I have an autoimmune disease too, which probably affected my recovery.” They went on to encourage other members to “Hang in there. It will get better over time.”

Living With Fatigue and Breast Cancer

Fatigue can be a long-lasting symptom and side effect of breast cancer and its treatments. As one member shared, “I am four-and-a-half years out and still have to ‘listen’ to my body. There are times when I feel so tired.”

There are treatments and symptom management techniques that are part of a palliative care program to help reduce the related symptoms of both the cancer and its treatments. These can help people with breast cancer find relief from their fatigue.

The goal of these approaches is to improve your well-being and quality of life. Some of these methods can be done alone, while others may require a specialist’s medical advice. As always, consult your health care team before trying a new method to manage your fatigue.

Keep Moving

While fatigue can make exercise feel like a challenge, not getting enough physical activity can actually worsen fatigue and leave you feeling even more tired. One popular form of light activity for people with breast cancer is walking. Whether you’re walking your dog, with a couple of friends, or on your own, you’re working your muscles and ultimately boosting your energy levels. You can start out slow and work up to longer walks — the most important thing is consistency.

Be sure to check in with your doctor before beginning a new exercise routine. They can also refer you to a specialist, such as a physical therapist, who can work with you to devise the right exercise program for you to help reduce your level of fatigue.

Let Yourself Rest

Though exercise is an important part of your fatigue-management toolkit, that doesn’t mean you need to dive head-first into vigorous activity. Instead, balance light or moderate exercise with periods of rest, which will allow your body time to recover.

One MyBCTeam member shared the importance of letting yourself rest after exercise: “I exercise daily, and that boosts me for a little while right after, but then a few hours later, I hit the wall, and I need to lay down or I feel I will literally fall asleep standing up.”

Diet and Nutrition

Getting the right nutrients is important for everyone — especially those with breast cancer. Eating a healthy diet filled with fruits, vegetables, and protein can help to keep your strength up, keep your immune system strong, and build up your body’s tissues.

It can be difficult to eat right — if at all — when undergoing breast cancer treatment. As one MyBCTeam member shared, “I have no appetite. Nothing tastes good. My weight stays the same, but I have no energy. I know they probably are connected.”

Other dietary preferences or restrictions can also make getting the right nutrients a challenge: “I ate an extremely healthy vegan diet before cancer,” wrote one member. “It was very hard with chemo to eat healthily.”

You may want to speak with your doctor about your diet or ask for a referral to a registered dietitian who specializes in working with people with cancer. They will work with you to come up with a unique dietary plan tailored to your nutritional needs.

Take Care of Your Mental Health

Fatigue can be a side effect of depression — a common symptom of breast cancer that can also result from treatments. If you feel depressed, anxious, or generally down after your diagnosis, talk to your cancer care provider. They can refer you to a specialist, such as a therapist or a psychiatrist, who specializes in working with people living with breast cancer. These specialists might suggest treatments that include:

• Cognitive behavioral therapy (which has been found to help with fatigue associated with breast cancer)
• Relaxation techniques, such as meditation and mindfulness
• Medications to treat underlying depression and anxiety

Learn more ways to feel your best with metastatic breast cancer.

Talk with Members Who Understand

On MyBCTeam, you’ll meet others with breast cancer, as well as their loved ones who support them. Here, breast cancer survivors and people with breast cancer come together as a support group to share advice and personal stories with others who understand.

How have you managed fatigue with breast cancer? Share your experiences and tips in the comments below or by posting on MyBCTeam.