Fatigue is hard to describe. You feel like you don’t have any energy and are tired all the time. But there’s not a specific cause, such as doing errands all day, working out, or other exertion. When you’re tired from exertion, if you get enough sleep that night, you usually feel better the next day. With fatigue, you feel generally tired all the time and lose interest in people and the things you normally like to do.

Fatigue is the most common side effect of breast cancer treatment. Some doctors estimate that 9 out of 10 people experience some fatigue during treatment. Fatigue from treatment can appear suddenly and can be overwhelming. Rest doesn’t ease fatigue and it can last for months after treatment ends.

Symptoms of fatigue include:

  • lack of energy
  • sleeping more
  • not wanting to do normal activities or being unable to do them
  • paying less attention to personal appearance
  • feeling tired even after sleeping
  • trouble thinking or concentrating
  • trouble finding words or speaking

Several breast cancer treatments can cause fatigue, including:

  • surgery
  • chemotherapy:
    • carboplatin (brand name: Paraplatin)
    • Gemzar (chemical name: gemcitabine)
    • Halaven (chemical name: eribulin)
    • Ixempra (chemical name: ixabepilone)
    • Mitomycin (chemical name: mutamycin)
    • mitoxantrone (brand name: Novantrone)
    • Taxotere (chemical name: docetaxel)
    • thiotepa (brand name: Thioplex)
    • vincristine (brand names: Oncovin, Vincasar PES, Vincrex)
  • radiation therapy
  • hormonal therapy:
    • Arimidex (chemical name: anastrozole)
    • Aromasin (chemical name: exemestane)
    • Evista (chemical name: raloxifene)
    • Fareston (chemical name: toremifene)
    • Faslodex (chemical name: fulvestrant)
    • Femara (chemical name: letrozole)
    • tamoxifen
  • some targeted therapies:
    • Afinitor (chemical name: everolimus)
    • Enhertu (chemical name: fam-trastuzumab-deruxtecan-nxki)
    • Herceptin Hylecta (chemical name: trastuzumab and hyaluronidase-oysk)
    • Ibrance (chemical name: palbociclib)
    • Kadcyla (chemical name: T-DM1 or ado-trastuzumab emtansine)
    • Kisqali (chemical name: ribociclib, formerly called LEE011)
    • Lynparza (chemical name: olaparib)
    • Margenza (chemical name: margetuximab-cmkb)
    • Nerlynx (chemical name: neratinib)
    • Perjeta (chemical name: pertuzumab)
    • Phesgo (chemical name: pertuzumab, trastuzumab, and hyaluronidase-zzxf)
    • Piqray (chemical name: alpelisib)
    • Talzenna (chemical name: talazoparib)
    • Tykerb (chemical name: lapatanib)
    • Verzenio (chemical name: abemaciclib)
  • immunotherapy:
    • Jemperli (chemical name: dostarlimab-gxly)
    • Keytruda (chemical name: pembrolizumab)
    • Tecentriq (chemical name: atezolizumab)

Many pain medications, such as codeine and morphine also can cause fatigue.

Fatigue can be made worse by other breast cancer and treatment side effects such as:

Poor nutrition also may play a role in causing fatigue. Eating less and not getting enough of the nutrients you need because of treatment side effects can cause fatigue.

Managing fatigue

If you think you’re experiencing fatigue, talk to your doctor. If possible, give your doctor specific information about your fatigue. Instead of saying, “I’m tired all the time,” give an example such as, “I get tired when I walk up the 5 stairs to my office.”

Because there are so many causes of fatigue, there’s no one medicine that can relieve fatigue. Together, you and your doctor can figure out ways to solve your fatigue.

Some complementary and holistic medicine techniques have been shown to reduce fatigue, including:

  • acupuncture
  • massage
  • meditation
  • Reiki
  • tai chi
  • yoga

Research and anecdotal evidence shows that lifestyle changes, such as exercising more, relieving stress, and eating a healthy, well-balanced diet can help ease fatigue.

Get moving

The American Cancer Society recommends that people who have been diagnosed with breast cancer exercise regularly (about 4 hours per week) to improve their quality of life and physical fitness. You can start slowly. Four hours of exercise a week may sound impossible if you’re a lifelong couch potato or if you’re sore from surgery, too busy with radiation therapy, or exhausted from chemotherapy. It’s hard to force yourself to exercise when you barely have enough energy to get out of bed or off the sofa.

Start slowly, perhaps walking for 15 minutes a day, and then gradually increasing the amount of time you spend exercising. You may need months to work your way up to 4 hours a week, but that’s fine. Even during treatment, taking short, slow walks up and down the street or around the block can be very helpful. Then you can progress to gentle exercise, such as yoga or tai chi.

Staying physically active is the key. Short spurts of activity here and there are good. But it’s even better to build up to one long period of exercise that lasts from 15 minutes to an hour (or longer, if you can).

If you’re not sure how to start exercising, you might want to visit a gym or make an appointment with a personal trainer to learn about different types of exercise. Make sure you tell the trainer about your health situation. Some people prefer exercising in their homes using videotapes or DVDs. Other people find great joy in gardening or yard work, as opposed to organized moderate exercise. Walking with a friend is a great way to socialize AND get the benefits of exercise.

Eat a healthy, well-balanced diet

You can fight fatigue by eating enough and trying to get all the nutrients you need. Create a healthy diet that is full of fruits and vegetables and whole grains. Make sure you eat foods that help you meet any new nutritional goals you and your doctors have set.

If you’re fighting fatigue, it’s important to make sure you’re getting enough protein as well as total calories. These amounts will be different for different people. Together, you and your registered dietitian and your doctor can come up with an eating plan that works for you.

Here are some general guidelines for how much protein and calories you need:

  • If your weight is staying about the same during treatment, you need 15 calories a day for each pound you weigh. So if you weigh 160 pounds, you need 2,400 calories a day to maintain your weight.
  • If you’ve lost weight during treatment, add another 500 calories to your daily diet. So if you weighed 130 pounds and lost weight during treatment, you need 1,950 plus 500, which equals 2,450 calories a day.
  • Protein helps heal and rebuild tissues. During treatment, eat half a gram of protein for each pound you weigh. So if you weigh 160 pounds, try to get 80 grams of protein in your diet each day.

You should also make sure to get enough vitamins and minerals. Getting these nutrients from foods rather than from supplements is best. But if you aren’t eating very much because of treatment side effects, ask your doctor about taking a multivitamin.

Also make sure you’re drinking enough liquids, especially water. If you have side effects such as vomiting and diarrhea, you need to drink more liquids than normal. Besides water, good choices are fruit juice, milk, and broth. Caffeinated beverages (coffee, tea, soda pop) actually can dehydrate you, so stick to other choices.

How to eat if you’re fatigued

  • Cook in bulk. When you have the energy to cook, make a large batch of something nutritious (vegetable pasta, tuna casserole, rice and beans) and freeze it in single-serving containers. Then when you’re too fatigued to cook, you can quickly heat one container and eat. If your friends or family offer to cook for you, ask them to do the same.
  • Eat a lot when you’re feeling good. Try to eat your biggest meal when you have the most energy and the biggest appetite. If you get tired by the end of the day, eat more at breakfast and lunch.
  • Eat several nutritious snacks during the day to boost your calorie and protein intake. String cheese, raisins, yogurt, baby carrots, and cut-up vegetables are easy to keep handy. This way you don’t have to face eating a big meal.
  • Try a prepackaged liquid nutritional supplement or an energy bar rather than skip a meal entirely. Every little bit helps.

Learn more on our Eating When You’re Fatigued page.

Other tips to manage fatigue:

  • Try a catnap. Beware of long naps, though. You might end up wide awake in the middle of the night. Daytime naps should be no more than 30 minutes, so you won’t fall into deep sleep. (Waking up groggy usually means you’ve napped too long.) If you find you need a nap every day, take it at a regularly scheduled hour, but try not to nap after 2 p.m.
  • Keep to a routine. Go to bed at the same time each night and get up at the same time each morning. Don’t stay in bed after you wake up. Make sure you get enough sleep and that you sleep for the same amount of time each night.
  • Keep a diary of how you feel each day. Keep a daily diary of your fatigue to identify when it’s the worst and when it’s least troubling.
  • Plan activities during the times you have the most energy. Schedule rest periods when your energy is lowest. Make sure you balance each activity with a rest period if you need it.
  • Organize each day. Figure out what you have to do and when you need to do it. Pacing yourself helps to conserve your energy.
  • Ask for help. Accept offers of help and goodwill from family and friends. If no one has offered to help and everyone seems too busy, ask for what you need — even if asking is one of the hardest things for you to do. Get help with little things: taking out the trash, folding the laundry, or paying bills. Keep a list of things you need done so when people ask what they can do, you can give them the list.
  • Join a support group. Sharing your feelings with others can ease the burden of your fatigue and give you more ideas about how you can cope with the condition. Your nurse or doctor can put you in touch with a support group in your area. For an online support group, visit the Breastcancer.org Discussion Boards.
  • Keep lists and make notes to remind you of important things if your memory and concentration are affected by fatigue. Also, give yourself more time for activities that take concentration.
  • Be kind to yourself. If you’re fatigued, don’t beat yourself up because you can’t do what you’re “supposed” to do. That browbeating takes energy you can’t afford to waste and can add to depression. Do nice things for yourself and give yourself permission to rest and recover, for as long as it takes.

To read more, visit our Managing Fatigue section.

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