Why does radiotherapy make you so tired

A cancer diagnosis changes your life. Depending on the type of cancer, treatments may include chemotherapy, bone marrow transplants, surgery, immunotherapy and radiation therapy, or a multidisciplinary approach that includes many of these treatments. In the series of tests and treatments one may produce unpleasant side effects, including excessive fatigue or tiredness. Radiation therapy tends to increase the feeling of fatigue, leaving many to question why, and what can be done about it. While patients often experience fatigue after radiation, it is not necessarily the direct result of your treatment.

It can be a symptom of a combination of factors, including:. For those who have never experienced fatigue, it is easy to assume it is simply tiredness.

However, fatigue is not the same as simply feeling sleepy. Everyone feels tired occasionally, but fatigue is often a chronic physical and mental exhaustion.

While feeling extremely tired is certainly a predominant symptom of fatigue, it often brings with it additional symptoms, such as:. The cancer itself may contribute to your sense of fatigue as well. While radiotherapy seeks to eradicate cancer by destroying cancer cells with radiation, it also increases the level of fatigue a person feels. A team of experts use technology to provide a lethal dose of radiation to a targeted area of cellular tissue. In those living with cancer, radiation leads to cellular death at the target site.

In this case, the remnants of cancerous tissues are removed from the body. Unfortunately, some healthy cells near the target area may also receive this dose of radiation.

Although technology has advanced light-years in terms of focusing radiation on a specific area, the destruction of healthy cells will naturally lead to an increase in fatigue.

For instance, radiotherapy for prostate cancer may result in fewer healthy cells affected than treatment on another area, such as the lungs.

Now, everyone responds to radiation therapy differently, and the exact type of cancer will affect your sense of tiredness as well. For example, if treatment destroys too many red blood cells, a person may develop anemia. Anemia, as a medical condition, is associated with increased fatigue. Meanwhile, larger cancers, requiring a prolonged dose of radiation, will lead to excessive tiredness too. In addition, the frequency of trips to receive radiotherapy may contribute to fatigue as well.

This goes back to the emotional toll of cancer treatment. The constant scheduling of appointments, visiting your oncologist, obtaining radiation treatment, taking chemotherapy and other treatment methods adds to the emotional toll. There will be days when going to the treatment center feels like too much to handle.

However, the tiredness is not a permanent aspect of your life. Some people have the fortune of not experiencing severe side effects of radiation therapy. As explained by the American Cancer Society, there is no sure-fire way to determine how extensive your side effects will be before launching treatment.

A thorough conversation with your radiotherapy care team can help you prepare for such side effects. He or she may be able to identify the primary source of your fatigue and help you find ways to alleviate your exhaustion. Before you meet with your doctor, you can prepare by considering these questions, which he or she will likely ask:.

People usually see a reduction in tiredness after several weeks of receiving a final treatment. If you get radiation therapy to the head or neck, you need to take good care of your teeth, gums, mouth, and throat.

Here are some tips that may help you manage mouth problems:. If these measures are not enough, ask your cancer care team for advice. Mouth dryness may be a problem even after treatment is over. If so, talk to your team about what you can do. Radiation treatment to your head and neck can increase your chances of getting cavities. This is especially true if you have dry mouth as a result of treatment.

Before starting radiation, talk to your cancer care team about whether you should get a complete check-up with your dentist. Ask your dentist to talk with your radiation doctor before you start treatment.

If you have one or more problem teeth, your dentist may suggest removing them before you start treatment. If you wear dentures, they may no longer fit well because of swollen gums. If your dentures cause sores, you may need to stop wearing them until your radiation therapy is done to keep sores from getting infected. Your dentist may want to see you during your radiation therapy to check your teeth, talk to you about caring for your mouth and teeth, and help you deal with any problems.

Most likely, you will be told to:. If you have radiation to the breast , it can affect your heart or lungs as well causing other side effects. To avoid irritating the skin around the breast, women should try to go without wearing a bra whenever they can.

If your shoulders feel stiff, ask your cancer care team about exercises to keep your shoulder moving freely. Breast soreness, color changes, and fluid build-up lymphedema will most likely go away a month or 2 after you finish radiation therapy. If fluid build-up continues to be a problem, ask your cancer care team what steps you can take. See Lymphedema for more information. Radiation therapy may cause long-term changes in the breast. Your skin may be slightly darker, and pores may be larger and more noticeable.

The skin may be more or less sensitive and feel thicker and firmer than it was before treatment. Sometimes the size of your breast changes — it may become larger because of fluid build-up or smaller because of scar tissue.

These side effects may last long after treatment. If you do see changes in breast size, shape, appearance, or texture after this time, tell your cancer care team about them right away. This is not as common today as it was in the past, because modern radiation therapy equipment allows doctors to better focus the radiation beams on the area with cancer, with less affect to other areas.

Rib fractures: In rare cases, radiation therapy may weaken the ribs, which could lead to a fracture. Be sure you understand what to look for and tell your cancer care team if you notice any of these side effects. Heart complications: Radiation to the breast can also affect the heart. It can cause hardening of the arteries which can make you more likely to have a heart attack later on , heart valve damage, or irregular heartbeats.

Lung damage radiation pneumonitis : Getting radiation to the breast can sometimes cause an inflammation of the lungs, which is called radiation pneumonitis. Damage to the nerves in the shoulder and arm: Radiation to the breast can sometimes damage some of the nerves to the arm. This is called brachial plexopathy and can lead to numbness, tingling, pain, and weakness in the shoulder, arm, and hand.

If your treatment includes brachytherapy internal radiation implants , you might notice breast tenderness, tightness, redness, and bruising. You may also have some of the same side effects that happen with external radiation treatment. Let your cancer care team know about any problems you notice. Getting radiation to the middle portion of the chest can raise your risk of heart disease. This risk increases with higher radiation doses and larger treatment areas in this part of your body.

Radiation can also cause hardening of the arteries which can make you more likely to have a heart attack later on , heart valve damage, or irregular heartbeats. Radiation pneumonitis is inflammation of the lungs that can be caused by radiation treatment to the chest or less often, the breast. It may occur about 3 to 6 months after getting radiation therapy. Common symptoms of radiation pneumonitis include:. Symptoms often go away on their own, but if treatment is needed, it is based on trying to decrease the inflammation.

Steroids, like prednisone, are usually used. With treatment, most people recover without any lasting effects. But if it persists, it can lead to pulmonary fibrosis stiffening or scarring of the lungs. Joining a cancer support group may also help. Talking to other people in a similar situation can often reduce feelings of isolation and stress. The cancer support charity Macmillan Cancer Support has a directory of support groups.

You can also call the free Macmillan support line: 00 00 every day, 8am to 8pm. Radiotherapy can damage your body's lymphatic system, which is a network of channels and glands that form part of your immune system the body's defence against illness. One of the jobs of the lymphatic system is to stop fluid building up in your body.

If it becomes damaged, you may experience pain and swelling. This is known as lymphoedema. It's most common in the arms or legs, but it can affect other areas, depending on the part of your body that was treated. It may be possible to reduce your risk of lymphoedema by looking after your skin and doing regular exercises.

Ask your care team if you're at risk and what you can do to help avoid it. If you do get it, treatment for lymphoedema can often help keep the symptoms under control. Radiotherapy can slightly increase your risk of developing another type of cancer in the years after treatment. But the chance of this happening is small, and the benefits of treatment generally outweigh the risk. Page last reviewed: 25 February Next review due: 25 February It's difficult to predict what side effects you'll get.

Sore skin In some people, radiotherapy can make the skin sore and red similar to sunburn , darker than normal or dry and itchy. This tends to start 1 to 2 weeks after treatment begins. They may suggest: washing your skin every day with mild, unperfumed soap patting your skin dry instead of rubbing it applying moisturiser to your skin every day not using perfume, perfumed soaps or talcum powder on the area not shaving the area if possible — if you need to shave, use an electric razor instead of wet shaving wearing loose-fitting clothes made of natural fibres, and avoid tight collars, ties or shoulder straps using a high-factor sunscreen SPF 30 or above to protect your skin from the sun not swimming in chlorinated water Skin problems usually settle within 2 to 4 weeks of treatment finishing, but sometimes your skin may stay slightly darker like it's tanned than it was before.

Tiredness Many people having radiotherapy feel tired fatigued a lot of the time or become tired very easily from doing everyday activities. It can help to: get plenty of rest avoid doing tasks or activities that you do not feel up to do light exercise, such as going for short walks, if you're able to — this can boost your energy level, but be careful not to push yourself too hard ask your friends and family for help with everyday tasks If you're working, you may want to ask your employer for time off or to let you work part-time until your treatment has finished.

Hair loss Hair loss is a common side effect of radiotherapy. Coping with hair loss Hair loss can be upsetting. Other options include headwear such as headscarves. Feeling sick Some people feel sick during, or for a short time after, radiotherapy treatment sessions. You should stop feeling sick soon after your treatment finishes.

Problems eating and drinking Radiotherapy can sometimes cause: a sore mouth loss of appetite and weight loss discomfort when swallowing Sore mouth Radiotherapy to your head or neck can make the lining of your mouth sore and irritated. Loss of appetite Feeling sick and tired during radiotherapy can make you lose your appetite, which could lead to weight loss.

Discomfort when swallowing Radiotherapy to your chest can irritate your food pipe oesophagus which can temporarily make swallowing uncomfortable. Swallowing problems usually improve after treatment stops. Diarrhoea Diarrhoea is a common side effect of radiotherapy to the tummy or pelvic area.

Stiff joints and muscles Radiotherapy can sometimes make your joints and muscles in the area being treated feel stiff, swollen and uncomfortable. Exercising and stretching regularly can help to prevent stiffness.

Sex and fertility issues Radiotherapy can have an effect on your sex life and fertility, especially if your lower tummy, pelvic area or groin is treated.