Fatigue, the most common side effect of cancer treatment, is not the same as casual or sleep-deprived tiredness, because it cannot be relieved with simple sleep and rest. Cancer-related fatigue affects approximately 94% of cancer survivors and is a sense of heaviness, of not having the energy to be able to get up and go.
Research has shown that it is a troubling, lingering side effect for many long-term survivors. Long-term cancer survivor fatigue is under-reported, underdiagnosed, and undertreated. Studies have suggested that fatigue levels are higher in cancer survivors than in the standard population, even as long as 5 years after completion of treatment. 
Physical fatigue leads to mental fatigue and to mood changes. Cancer-related fatigue can be caused by treatment with chemotherapy or radiation, anemia, abnormal hormone levels, stress, and medications that cause drowsiness, among other possible causes. 
Treatment for fatigue involves a multidisciplinary approach to manage the underlying causes. Doctors will conduct an assessment, which will include a physical exam, rating of the level of fatigue, verifying symptoms and side effects of treatment and medications, and blood tests to detect anemia and possible infections. 
Evidence indicates that lower volumes and intensities of exercise appear to be most effective in addressing symptoms of fatigue during chemotherapy.  Other treatment options include treating anemia, infections, and/or depression which could be causing fatigue. Certain drugs and dietary supplements are also being studied as treatment options. 
There are some steps that you can take to deal with cancer related fatigue:
- Conserve and maintain your energy. It is important to prioritize and do the things that are most important when you are feeling the best. Nutrition and hydration are very important and contribute to keeping your energy levels up.
- You should rest frequently throughout the day. Taking naps during the day can help relieve some of your fatigue.
- Exercise lightly when you feel up to it. Going for a short walk or enjoying a bit of gardening are some of the activities that can add energy to a fatigued body.
The causes of fatigue after treatment ends are different than the causes of fatigue during treatment, and so the treatment of fatigue will be different depending on if it is occurring during or after treatment. Since fatigue can greatly affect quality of life of cancer survivors, long-term follow-up is important. 
Most importantly, speak up if your fatigue is causing problems in day-to-day life. Don’t assume that it’s just part of the cancer survivor experience. Talk to your doctor about possible causes, so you can work together to improve them and try to remedy the issue.
The Untire app could be a valuable resource for cancer patients and survivors struggling with cancer-related fatigue. This can include both mental and physical exhaustion. Untire is a free app, available on the App Store and Google Play Store. It was developed based on proven methods and interventions, and includes easy-to-use videos, tutorials, and daily tips. It also integrates an online support community, where you can connect with others who are sharing a similar experience.
 Dr. Margaret L. McNeely, Physiotherapist. Presentation on rehabilitative services in Alberta. Presented at the All-party Cancer Caucus Meeting May 8th, 2018.