Key messages
- Compared to no yoga, yoga after anticancer therapy probably reduces cancer-related fatigue slightly in the short term (up to 12 weeks after doing yoga).
- We do not know if yoga during anticancer therapy relieves short-, medium-, or long-term cancer-related fatigue compared to no yoga.
- More research is needed to understand (1) if the effects of starting yoga after anticancer therapy persist beyond 12 weeks, and (2) what are the effects of doing yoga before starting and during cancer treatment.
What is cancer-related fatigue?
Cancer-related fatigue is a feeling of extreme tiredness that lasts for a long time. It can be caused by cancer, cancer therapy, or both. Cancer-related fatigue affects the body and mood, and makes it hard to perform regular activities. It is stronger than just being tired, and does not go away by resting.
How is cancer-related fatigue treated?
Clinical guidelines (documents that give healthcare professionals advice on the best ways to care for people, based on the latest research and expert opinion) recommend physical exercise to improve cancer-related fatigue. Physical exercise affects cancer-related fatigue by influencing biological and psychological processes. But it is unclear what types of exercise may be most beneficial. It is thought that yoga may reduce cancer-related fatigue and improve the quality of life of people with cancer because of how yoga combines physical exercise/movement with breath control, mental focus, and body awareness. This review is one of a suite of five reviews exploring different kinds of exercise for cancer-related fatigue.
What did we want to find out?
We wanted to find out if yoga improves cancer-related fatigue and quality of life in adults (18 years and older). We also wanted to learn if there were any adverse events in the studies; that is, unwanted events that caused harm to participants.
We investigated the effects of yoga in the short term (up to 12 weeks after doing yoga sessions), medium term (between 12 weeks and 6 months after), and long term (more than 6 months after doing yoga sessions).
What did we do?
We searched for studies that compared yoga with no yoga in adults with any cancer. We included yoga done before, during, or after initiation of anticancer therapy. We included multiple types of yoga, including Hatha (a gentle, slow yoga focusing on basic poses and breathing) and Dru yoga (a flowing style that includes movements, breathing, and relaxation).
We compared and summarised the results of the studies, and rated our confidence in the evidence, based on factors such as study methods and sizes. We also explored whether the type of yoga, type of cancer, exercise format (individual versus group-based yoga; supervised or unsupervised), and participant age made any difference to the results.
What did we find?
We found 21 studies involving 2041 participants with various cancers. Most were women with breast cancer. Yoga was started during anticancer therapy in 13 studies and after therapy in eight studies. We did not find any studies in which participants practised yoga before anticancer treatment.
Yoga during anticancer therapy
It is unclear if yoga during anticancer therapy has an effect on short-, medium-, or long-term cancer-related fatigue compared to no yoga.
Yoga during anticancer therapy may increase short- and medium-term quality of life compared to no yoga, but we are very uncertain about the results. None of the studies measured long-term quality of life.
We do not know if doing yoga or not during anticancer therapy leads to adverse events. Only one study reported this outcome, meaning the evidence was weak/limited.
We did not find differences in the effects of different types of yoga, group and individual training, or supervised and unsupervised training.
Yoga after anticancer therapy
Yoga after anticancer treatment probably reduces short-term cancer-related fatigue compared to no yoga. We do not know if yoga after anticancer therapy reduces medium-term cancer-related fatigue. None of the studies measured long-term cancer-related fatigue.
Yoga after anticancer therapy may increase short- and medium-term quality of life slightly, but we are very uncertain about the results. None of the studies measured long-term quality of life.
We do not know if doing yoga after anticancer therapy leads to any adverse events.
We did not find differences in the effects of different types of yoga, types of cancer, or between age groups.
What are the limitations of the evidence?
The people in the studies were aware of which treatment they were getting – yoga or no yoga. Although this is inevitable for this type of research, it could have influenced the results. For some effects (e.g. medium-term and long-term effects), we did not find studies large enough to be certain about our results. Therefore, more research is needed to understand how sustainable the effects of yoga are for cancer-related fatigue, quality of life, and adverse events.
How current is this evidence?
The evidence is current to October 2023.