Key messages

• Cardiovascular training during anticancer therapy probably reduces cancer-related fatigue slightly for up to 12 weeks.

• The longer-term effects of cardiovascular training on cancer-related fatigue and quality of life are uncertain and there is no evidence about the effects of cardiovascular training before anticancer therapy.

• We found nearly 50 studies of cardiovascular training before, during, and after cancer treatment that are underway and these will add to the evidence when the results are published.

What is cancer-related fatigue?

Cancer-related fatigue is an extreme feeling of tiredness over a long period of time. It can be caused by cancer treatment or the cancer itself. It is the most common symptom among people with cancer. It cannot be relieved by rest, and it affects the body and mind.

What is cardiovascular training?

Cardiovascular training is any activity that uses the large muscle groups of the buttocks and thighs, and increases heart and breathing rate. Examples are walking, running, cycling, and swimming.

Why is cardiovascular training possibly effective for cancer-related fatigue?

Cancer-related fatigue is linked to the body's response to cytokines, which regulate how tissues and organs increase in size (called cell growth). Cancer or cancer therapy may produce proteins called pro-inflammatory cytokines, which cause or worsen inflammation (the body's response to an injury or illness, which includes symptoms such as swelling and pain). Cardiovascular training can help reduce inflammation.

What did we want to find out?

We wanted to know whether cardiovascular training reduces cancer-related fatigue compared to no training. We explored the effects at short (up to 12 weeks), medium (up to six months), and long term (longer than six months). We also looked at quality of life, unwanted effects, anxiety, and depression.

What did we do?

We searched for studies that investigated cardiovascular training before, during, or after anticancer therapy compared to no training. These studies needed to evaluate cancer-related fatigue or quality of life, or both. The cardiovascular training had to have at least five sessions of exercise and had to be given by face-to-face instruction (either by video or in person). We did not consider studies with fewer than 20 people per group, or that were available in a short summary form only.

What did we find?

We found 23 studies with 2135 people. Most studies were conducted in high-income countries (97%; where people have easy access to good-quality health care). A total of 1101 people received cardiovascular training and 1034 people received no training. The people included in the studies were mostly female and had breast cancer.

We also found 36 ongoing studies, and 12 completed studies that have yet to be published.

Main results

There were no studies comparing cardiovascular training before anticancer therapy to no training. We included 10 studies for cardiovascular training during anticancer therapy, but could only use the results of eight. For cardiovascular training after anticancer therapy versus no training, we found 13 studies for inclusion, but could only use the results of nine.

Cardiovascular training during anticancer therapy versus no training:

• probably reduces short-term cancer-related fatigue slightly (6 studies, 593 people);

• probably results in little to no difference in short-term quality of life (6 studies, 612 people);

• we do not know if cardiovascular training increases or decreases medium- and long-term cancer-related fatigue and quality of life, and any unwanted effects.

Cardiovascular training after anticancer therapy versus no training:

• we do not know if cardiovascular training increases or decreases short- and long-term cancer-related fatigue and quality of life, and any unwanted effects;

• we could not find any data for medium-term cancer-related fatigue and quality of life.

What are the limitations of the evidence?

We are moderately confident in the evidence about the effect of cardiovascular training during anticancer therapy on short-term cancer-related fatigue and quality of life. Our confidence in the other evidence is very low as there were fewer or smaller studies, and people knew which treatment they received. There was no evidence for cardiovascular training before anticancer therapy and for cardiovascular training after anticancer therapy on medium-term cancer-related fatigue and quality of life.

How up to date is this evidence?

Our evidence is up to date to 16 October 2023.