New research from the Karolinska Institutet in Sweden, has established why people who exercise when suffering from cancer generally have better outcomes

Cancer sufferers who exercise regularly have a generally better prognosis than inactive patients, but science hadn’t managed to agree why that is, up to this point.

However, researchers at Karolinska Institutet in Sweden have found a likely explanation of why exercise helps slow down cancer growth.

Randall Johnson, professor at the department of cell and molecular biology at the Karolinska Institutet, says new evidence points to physical activity changing the metabolism of the immune system’s cytotoxic T cells, thereby improving their ability to attack cancer cells.

Johnson is the author of a study – Cytotoxic T-cells mediate exercise-induced reductions in tumor growth – which makes the connection. The work was published in the journal eLife.

“The biology behind the positive effects of exercise can provide new insights into how the body maintains health, as well as helping us design and improve treatments against cancer,” said Johnson.

To examine how exercise influences cancer growth, researchers observed two groups of mice – one which exercised regularly and a another that remained inactive.

T cell activation
They measured levels of common metabolites that are produced in muscle at high levels during exertion.

Some of these metabolites, such as lactate, altered the metabolism of the T cells and increased their activity.

The researchers also found that T cells in the exercising group showed an altered metabolism when compared to T cells from the sedentary group.

During the study, it became clear that cancer cell growth slowed and mortality decreased in the trained group, when compared with the results for the untrained group.

The impact of exercise
Helene Rundqvist, the study’s first author and senior researcher at the department of laboratory medicine at the Karolinska Institutet, said: “Our research shows that exercise affects the production of several molecules and metabolites that activate cancer-fighting immune cells and thereby inhibit cancer growth.

“We hope these results contribute to a deeper understanding of how our lifestyle impacts our immune system and that this work informs the development of new immunotherapies against cancer.”

Find out more about this research at: www.HCMmag.com/TCELLS