By: Ergolog

Every time you do intensive exercise, your body produces substances that kill cancer cells. The effect of a single session is limited, but the effect of a lifestyle that has included intensive exercise several times a week for years on end is probably considerable. Sports scientists at the University of Copenhagen discovered this.

Study 1

The researchers performed experiments with blood samples taken from women who were being treated for breast cancer. The women did an intensive training session that included strength and cardio training once a week over a six-month period. Before the training started and a few days after the last training session at the end of the six months the researchers took blood samples from the participants.

They then added estradiol sensitive breast cancer cells [MCF-7] and hormone sensitive breast cancer cells [MDA-MB-231] to the blood samples. The cells grew equally in both blood samples.

Study 2

The researchers got one group of women to do fitness training under supervision, doing both strength training and cardio training. Blood samples were taken before the workout and afterwards, and then MCF-7 and MDA-MB-231 cells were added to the samples.

The viability of both types of cells decreased in the blood samples taken just after the workout had been completed.

The concentrations of adrenalin, noradrenalin and interleukine-6 [Il-6] were much higher in the blood that had been taken just after the workout. In addition, the researchers also observed that the concentrations of interleukine-8 [Il-8] and TNF-alpha were also higher.

Adrenalin and noradrenalin are pep hormones; Il-6, Il-8 and TNF-alpha are inflammatory factors. It’s not healthy to have inflammatory factors continuously circulating in your body, but temporary peaks help the immune system to repair damaged tissue and to attack pathogens and cancer cells.


“Here, we present data from ‘real-life’ clinical rehabilitation settings, demonstrating that systemic changes, occurring immediately during performance of a 2 h exercise bout, have inhibitory effects on breast cancer viability in the two tested breast cancer cell lines,” the Danes summarised. “Contrary, systemic adaptations to 6 months of training did not translate into enhanced breast cancer control.”

“With this, we propose that the acute transient changes in humoral factors during each exercise bout drive the positive effects of exercise on breast cancer outcome, rather than the systemic adaptations seen with training over time.”

“Accordingly, future research should focus on detailed characterization of these systemic changes occurring during acute exercise, aiming to identify potential exercise-induced anti-oncogenic factors and to establish how these are regulated by different modes of exercise.”

Breast Cancer Res Treat. 2016 Oct;159(3):469-79.