Regular exercise could help to halt the progression of cancer cells, new research has shown.
The findings of a recent study were presented at The Physiological Society’s Annual Conference, Physiology 2021. The research shows that molecules released into the bloodstream during exercise (such as small proteins) can act directly on bowel cancer cells to slow down their growth.
Previous studies have demonstrated that regular physical activity reduces the risk of developing bowel cancer – which is thought to happen because physical activity can help individuals maintain a healthy body weight. However, the new findings suggest that being physically active could reduce the risk of bowel cancer regardless of weight loss.
Researchers studied 16 male participants who had lifestyle risk factors for bowel cancer (all participants were 50 years old or older, were overweight or obese, and did not regularly exercise). They collected blood samples from participants before and after 45 minutes of ‘moderate’ intensity indoor cycling, and before and after a non-exercise ‘control’ experiment. The researchers assessed whether exercise altered the concentration of specific proteins in the blood. Finally, they added the liquid portion of each blood sample that contains the proteins (known as serum) to bowel cancer cells in a laboratory and monitored cancer cell growth over 48 hours.
Though the findings are preliminary and do have limitations, they provide a clearer understanding of the mechanisms linking physical activity and cancer risk. This will help to inform the development of effective exercise programmes for preventing cancer development. Additionally, the knowledge could also aid in the development of drugs that can mimic some of the benefits of exercise.
Limitations and future research
Researchers note that the main limitation of the research is that the cancer cells were grown in a dish under tightly-controlled laboratory conditions. Cancer tumours in humans are more complex and interact with the environment around them, such as surrounding blood vessels and immune cells. This means that the findings may not necessarily apply to real-life cancer tumours.
Dr Sam Orange, the presenter and lead author of this research, said: “Following on from this research, we want to understand a few more things, including which specific molecules in the blood are responsible for reducing the growth of the bowel cancer cells, and whether exercise performed at a high intensity has a more pronounced effect on bowel cancer cell growth than exercise performed at a moderate intensity.”