An intensive workout may help destroy cancer cells

EXERCISE guidelines for cancer patients may need to be revised after it was found that intensive physical activity can help shrink tumours.

Experts have recommended for some time that exercise is beneficial for those with cancer, around two million people in the UK.

Now researchers have found how adrenaline – which is released during a higher intensity exercise – helps the body’s own defences destroy cancerous tumours.

While the study involved mice, researchers suggest that higher intensity workouts may benefit cancer patients, although more research is needed.

Scientists found mice who spent time running on an exercise wheel shrank their tumours by 50 per cent compared to those who were less active.

As a test, some inactive mice were injected with adrenaline to mimic the effect of exercise, with similar beneficial results.

‘Natural killer’ cells were directed towards tumours via the bloodstream both during vigorous exercise and after the adrenaline injection, the study published in Cell Metabolism found. Researchers believe that the shot of adrenaline produced by a high-intensity workout helps move cancerkilling cells towards lung, liver, or skin tumours in the mice.

Dr Pernille Hojman, of the University of Copenhagen, said: ‘It is known that infiltration of natural killer immune cells can control and regulate the size of tumours, but nobody had looked at how exercise regulates the system.

‘While it has previously been difficult to advise people about the intensity at which they should exercise, our data suggest that it might be beneficial to exercise at a somewhat high intensity in order to provoke a good adrenaline surge and hence recruitment of natural killer cells.’ The researchers also found that a chemical signal produced by muscles during exercise, Interleukin 6, helps activate and guide natural killer cells towards tumour cells.

Healthy adults are recommended to do 150 minutes of moderate intensity exercise a week. Macmillan Cancer Care says cancer patients who cannot do this should be as active as their condition allows.