Exercising muscles pumps out substances that can suppress the growth of breast cancer cells, according to an important new study of exercise and cancer. The study, published last month, involved 32 women who had survived breast cancer. Past research indicates that exercise helps some cancer survivors avoid recurrence of their disease. So, for the new study, Professor Newton and his colleagues recruited women who had finished treatment for breast cancer. “Our group, and others, have shown that tailored, progressive exercise training programmes that include high-intensity interval training are both safe and beneficial” for breast cancer survivors.