Regular, moderate exercise lowers the risk of developing at least seven types of cancer, from breast and colon to lymphoma and multiple myeloma, according to a review published in Journal of Clinical Oncologywhich pooled information from more than 750,000 adults in the United States, Europe and Australia, followed for an average of ten years.
For patients already diagnosed with colon cancer, an international study presented at the ASCO 2025 meeting shows that exercise programs under the guidance of a trainer, started after surgery and chemotherapy, reduced the risk of recurrence by 28% and the risk of death by 37%.
Active people have a lower risk of cancer
The most extensive research to date on the link between exercise and cancer has been carried out by the US National Cancer Institute. Researchers analyzed 12 prospective cohorts from the US and Europe with 1.44 million participants and published the results in JAMA Internal Medicine. The conclusion was that, among physically active people, the risk of developing 13 of the 26 types of cancer studied was considerably lower.
In an analysis later published in the Journal of Clinical Oncology, researchers separately looked at what happened to those who followed the standard recommendation for exercise, which is to practice two and a half to five hours of moderate activity per week. For these people, the results were encouraging:
- decreasing the risk of breast cancer by 6-10%,
- lowering the risk of colon cancer in men by 8-14%,
- decreasing the risk of endometrial cancer by 10-18%,
- decreasing the risk of kidney cancer by 11-17%,
- lowering the risk of liver cancer by 18-27%,
- decreasing the risk of lymphoma by 11-18% (in women),
- lowering the risk of multiple myeloma by 14-19%.
In addition, for several types of cancer, including breast, colon, endometrial, esophageal, and head and neck cancers, the benefit does not stop at the minimum recommended threshold. The higher the level of physical activity, the more the risk decreases, and the study does not show a clear threshold at which this effect would stabilize.
What actually happens in the body during exercise
For postmenopausal women between the ages of 50 and 75, regular exercise has the effect of lowering circulating estrogen levels. Lower exposure to this hormone throughout life translates into a lower risk of hormone-dependent breast cancer, the form most commonly seen after menopause.
Another randomized trial included men and women between the ages of 40 and 75, all with a recent normal colonoscopy. Some did an hour of aerobic exercise six times a week, the others continued their usual schedule. Active participants saw weight loss, lower levels of estrogenic hormones, and more importantly, cellular changes in the lining of the colon associated with a lower risk of colorectal cancer.
The movement works on several levels. First, it helps the body use insulin better and lowers the risk of long-term high insulin levels, a phenomenon associated with the development of breast and colon cancers. Physical activity reduces background inflammation in the body and strengthens the immune response, both of which are linked to lower cancer risk. It accelerates intestinal transit, so that the digestive mucosa spends less time in contact with possible carcinogens from food. And it prevents obesity, a risk factor for at least 13 types of cancer.
Most common cancers can be prevented by exercise
Of all the cancers studied, breast and colorectal have the most evidence. A meta-analysis published in the British Medical Bulletin pooled 38 studies involving more than 4 million women, of whom approximately 116,000 were diagnosed with breast cancer during follow-up. The most active women had a 12% lower risk compared to sedentary women, regardless of body mass index and regardless of whether they were pre- or post-menopausal.
In the Nurses' Health Study, an American cohort of over 95,000 participants followed for 20 years, nearly 4,800 cases of breast cancer were recorded. Postmenopausal women who briskly walked for about an hour a day had a 15% lower risk than sedentary women. An important result also emerged in participants who had been inactive before menopause but started exercising after. And in their case, the risk was 10% lower. In other words, starting later does not negate the benefits.
For colorectal cancer, one of the most cited sources is the NIH-AARP Diet and Health Study, which followed nearly 500,000 people over 50 years. More than 4,700 cases of colon or rectal cancer were registered during the study. In those who exercised at least five times a week, the risk of colon cancer was 21% lower in men and 15% lower in women. The same study found that men who spent nine hours or more a day sitting had a 60% higher risk of colon cancer than those who sat for less than three hours.
Physical activity can also be helpful after diagnosis
A meta-analysis published in 2025 in the journal GeroScience, which included 151 cohorts with nearly 1.5 million cancer patients, looked at the effects of movement after diagnosis on survival. For all five types of cancer included, mortality decreased as follows: by 31% in the case of breast cancer, by 27% in prostate cancer, by 29% in colorectal cancer, and by 24% in the case of lung cancer.
Similar results appeared in a randomized clinical trial, considered the gold standard in medicine. The CHALLENGE international study, presented in 2025 at the American Society of Clinical Oncology congress, divided 889 patients with stage III or stage II high-risk colon cancer into two groups: some exercised under the supervision of a trainer, the others only received leaflets about sports and healthy eating.
After a median follow-up of almost eight years, 93 patients in the exercise group had a single relapse, compared with 131 in the control group. At five years, the disease-free survival rate was 80% and 74%, respectively. The risk of recurrence or the appearance of a new cancer decreased by 28%. At eight years, overall survival had reached 90% in the active group, compared to 83% in those who received only the informational materials. The risk of death was 37% lower in patients who exercised.
“After surgery and chemotherapy are completed, approximately 30% of high-risk stage II and stage III colon cancer patients will eventually have a recurrence of the disease. As oncologists, one of the most common questions we receive from patients is 'what else can I do to improve the prognosis?'” These results now give us a clear answer: an exercise program that includes a personal trainer will reduce the risk of recurrence or another cancer, it will make you feel better and help you live longer,” said lead study author Christopher Booth, an oncologist at Queen's University in Kingston, Canada.
How much movement is needed and at what intensity
The American Cancer Society recommends 150-300 minutes of moderate exercise (brisk walking or cycling under 10 mph) per week or, alternatively, 75-150 minutes of vigorous activity (running, cycling over 10 mph, strength training). The two can also be combined. The World Health Organization proposes a similar threshold: at least 150 minutes of moderate activity per week for adults.
The important part is that the benefits don't just come from prolonged effort. Even short bouts of vigorous activity have been associated with reductions in the risk of developing breast, colon, bladder, esophageal, stomach, or endometrial cancers.
There is also good news for those who fail to exercise daily. A study of almost 89,000 participants from the UK Biobank, published in Scientific Reports, shows that the so-called “weekend warrior” model, in which the recommended 150 minutes per week of physical activity is done in one or two sessions, was associated with a 40% lower risk of kidney cancer compared to no physical activity.
From theory to practice: what alert walking means
One aspect that researchers keep coming back to is that exercise does not necessarily mean intense training in the gym. Half an hour of brisk walking, five days a week, already reaches the minimum recommended threshold. Taking the stairs instead of taking the elevator, gardening, taking active breaks during the workday, dancing or playing energetically with children also fall into the category of moderate physical activity.
Brisk walking can be assessed by speed – over 3 miles per hour, according to the CDC, or by steps per minute: 100-120. Basically, for walking to be considered effective physical activity, you should be able to talk, but not sing. At the same time, during vigorous activity you should not be able to say more than a few words without pausing for breath.
For cancer patients undergoing treatment, oncologists recommend short sessions, adapted to individual tolerance, under medical supervision, especially during periods of chemotherapy or radiotherapy. A single workout was associated, in a smaller study, with a temporary slowing of cancer cell growth. Even a few minutes a day count, and the effect seems to add up.
