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How Does Exercise Reduce Cancer Risk?

How Does Exercise Reduce Cancer Risk?

Someone who is physically active has a lower risk of developing many types of cancer. But, how exactly does exercise reduce cancer risk? Find out here.

CAUTION: Know the Signs and Symptoms of Cancer

Regular exercise reduces cancer risk, a study finds

A new study from the National Cancer Institute concluded that regular exercise lowers the risk of many types of cancer.

The research, which is now published in JAMA Internal Medicine, reviewed 12 extensive studies with over 1.4 million participants. The investigators then pooled the subjects’ details, such as their physical activity and the diseases they developed, which include 190,000 cancer cases.

Afterward, the researchers compared the study participants’ rates of cancer with their levels of physical activity. Results show that compared to the least active participants, the most active subjects have 7% to 38% lower rates of the following cancers:

  • Kidney
  • Lung
  • Colon
  • Esophagus
  • Head
  • Neck
  • Bladder
  • Rectum
  • Breast
  • Myeloma
  • Myeloid leukemia

Many experts believe that this carefully conducted study with over a million participants further supports the theory that performing regular exercise lowers the risk of cancer.

Although the study did not answer the question, how does exercise reduce cancer risk?, medical experts have some theories. According to them, being physically active lowers the risk of cancer because:

It regulates our hormonal levels

One of the possible reasons why regular exercise lowers the risk of cancer is that it controls the production of hormones in the body.

You see, some hormones, when produced excessively, encourage our cells to multiply out of control. This uncontrolled cellular multiplication leads to the occurrence of tumors.

For instance, high levels of the hormone estrogen cause the unnecessary multiplication of the breast cells, which can result in breast cancer. Too much insulin can also promote tumor growth.

According to reports, performing regular exercise can lower our estrogen levels and improve our insulin sensitivity.

It improves our bowel movement

Did you know that poor bowel movement can contribute to the increased risk of developing colon cancer?

The more time the waste products stay in the large intestine, the more our digestive tract is exposed to cancer-causing agents (carcinogens).

Physical activity helps move waste quickly along the colon, which reduces its exposure to carcinogens.

It promotes healthy weight

Does exercise reduce cancer risk because it promotes healthy weight? Experts highlight that, yes, it does.

Various medical studies indicate that excess body fat may increase cancer risk by affecting:

  • The body’s inflammatory response
  • Cell and blood vessel growth
  • How a cell can survive longer than normal
  • The cells’ ability to spread to other parts of the body (metastasis)

Moreover, the American Cancer Society pointed out that excess body weight can be responsible for about 5% of cancers in men and 11% in women in the US alone. Being overweight and obese can also be responsible for about 7% of cancer deaths.

Since exercise helps promote healthy weight, doctors emphasize that it can also reduce cancer risk.

It boosts our immune system

Finally, since exercise boosts the immune system, it can also reduce our cancer risk.

In a research paper or study titled, Exercise could fortify the immune system against future cancers, the investigators analyzed the relationship between physical activity and immunity. They worked with 16 cancer survivors, all of whom, save for one, recently finished chemotherapy.

  • At the start of the clinical study, they took blood samples from the subjects and checked their T cell levels.
  • T cells are specialized cells that are capable of fighting infections as well as cancer cells.
  • Previous trials already identified that cancer survivors often have “senescent” T cells, which means that their T cells are no longer as effective as before in fighting infections and cancer.

According to study leader Laura Bilek, if the cancer survivors can build a population of healthy, capable T cells (naïve), they have a better chance of regaining a normal immune system and cancer-fighting ability.

  • To find out if exercise helps build naïve T cells, Bilek and her team enrolled the participants in a 12-week exercise program.
  • At the end of the program, the researchers took another set of blood samples from the study subjects to see if there are changes in their T cells.
  • Surprisingly, the ratio between senescent and naïve T cells changed favorably in most cancer survivors – the majority of them gained more naïve T cells.

With these results, the study suggests that exercise can get rid of unhelpful T cells and make room for the more effective, naïve variety. This can help avoid secondary cancers in survivors; it may also reduce the chance of cancer for those who never had it.

Health Habits That Can Lower Your Risk of Cancer

What does it mean to be physically active?

According to experts, we don’t have to be a marathon runner to be called “physically active.” The idea is to ensure that we perform 150 minutes of moderate-intensity exercise or 75 minutes of vigorous workouts per week. You can get this level of physical activity by walking for 30 minutes daily for 5 days weekly.

If you’re looking for ways to get back in shape, you can head over to this article.

Key Takeaways

How does exercise reduce cancer risk? Studies show physical activity can lower our risk of cancer by regulating hormones, improving bowel movement, promoting a healthy weight, and boosting our immune system.

Learn more about Cancer here.

Hello Health Group does not provide medical advice, diagnosis or treatment.


Does regular exercise reduce cancer risk?
Accessed November 6, 2020

Does Body Weight Affect Cancer Risk?
Accessed November 6, 2020

Exercise could fortify immune system against future cancers
Accessed November 6, 2020

Be physically active
Accessed November 6, 2020

Exercise Linked With Lower Risk of 13 Types of Cancer
Accessed November 6, 2020

Physical Activity and Cancer
Accessed November 6, 2020

What are the benefits of exercise?
Accessed November 6, 2020

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Written by Lorraine Bunag, R.N. Updated May 30
Medically reviewed by John Paul Ferolino Abrina, M.D.