Chicago Health | Homepage
Why regular exercise helps reduce cancer risk

Why regular exercise helps reduce cancer risk

The Medicine Cabinet: Ask the Harvard Experts

By Howard LeWine, M.D.

Q: It makes sense that regular exercise helps prevent heart disease. But I have also read that it might help prevent cancer. What’s the reason?

A: Many studies show that people who are physically active are less likely to develop cancer. Such associations don’t prove that exercise prevents cancer. But there are also several potential biological explanations for a protective effect of regular exercise.

Adiposity. Fat tissue, especially abdominal fat, increases the levels of cytokines, insulin, and a variety of hormones that tend to promote cancer by, in part, spurring cell growth and turnover. It’s hard to fight the battle of the bulge with exercise alone, but in combination with a good, calorically prudent diet, exercise can help keep the pounds off.

Insulin levels. Insulin is the key hormone in blood sugar regulation. Insulin also acts a growth factor by turning on signals that stimulate cell growth. Physical activity helps the body use blood sugar more efficiently. Therefore the pancreas can release less insulin into the blood stream. Lower insulin levels may mean cancer cells get less stimulation to grow out of control.

Estrogen levels. Results from a large study of women called the Women’s Health Initiative showed that compared to women who get a lot of exercise, those who reported being sedentary had considerably higher levels of estrone, estradiol and free estradiol. They also had lower levels of sex-hormone-binding globulin, which by attaching to estradiol, makes it less available to target tissue. Results from other studies have shown that breast cancer risk is higher for postmenopausal women with high levels of various sorts of estrogen.

Inflammation. Studies have shown that high levels of inflammatory factors such as C-reactive protein and interleukin-6 have been linked to cancer. In some studies (but not all), exercise “cools off” the levels of these inflammatory factors as well as increasing the levels of adiponectin, a natural anti-inflammatory factor.

Immune function. Intense exercise can suppress the immune system, so some athletes are susceptible to colds and other upper respiratory functions. But in moderate amounts, exercise results in a stronger, more nimble immune system. How the immune system and cancer are related is complicated, but one hypothesis is that exercise makes the system’s natural killer cells more effective and they seem to play a role in tumor suppression.

(Howard LeWine, M.D., is an internist at Brigham and Women’s Hospital in Boston and assistant professor at Harvard Medical School. For additional consumer health information, please visit www.health.harvard.edu.)

(c) 2016 PRESIDENT AND FELLOWS OF HARVARD COLLEGE. ALL RIGHTS RESERVED. DISTRIBUTED BY TRIBUNE CONTENT AGENCY, LLC.

Similar Articles

Brain Boosts

Brain Boosts

Nourish Your Noggin with Lifestyle Changes By Laura Drucker Your brain needs to be well fueled, exercised and nurtured

Sneak in Fitness

Sneak in Fitness

Kick the sitting habit with exercises for body and soul Above photo: Mary Lou Cerami paddleboarding By

Count ingredients, not calories

Count ingredients, not calories

By Sharon Palmer, R.D.N. Shift your focus from the calories label to the ingredients label, and

Pneumonia a leading cause of hospitalization for children

Pneumonia a leading cause of hospitalization for children

What Doctors Know Source: U.S. Centers for Disease Control and Prevention Pneumonia puts thousands of young children

Cartilage repair, restoration becoming more common

Cartilage repair, restoration becoming more common

DEAR MAYO CLINIC: I recently heard about cartilage being used in knee joints. Last summer

Articles By Category

Family Health

In The Know

CH Lifestyle

September 2016
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
August 28, 2016 August 29, 2016 August 30, 2016 August 31, 2016 September 1, 2016 September 2, 2016 September 3, 2016
September 4, 2016 September 5, 2016 September 6, 2016 September 7, 2016 September 8, 2016 September 9, 2016 September 10, 2016
September 11, 2016 September 12, 2016 September 13, 2016 September 14, 2016 September 15, 2016 September 16, 2016 September 17, 2016
September 18, 2016 September 19, 2016 September 20, 2016 September 21, 2016 September 22, 2016 September 23, 2016 September 24, 2016
September 25, 2016 September 26, 2016 September 27, 2016 September 28, 2016 September 29, 2016 September 30, 2016 October 1, 2016

Categories

Recent Comments

Swing for the fences in the fight to Sideline Pancreatic Cancer

Swing for the fences in the fight to Sideline Pancreatic Cancer

Enjoy a great night of baseball at Peoples Natural

VIEW ARTICLE
Cost to give birth 1943 - Page 3 - Defending The Truth Political Forum

Cost to give birth 1943 - Page 3 - Defending The Truth Political Forum

A Hazy Shade of Healthcare: What does tort reform

VIEW ARTICLE

Archives