Here’s Why Exercise is Crucial in Preventing, Treating Cancer

Strength training two to three times a week along with aerobic exercise three times a week is recommended for cancer prevention. Getty Images
  • A panel of experts has released guidelines stating that regular exercise can help prevent cancer as well as help people undergoing cancer treatment.
  • The experts recommend 30 minutes of aerobic exercise 3 times a week and strength training 2 to 3 times a week.
  • Experts say exercise can help prevent cancer by reducing inflammation, keeping weight under control, and boosting the immune system.

Kathryn Schmitz is seeking a paradigm shift.

Schmitz, a professor of public health specializing in cancer at Penn State University, thinks the perception of the ties between exercise and cancer is where the perception of the ties between exercise and heart health was decades ago.

Back then, she said, getting a patient out of bed and moving after a heart attack would be criticized. Today, the benefits of exercise to heart health and recovery are well known.

A similar consensus is emerging in the way the medical field thinks about cancer.

The latest sign in that shift came this week, with the publication of new guidelines that recommend physicians “prescribe” exercise in efforts to reduce the risk of certain cancers and improve the treatment outcomes and quality of life of those with the disease.

“Today if you asked someone with a dad with colon cancer if he should be exercising they’d probably either say no or they don’t know,” Schmitz told Healthline.

Schmitz co-chaired the roundtable — which included experts from the American College of Sports Medicine, the American Cancer Society, and 15 other groups — that put together the new guidance.

The gist of the guidance, published in three papers this week, is that exercise can contribute to the prevention of bladder, breast, colon, esophagus, kidney, stomach, and uterine cancer.

The guidelines also state exercise can help improve survival rates for people with breast, colon, and prostate cancer — as well as the quality of life of those people in terms of reducing side effects of cancer treatment.

How much exercise?

The researchers recommend that people with cancer do 30 minutes of moderate aerobic activity 3 times a week and strength training such as weights 2 to 3 times a week.

Schmitz said originally the researchers looking into that question sought to find out if there were specific “doses” of exercise that could be tailored to different people with cancer.

But the 30 minutes 3 times a week recommendation seemed to work pretty universally.

They still ended up with their goal of being able to “prescribe exercise like a drug,” Schmitz said. “Just turns out that it’s, say, 600 milligrams for everybody, if you will.”

In terms of cancer prevention, the recommended general physical activity guidelines are at least 150 minutes of moderate exercise or 75 minutes of vigorous exercise a week.

Schmitz says getting more tailored recommendations for cancer prevention is one of the remaining open questions that ongoing research hopes to help answer.

“We don’t know the exact, optimal dose of exercise needed for cancer prevention,” Alpa Patel, the American Cancer Society’s senior scientific director for epidemiology research, told Healthline. “But we know from the evidence to date that the more you do the better.”

Why exercise works

Patel, lead author of the paper that covered the prevention aspects of the new guidance, said how exactly exercise affects cancer prevention is severalfold.

That includes exercise’s effects on reducing inflammation, helping regulate blood sugar and sex hormones, and improving metabolism and immune function.

“Depending on the specific cancer, one or more of those mechanisms may be more important than the others,” he said. “So, for breast cancer, the benefits of exercise are really driven through the impact on sex hormones.”

“It can also affect cancer development or risk through reducing obesity, a risk factor for many cancers,” said Dr. Crystal Denlinger, an oncologist at the Fox Chase Cancer Center in Philadelphia and chair of the National Comprehensive Cancer Network’s panel on survivorship guidelines.

She told Healthline that the exact reasons why exercise affects certain cancers in different ways still needs additional research.

The current recommendations do vary a bit based on personal history, Denlinger noted. But, she said, “at this time, there is no one ‘best’ exercise — anything that gets you moving and active is good.”

She said further trials are under way to evaluate how and when exercise can affect cancer treatment.

The effort underway for Schmitz — through an initiative she started at the American College of Sports Medicine — is pushing to get oncologists to assess and advise cancer patients’ physical activity.

“This is an easy, cheap way to give patients less fatigue and a better quality of life,” she said.