Guidelines for Physical Activity for Cancer Prevention

Cancer is the second leading cause of death in the United States, behind only heart disease. People with cancer also often experience physical effects (from the cancer itself and from treatment), distress, and a lower quality of life. Quality of life can also be affected for family members, caregivers, and friends of people with cancer.

For most Americans who do not use tobacco, the most important cancer risk factors that can be changed are body weight, diet, and physical activity. At least 18% of all cancers diagnosed in the US are related to excess body weight, physical inactivity, excess alcohol consumption, and/or poor nutrition, and thus could be prevented.

Along with avoiding tobacco products, staying at a healthy weight, staying active throughout life, and eating a healthy diet may greatly reduce a person's lifetime risk of developing or dying from cancer. These same behaviors are also linked with a lower risk of developing heart disease and diabetes.

Although these healthy choices can be made by each of us, they can be helped or slowed by the social, physical, economic, and regulatory environment in which we live. Community efforts are needed to create an environment that makes it easier for us to make healthy choices when it comes to diet and physical activity.

At least 18% of all cancers and about 16% of cancer deaths in the US are related to excess body weight, physical inactivity, alcohol consumption, and/or poor nutrition. Many of these cancers could potentially be prevented by following the ACS recommendations on nutrition and physical activity.

RECOMMENDATIONS FOR A HEALTHY LIFE:

Achieve and maintain a healthy weight throughout life.

• Keep your weight within the healthy range, and avoid weight gain in adult life.
• Be physically active.
• Adults: Get 150-300 minutes of moderate-intensity or 75-150 minutes of vigorous-intensity activity each week (or a combination of these). Getting to or exceeding the upper limit of 300 minutes is ideal.
• Children and teens: Get at least 1 hour of moderate or vigorous intensity activity each day.
• Limit sedentary behavior such as sitting, lying down, watching TV, and other forms of screen-based entertainment.

Follow a healthy eating pattern at all ages.

• A healthy eating pattern includes:
  • Foods that are high in nutrients in amounts that help you get to and stay at a healthy body weight
  • A variety of vegetables – dark green, red, and orange, fiber-rich legumes (beans and peas), and others
  • Fruits, especially whole fruits in a variety of colors
  • Whole grains
• A healthy eating pattern limits or does not include:
  • Red and processed meats
  • Sugar-sweetened beverages
  • Highly processed foods and refined grain products

It is best not to drink alcohol.

• People who do choose to drink alcohol should have no more than 1 drink per day for women or 2 drinks per day for men.

BODY WEIGHT AND CANCER RISKS

Being overweight or obese is clearly linked with an increased risk of several types of cancer, including:

• Breast cancer (among women who have gone through menopause)
• Colon and rectal cancer
• Endometrial cancer (cancer in the lining of the uterus)
• Esophagus cancer
• Kidney cancer
• Liver cancer
• Ovarian cancer
• Pancreas cancer
• Stomach cancer
• Thyroid cancer
• Multiple myeloma
• Meningioma (a tumor of the lining of the brain and spinal cord)

Being overweight or obese might also raise the risk of other cancers, such as:

• Non-Hodgkin lymphoma
• Male breast cancer
• Cancers of the mouth, throat, and voice box
• Aggressive forms of prostate cancer

Being overweight or obese is largely the result of taking in too many calories (from both food and beverages) and not burning enough calories, although a person’s genes and changes in their metabolism as they age are also factors.

• The dietary factors most often linked with excess body fat include sugar-sweetened beverages, fast foods, and “Western type” diets (diets high in added sugars, meat, and fat), whereas foods containing fiber and “Mediterranean” diet patterns may reduce risk.
• Aerobic physical activity, including walking, is linked with a lower risk of excess body weight, whereas sedentary behaviors (sitting and lying down) and more screen time (such as looking at a phone or computer, or watching TV) is linked with a higher risk.

BENEFITS OF PHYSICAL ACTIVITY

Physical activity has been linked to a lower risk of several types of cancer, including:

• Colon cancer (for which the link is strongest)
• Breast cancer
• Endometrial cancer (cancer in the lining of the uterus)
• Bladder cancer
• Esophagus cancer
• Stomach cancer

Physical activity might also affect the risk of other cancers, such as:

• Lung cancer
• Head and neck cancers
• Liver cancer
• Pancreas cancer
• Prostate cancer
• Ovarian cancer

Being active may also help to prevent weight gain and obesity, which may, in turn, reduce the risk of developing cancers that have been linked to excess body weight.

A physically active lifestyle may also lower a person's risk of other health problems such as heart disease, high blood pressure, diabetes, and osteoporosis (bone thinning).

Some studies have shown a link between weight loss and a lower risk of some types of cancer, such as breast cancer after menopause and endometrial cancer. The risk of some other cancers may also be lowered by weight loss. While there is still much to be learned about this area, people who are overweight or obese are encouraged to lose weight.

Excess body weight is thought to be responsible for about 11% of cancers in women and about 5% of cancers in men the United States.

The link to body weight is stronger for some cancers than for others. For example, excess body weight is thought to be a factor in more than half of all endometrial cancers, whereas it is linked to a smaller portion of other cancers.

Clearly, excess body weight is a major risk factor for many cancers. However, the full impact of the current obesity epidemic on the cancer burden, including the long-term effect of obesity that begins as early as in childhood, is not well understood.

THE RECOMMENDED AMOUNT OF PHYSICAL ACTIVITY

Adults should get 150-300 minutes per week of moderate-intensity activity or 75-150 minutes per week of vigorous-intensity activity, or an equal combination. Getting to or exceeding the upper limit of 300 minutes is ideal.

When combining different types of activity, 1 minute of vigorous activity can take the place of 2 minutes of moderate activity. For example, 150 minutes of moderate activity, 75 minutes of vigorous activity, and a combination of 100 minutes of moderate activity plus 25 minutes of vigorous activity all count as the same amount.

This level of activity has been shown to have clear health benefits, including lowering the risk of dying at an early age and lowering the chance of getting or dying from certain types of cancer. Higher amounts of physical activity may be even better for lowering cancer risk.

For people who are not active or just starting a physical activity program, activity levels below the recommended levels can still help your health, especially your heart. The amount and intensity of activity can then be increased slowly over time. Most children and young adults can safely do moderate and/or vigorous activities without checking with their doctors. But men older than 40 years, women older than 50 years, and people with chronic illnesses or risk factors for heart disease should check with their doctors before starting a vigorous activity program.

Children and teens should be encouraged to be active at moderate to vigorous intensities for at least an hour a day, every day. This should include muscle-strengthening activities at least 3 days a week. Activities should be age appropriate, enjoyable, and varied, including sports and fitness activities in school, at home, and in the community. To help reach activity goals, daily physical education programs and activity breaks should be provided for children at school, and "screen time" (TV viewing, playing video games, or time spent on the phone or computer) should be limited at home.

Limiting time spent sitting
There is growing evidence that the amount of time spent sitting is important, regardless of your activity level. Sitting time raises the risks of obesity, type 2 diabetes, heart disease, and some types of cancer, as well as of dying at a younger age.

Lifestyle changes and advances in technology have led to people being less active and spending more time sitting each day. This is true both in the workplace and at home, due to increased TV, computer, and other screen time. Limiting the amount of time spent sitting, as suggested in the table below, may help maintain a healthy body weight and reduce the risk of certain cancers.

This is a condensed version of part of the article describing the American Cancer Society (ACS) Guideline for Diet and Physical Activity for Cancer Prevention. The full article (including references), which is written for health care professionals, is available online in CA: A Cancer Journal for Clinicians at: https://acsjournals.onlinelibrary.wiley.com/doi/full/10.3322/caac.21591