September 18, 2006

Editor's Note: This article has been updated to reflect changes made in the area of physical activity and cancer. The 2003 version was titled, Exercise and Cancer.

Physical activity is good for everyone. Physical activity can reduce the risk of certain cancers, improve quality of life, and is helpful for reducing stress in people living with cancer. However, despite the many proven benefits of physical activity, Americans are not incorporating enough physical activity into their daily routines. The Centers for Disease Control and Prevention (CDC) estimates that more than 50% of American adults do not get enough physical activity to prove beneficial to their health, and more than 25% are not active even in their leisure time. Unfortunately, statistics involving children and adolescents are not any more promising. More than one-third of high-school students do not participate in regular, high-intensity physical activity, and two-thirds of students are not enrolled in a physical education class. In short, parents need to be role models of a physically active lifestyle for the health of future generations as well as their own.

Physical activity reduces the risk of certain cancers

In 2003, an Institute of Medicine (IOM) report estimated that lifestyle changes (quitting smoking, making healthy food choices, and having a physically active lifestyle), as well as participation in regular cancer screening, could lead to the prevention of nearly 100,000 new cases of cancer and 60,000 cancer deaths each year.

Research shows that physical activity may be particularly helpful in reducing the risks of certain types of cancer, including breast and colon cancers. The National Cancer Institute (NCI) recommends exercising four or more hours a week to lower breast cancer risk. Physical activity has been shown to lower levels of estrogen, testosterone, insulin, and growth factors, which may accelerate the rate at which cancer cells are growing and dividing.

Other studies show that regular, consistent physical activity can reduce the risk of colon cancer by an average of 40% to 50%. One way that physical activity lowers the risk of colon cancer by accelerating the digestive process, which, in turn, reduces the amount of time the lining of the bowel is exposed to harmful substances. There is also encouraging research on the effects of physical activity on the risk of prostate, lung, and endometrial cancers.

Physical activity improves quality of life

Physical activity is not only helpful in the prevention of certain types of cancer, it has also been shown to significantly improve quality of life. Some benefits of physical activity are listed below.

• Improves overall fitness
  
  
• Helps to maintain a healthy body weight
  
  
• Reduces the percentage of fat in the body
  
  
• Reduces fatigue and improves endurance and stamina
  
  
• Improves immune system functioning
  
  
• Improves mood and self-esteem, lowers stress levels, and promotes healthy psychologic well-being
  
  
• Helps to relieve symptoms of depression and anxiety
  
  
• Improves quality of life of cancer survivors

Physical activity can also influence cancer recurrence (return) and survival. Studies have found that breast cancer and colon cancer survivors who walked three to five hours each week were able to lower their risk of death by 50%, compared with those who were sedentary. A 2006 study published in the Journal of Clinical Oncology (JCO), found that people with early and advanced bowel cancer who exercised routinely after treatment ended were more likely to survive. (Read the Editorial on this study.) According to other research published in 2003 in JCO, men with prostate cancer experienced improved quality of life and decreased levels of fatigue by participating in a moderate-resistance exercise regimen. Physical activity helps to regulate hormones associated with prostate cancer risk. (This is similar to breast cancer.). Discuss with your doctor and health-care team an exercise plan that is appropriate for your medical history and individual fitness goals.

Adding physical activity to your lifestyle

There are many ways you can creatively add physical activity to your lifestyle.

• Combine fitness activity with your daily household tasks, such as gardening, mowing the lawn, raking leaves, and walking the dog.
  
  
• Choose a parking spot that is further from your destination and take advantage of the opportunity to walk.
  
  
• Use the stairs instead of the elevator.
  
  
• Take brisk walks during a break at work. Walk to a coworker's office rather than sending an e-mail or picking up the phone.
  
  
• Involve your friends and family in recreational activities and plan outings that involve physical activity, such as tennis, hiking, and swimming.
  
  
• Jump rope, lift weights, or do cal esthetics during TV commercials.
  
  
• Ride your bike to work; this is good for the environment as well.
  
  
• Play with your children–basketball, dodgeball, hide and seek.
  
  
• Challenge a friend to a long-term activity goal such as hiking to the top of a local mountain, swimming a mile, running or walking a half marathon, etc.

To maintain a physically active lifestyle, adults should participate in moderate-intensity activity at least 30 minutes a day for five or more days a week. According to the American Cancer Society (ACS), exercising at a moderate to vigorous intensity level for 45 minutes or more five days a week has been shown to provide the greatest benefit in lowering the risk of breast and colon cancers.

Physical activity recommendations for children include at least one hour of moderate-intensity to vigorous-intensity exercise at least five or more days each week.

Important physical activity information for people living with cancer

• Before you begin an exercise program, be sure to talk with your doctor and health-care team. It's important to design a program that is specific to your fitness goals.
  
  
• The amount of physical activity that is recommended depends on your individual medical condition. It is important to not overexert yourself. Do the best you can and stay as consistent as possible with your physical activity routine.
  
  
• Start with a short physical activity routine. Gradually increase the time and intensity level of your routine. Some studies have shown that high-intensity physical activity may actually be counterproductive and may adversely affect the immune system. The rule for the general public is to increase your time spent exercising by no more than 10% each week.
  
  
• Be sure to choose activities you enjoy. These may include gardening, dancing, or walking. This will help to prevent boredom and will increase the likelihood that you will continue the activity. Some people like the same routine while others like to mix it up–either way you'll benefit.
  
  
• Involve water sports in your physical activity regimen. Swimming is an excellent form of physical activity, as it incorporates cardiovascular and weight-resistant physical activity. Also, swimming and water aerobics are much easier on your joints than other weight-bearing forms of physical activity.
  
  
• Some people find other forms of physical activity, such as Tai Chi or yoga, to be rewarding and stimulating to both mind and body. These forms of physical activity may also help to improve flexibility and promote relaxation.

Additional resources

American Cancer Society: Make Exercise Work for You

American Institute for Cancer Research: For Cancer Survivors, Exercise Tips

Centers for Disease Control and Prevention: The Importance of Physical Activity

Centers for Disease Control and Prevention: Why should I be active?

National Cancer Institute (NCI): Physical Activity and Cancer Fact Sheet

More Information

Prevention: Physical Activity and Cancer Risk

Prevention: Physical Activity Suggestions and Tips