James M. Pivarnick, Ph.D
Professor, Department of Physical Education
and Exercise Science
What kinds of cancer may be most affected by physical activity?
Although there have been some reports indicating that physical activity may be of benefit in preventing all types of cancers, so far scientists have found that physical activity provides the greatest protection against colon cancer and breast cancer.

 

How many people are likely to get these types of cancer?
The Centers for Disease Control and Prevention predicted that approximately 133,000 individuals would develop colo-rectal cancer in 1996, and almost 55,000 individuals would die from the disease in the U.S. They also estimated that almost 185,000 women would develop breast cancer, and over 44,000 would die from the disease in 1996. Clearly, these cancers have a serious impact on many of our citizens.

 

How can something like physical activity really affect my body to prevent cancer?
In colon cancer, scientists think it may be related either to a) the length of time the food remains in the gut before it is digested or excreted (this time decreases with exercise) or b) that certain chemicals and hormones produced during exercise may reduce the amount that cells in the colon tissue multiply. With breast cancer, it may be related to the female hormones (estrogen and progesterone) that are altered with activity.

 

What kind of physical activity program has been shown to be beneficial to one's health, possibly preventing chronic disease such as cancer?
Physical activity should be performed for several minutes (at least 10 minutes, build up to 30 minutes or more, if possible) at a time. Physical activity should be performed on most days of the week. That is, include physical activity in your day at least four out of every seven days.

Focus on moderate physical activities, such as a brisk walk, since moderate physical activity has greater health benefits than less demanding activities, such as a stroll in the park. There are many types of activity that "qualify" as moderate physical activity. Most people know how they feel when they take a "brisk" walk. Aim for this feeling when performing the physical activity you choose. That is, in order to increase the health benefits of physical activity, you should feel at least comparable to how you feel when you take a brisk walk. Some individuals who are already physically active on a regular basis may wish to perform more intense activities.

 

What are the best physical activities to do in order to help prevent cancer and other chronic diseases?
There is no one answer to this question. We can only say that the best "types" of activities are those where you use a lot of your muscles in some sort of rhythmic fashion for a sustained period of time. These are known as "aerobic" activities, because you use a lot of oxygen when you do them. Examples are walking, jogging, swimming, dancing, and active sustained yard work. The real answer is that the "best" activity is the one that you enjoy enough to do on a regular basis, hopefully for the rest of your life.

 

How long do I need to continuously perform my physical activities each day?
That is a good question, and one that we really don't know the answer to right now. Our recommendation is that a person should maintain his/her physical activity for at least 10 minutes at a time and eventually work up to 30 minutes at a time. The point is to accumulate at least 30 minutes of moderate physical activity in a given day.

 

Do I have to participate in organized sports or join a health club to receive any protection against the risk of cancer?
You don't always have to participate in organized sports and games to get your benefits from physical activity. Many activities of daily life "count" when it comes to reducing your chance for developing chronic diseases such as cancer. It is possible that your current job gives you enough physical activity to provide some protection against cancer. Maybe you are currently already doing some physical activity, and you simply need to add a few minutes, or days, to your present habits.

Examples of activities that have the greatest health effects:

MODERATE

  • Brisk walking
  • Dancing
  • Heavy house cleaning (mopping, window washing, sweeping garage) with effort
  • Mowing lawn (while walking)

VIGOROUS

  • Jogging
  • Cross country skiing
  • Climbing stairs or hills with a load
  • High impact aerobic dancing

MODERATE/VIGOROUS OCCUPATIONS

  • Construction work
  • Ditch digging or other shoveling
  • Using power tools
  • Farming (feeding cattle, shoveling grain)

 

If I've never been very active, how do I start?
First, answer the following questions:

Has your doctor or health care provider ever said you have a heart problem or other condition that would prevent you from starting a regular program of physical activity?

Do you ever get chest pains when you perform physical activity?

Do you ever get dizzy, lightheaded, or other feelings of uneasiness when you perform physical activity?

Has your doctor or health care provider ever recommended you take medication for high blood pressure, diabetes, or heart condition?

Do you have any other type of physical limitation that might prevent you beginning a regular physical activity program?

Can you think of any other reason either from your doctor's advice, or your own experience, that you should not begin a regular exercise program?

If you answered yes to any of the previous six questions, please see your doctor or health care provider before beginning a regular exercise program.

If there are no physical conditions that would limit physical activity, then set a realistic physical activity goal. For example, you might do one or more of the following:

  • Walk briskly for at least 10 minutes during your lunch break at least three times a week.
  • Turn on music and dance for at least 10 minutes most evenings.
  • Join your children in active play, such as jumping rope or playing basketball.

 

How do I know if I'm doing enough physical activity?
If you have begun a regular physical activity program, how often do you perform MODERATE and/or VIGOROUS exercise at this time?

MODERATE activities are those that make you feel the way you feel when you walk briskly.

VIGOROUS activities are those that make you feel the way you feel when you jog or run.

In the past six months, how often have you performed MODERATE activities?

  • Less than once a week
  • Between one and three times per week
  • More than three times per week
  • Daily

In the past six months, how often have you performed VIGOROUS activities?

  • Less than once a week
  • Between one and three times per week
  • More than three times per week
  • Daily

The recommended goal is to accumulate at least 30 minutes of moderate physical activity each day. How does the amount of physical activity you do compare to this goal?

If you are meeting the goal, great!

If you are not meeting the goal, you might try increasing your activity by:

  • Adding an additional day to your physical activity program
  • Increasing the length of time you do physical activity during the day
  • Working a little harder when you do physical activity.

 

Sometimes it's hard to stick with my physical activity program. Do you have any suggestions?
There are times when it is difficult to stick with a physical activity program. To stick with it, you might try:
  • Doing some of your activities with a friend or family. The support of family and friends could help you succeed.
  • Being involved in a variety of activities. Sometimes people get bored with a limited number of activities. Being active should be enjoyable. Remember that the best physical activity program is one that you enjoy enough to stick with it for the rest of your life.