Exercise May Cut Ovarian Cancer Risk
Benefit Reported With Moderate but Not Vigorous Physical Activity
May 16, 2005 -- Moderate exercise may reduce the risk of ovarian cancer, the
leading cause of gynecological cancer death.
The news comes from a Canadian study in The International Journal of
Cancer's online edition. Women weren't asked to work out. Instead, they
completed surveys about their activities.
Moderate physical activity was associated with a lower risk of ovarian
cancer. Vigorous exercise didn't raise or lower ovarian cancer risk, the study
Ovarian cancer has few symptoms and is often diagnosed late. It has a poor
prognosis because of the advanced stage of the disease at the time of
diagnosis. While there are a few risk factors which increase its risk,
identifying modifiable risk factors could reduce the risk of developing ovarian
Benefits of Being Active
Exercise has already been shown to guard against colon and breast cancers,
say the researchers, who included Sai Yi Pan of Canada's Public Health Agency.
Previous research on ovarian cancer had mixed results, they say.
Pan's study analyzed data from 442 women with ovarian cancer and 2,135 women
of similar backgrounds who did not have ovarian cancer. They were 20-76 years
Questionnaires asked how many times per month they walked, jogged, ran,
gardened, swam, skied, skated, bowled, took exercise classes, or did other
activities. Age, number of children, diet, and use of alcohol and cigarettes
were also noted.
Lower Risk Seen With Moderate Activity
Women who participated in the highest levels of moderate-intensity exercise
had a decreased risk of ovarian cancer compared with women with lower levels of
moderate intensity activity. Moderate levels of physical activity were defined
as being equivalent to walking three to six times per week or golfing one or
two times per week.
Decreased ovarian cancer risk was seen in women with high levels of moderate
recreational physical activity before and after menopause, the study shows.
Overweight and obese women benefited a bit more than leaner women. Obesity,
especially around the waistline, has been shown to increase ovarian cancer
risk, and physical activity can reduce that fat. However, physical activity
also lowered ovarian cancer risk for women with normal BMI, say the
researchers, so other factors must come into play.
Women in Ontario also rated their activity at work. Ovarian cancer risk was
also found to be lower in women with moderately active jobs.
Women with the highest levels of vigorous physical activity were not found
to significantly reduce their risk of ovarian cancer.
How does physical activity help? No one is certain, but Pan outlines several
Exercise might help the body's antioxidant and immune system defenses,
combat obesity (especially around the waist), or affect hormones. Severe
exercise could push the body too far, say researchers.
Reams of research have shown that activity rewards virtually the entire
body, including the heart, bones, waistline, and brain.