If a woman gets breast cancer, having large breasts and living sedentary could increase their risk of dying from the disease.
Experts have that physical activity reduce the risk of getting breast cancer by approximately 25%.
However, the new study observed how both exercise and breast size could be used to predict the level of survival in the event of breast cancer, said study researcher Paul Williams, a scientist at the Lawrence National Laboratory. Berkeley, in Berkeley, California.
Williams found that the risk of dying from breast cancer was reduced by approximately 40% for women who were physically active, compared to those who did not comply with the exercise guidelines.
How size influences
To carry out the study, Williams and his team followed almost 80,000 women for 11 years. All were participants in national studies on the health of runners and walkers. Approximately 33,000 of the women were walkers and about 46,000 were runners.
By the time they entered the study, none of the women had been diagnosed with breast cancer. They all reported on the distances they walked or ran each week, in addition to the size of the bra and the body’s weight and height.
Those who met current exercise guidelines were about 42% less likely to die of breast cancer than those who did not.
These guidelines recommend two and a half hours of moderate activity, one hour and 15 minutes of intense activity or an equivalent combination during the week.
The amount of exercise they found that protected against breast cancer was: walk briskly about 7 miles (about 11.25 km) or run almost 5 miles (about 8 km) a week. Women with little time available may choose to run instead of walking, Williams said.
The study found that women with a cup of size C had a 4 times greater risk of dying from breast cancer than those who had a cup of size A. Those with a cup of size D, or greater, had a risk almost 5 times larger than those of size A.
Having higher levels of estrogen is a known risk factor for breast cancer, Williams said.
It has been shown that women with larger breasts have higher levels of estrogen than those with smaller breasts, if they have a narrow waist, but not if they have a wider waist, he said.
Women who are physically active are more likely to have a narrow waist than sedentary women.
Other healthy habits that could reduce cancer risk are to healthy body weight and limiting alcoholic beverages to one a day or less.
