Breast cancer survivors may be able to extend their lives, just by taking a brisk walk every day, a new study suggests.
The value of regular exercise -- including the oft-cited daily walk -- is well known. One of the potential health benefits is a lower risk of developing breast cancer.
But it has not been clear whether regular physical activity can help people who've already had breast cancer live longer. The new findings, published Nov. 17 in JAMA Network Open, suggest it can.
Researchers found that among more than 300 women who survived early-stage breast cancer, those who were moderately active were 60% less likely to die during the study period than those who were more sedentary.
In fact, those moderate exercisers had the same survival advantage as breast cancer survivors who exercised more vigorously.
That's "good news," said senior researcher Reina Haque, since it suggests that intense workouts are not necessary.
Moderate exercise has a host of health benefits, including helping control blood pressure, blood sugar and body weight, said Haque, a senior cancer epidemiologist with Kaiser Permanente Southern California in Pasadena.
And the new findings, she said, suggest that women can reap those benefits after breast cancer, too.
Breast cancer is highly treatable, especially when caught early. Among women diagnosed when the cancer is confined to the breast, 99% are still alive five years later, according to the American Cancer Society (ACS).
And while breast cancer survivors are -- like everyone else -- encouraged to maintain healthy habits such as regular exercise, there has been little evidence on whether exercise helps them live longer, said Erika Rees-Punia, a senior principal scientist with the ACS.
She said the new findings may encourage more survivors to become active, or keep up what they are already doing.
The study involved 315 women who had been diagnosed with early-stage breast cancer at least two years prior, and were, on average, 71 years old. At the outset, they reported on their recent physical activity habits.
Overall, 77 women were deemed moderately active, meaning they fit in activities like brisk walking or bicycling on most of the days of the week. Another 141 women were considered more vigorously active, as they favored activities like running, and 97 women fell into the "insufficiently" active category.
Over the next eight years, 14% of all study participants died, but the rate was substantially lower among active women: In both exercise groups, the death rate was roughly 1.3% per year, versus 3.3% per year in the more sedentary group.
Of course, there could be many other differences between breast cancer survivors who exercise regularly and those who do not. So Haque's team tried to account for those factors -- including age, the types of cancer treatments women had undergone, and whether they were bothered by fatigue or had other medical conditions or a history of depression.
And physical activity was still linked to a 60% reduction in the risk of dying during the study period.
"They did a good job of accounting for other things that we'd expect could explain this association," Rees-Punia said.
There's no debate over the health benefits of physical activity, and both researchers said they believe the findings reflect a real effect of an active lifestyle.
"Physical activity is great for almost everyone out there," Rees-Punia said. "And this is another piece of evidence on why it's important to be active after a breast cancer diagnosis."
The study focused on deaths from any cause, not breast cancer specifically. Haque noted that when women survive early-stage breast cancer, they more often die of other causes than from a cancer recurrence. Of the 45 study participants who died, five died of breast cancer.
Rees-Punia said the study leaves one question open: If a woman had been sedentary before her cancer diagnosis, can she extend her life by taking up exercise now?
Regardless, given the potential health benefits, Rees-Punia said she hopes the new findings encourage more breast cancer survivors to make physical activity part of their lives.
The American Cancer Society has advice for breast cancer survivors.
SOURCES: Reina Haque, PhD, MPH, senior cancer epidemiologist, Kaiser Permanente Southern California Department of Research and Evaluation, Pasadena; Erika Rees-Punia, PhD, MPH, senior principal scientist, behavioral and epidemiology research, American Cancer Society, Atlanta; JAMA Network Open, Nov. 17, 2022, online