Senior women may be able to reduce their risk of developing heart disease by increasing the number of hours they spend in low intensity activities, such as walking and gardening, a new study suggests.
In the study of nearly 6,000 older women, researchers found women in the highest category of daily low intensity activity were 42 per cent less likely to experience a heart attack or die from heart disease compared to those in the lowest category. And every extra hour of light activity per day appeared to cut women's risk even further, according to study results published in JAMA Network Open.
Current physical activity guidelines suggest 150 minutes a week of moderate and vigorous physical activity, said the study's lead author, Andrea LaCroix, director of the Women's Health Center of Excellence at the University of California, San Diego. "That's been a non-starter for many older women like the ones in the study whose average age was 79," LaCroix said. "The bottom line in this study is that everything we do, even lower intensity physical activities, looks beneficial to the heart."
The current guidelines, LaCroix said, "were developed by people who were not studying older women. Yet older women disproportionately experience heart disease".
For the new study, LaCroix and her colleagues recruited 5,861 women, ages 63 to 99, to wear a device called an accelerometer for one week. The device kept track of when the women sat or reclined and when they got up and moved around. It was also able to report on the intensity of the women's activities.
On average, women in the most active group spent more than 5.6 hours per day in light activity, while the least active group spent less than 3.9 hours a day doing something other than sitting or lying down.
During nearly four years of follow-up, there were 143 new heart attacks and deaths from heart disease and 570 new cases of cardiovascular disease (including not just heart attacks and deaths but also heart failure, stroke, procedures to reopen clogged arteries, and other heart and blood vessel problems).
After accounting for factors such as age, race or ethnicity, BMI, blood pressure, cholesterol levels, smoking status and alcohol consumption, the researchers found that women who spent the most hours in light activity were 42 per cent less likely to have heart attack or die from heart disease compared to those who spent the least hours active, and they were 22 per cent less likely to develop new cardiovascular disease.
The study wasn't a controlled experiment and so it can't prove that light activity directly reduces women's cardiovascular risk. One of the study's strong points, however, is that women's activity levels were measured by the devices, LaCroix said. Because women don't keep track of the time they spend engaged in everyday activities such as doing the laundry, when they fill out a questionnaire they tend to underestimate how much they are moving around.
The new study is "very important", because shows that women can lower their risk of heart disease simply by spending less time sitting, said Dr Elsa Giardina, director of the Center for Women's Health at the NewYork-Presbyterian/Columbia University Irving Medical Center and a professor of medicine at the Columbia University Irving Medical Center.
"It addresses a population that is really underrepresented in a lot of studies and happens to be one of the fastest growing populations in the US," Giardina said. "This is also a population that often doesn't get the drugs (to treat heart disease) or recommended for physical therapy so they tend to have worse outcomes."
"The takeaway message is that low intensity physical activity can be a really pleasant and inexpensive way to reduce cardiovascular disease risk in older people," Giardina said.