Women who have not been very physically active over the years are 40% more likely to experience a fall when they reached their 70s, according to new research published in the British Journal of Sports Medicine.

The study involved over 11,700 participants (with an average age of 54) in the Australian Longitudinal Study on Women’s Health, which has been following the health of over 57,000 Australian women in four different age cohorts.

For this study, which lasted 18 years, women born from 1946 to 1951 reported every three years how much exercise they had been getting. That level of weekly physical activity participation was based on the total of three types of exercise: walking briskly and moderate and vigorous leisure activity. When participants were age 68 to 73, they were also asked about falls and related injuries they had experienced.

In addition to the higher risk of falls for women who generally didn’t get much exercise (less than 100 minutes per week), there was a 38% increased risk for women who had had high levels of physical activity around age 49 (on average about 400 minutes per week) but then decreasing levels from age 55 onward.

To protect against falls, exercise must be ongoing, the researchers concluded. And, they add, to promote that goal, older adults should aim for more than 150 minutes of exercise per week.

“All falls, even those that don’t result in injury, can leave older adults feeling scared of falling again,” one of the study’s authors, Wing Kwok, a researcher from the University of Sydney, said in an email, “making it difficult for them to live independently and potentially stopping them from doing the activities they enjoy.”

When people avoid activities and exercise, she said, it can cause their physical health to decline even further. And as the study found, this creates a vicious cycle in which falls and injuries can happen again.

According to the Centers for Disease Control and Prevention, falls were a leading cause of injury for U.S. adults age 65 and older and in 2021 caused more than 38,000 deaths.