In older women, higher daily walking volume measured by accelerometer is inversely associated with all-cause mortality, with the greatest reduction in mortality risk observed at approximately 4,400 steps per day compared to 2,700 steps per day.

Study: The association between daily step count and all-cause and cardiovascular mortality: a meta-analysis.

The study found that walking more steps each day is linked to a lower risk of dying from any cause, especially when going from about 2,700 to over 4,000 steps a day, which supports the claim.

Study: Association of Step Volume and Intensity With All-Cause Mortality in Older Women.

The study found that older women who walked about 4,400 steps a day had much lower chances of dying during the study than those who walked about 2,700 steps, which matches the claim.

Study: Accelerometer-measured physical activity, sedentary behavior, and mortality among cancer survivors: the Women’s Health Accelerometry Collaboration

The study shows that older women who walk more steps each day have a lower risk of dying from any cause, and the biggest benefits happen up to about 5,000–6,000 steps a day. This generally supports the idea that walking more helps, even if the exact number in the claim is a bit lower.