For many women in their 70s, 80s, and beyond, the big questions are simple: Does walking still matter? Is it “too late” to protect memory? A recent study in the Women’s Health Initiative followed women with an average age of 82 and used accelerometers—small devices worn on the body—to measure daily steps, sitting time, and minutes of moderate-to-vigorous physical activity (MVPA). The researchers then tracked who developed mild cognitive impairment (MCI) or probable dementia.

The results were encouraging: women who moved more—especially those who took more steps and spent more time in at least moderate-intensity activity—had a lower risk of developing MCI or probable dementia over about four years of follow-up.

What the study did

This research used data from the Women’s Health Initiative, a long-running study of older women in the United States. A group of 1,277 women, with a mean age of 82 years (± 6 years), wore accelerometers that recorded:

• Steps per day
• Minutes per day of moderate-to-vigorous physical activity (MVPA)
• Time spent sitting

After the accelerometer measurements, the women were followed for a median of 4.2 years. During this time, 267 women developed incident MCI or probable dementia. These diagnoses were not based on a single test or self-report; they were rigorously adjudicated using clinical information.

The researchers used statistical models (Cox regression) that adjusted for age and other health factors to estimate how different levels of steps and MVPA were related to the risk of developing MCI or probable dementia.

What they found about movement and memory

The study grouped women into four levels (quartiles) of daily MVPA and daily steps. Compared with the lowest group, women in higher groups generally had a lower risk of MCI or probable dementia.

• Moderate-to-vigorous physical activity (MVPA):
  Across MVPA quartiles, the adjusted hazard ratios (HRs) for MCI/probable dementia were approximately 1.00 (reference), 1.28, 0.79, and 0.69, with a significant trend (P-trend = 0.01). A higher MVPA level was associated with lower risk.
• Steps per day:
  Across step-count quartiles, the adjusted HRs were about 1.00 (reference), 0.73, 0.64, and 0.38, with a strong trend (P-trend < 0.001). Women in the highest step group had roughly a 62% lower risk compared with the lowest group.
• Each meaningful increase in activity:
  For each 1-standard-deviation increase in MVPA (about 31 minutes per day), the HR was 0.79. For each 1-standard-deviation increase in steps (about 1,865 steps per day), the HR was 0.67.
• Sitting time:
  Sitting, by itself, was not clearly associated with MCI/probable dementia in this study.

In plain language: among women in their 80s, those who took more steps and spent more time in at least moderate-intensity activity had a lower chance of developing MCI or probable dementia over the next several years.

Comparison: Steps, MVPA, and sitting

One of the most interesting findings is that steps and MVPA mattered more than total sitting time. For older women in their 80s, adding movement—especially walking and other moderate-intensity activities—seemed more important than simply trying to reduce sitting.

What this means for older adults

For women (and men) in their 70s, 80s, and beyond, this study offers a hopeful message: it may not be too late for movement to matter. Even in their 80s, women who walked more and moved at a moderate intensity had a lower risk of developing MCI or probable dementia over the next few years.

This does not prove that walking or MVPA directly prevent dementia. It is an observational study, so it shows associations, not cause and effect. Women who move more may also have other healthy habits or fewer medical problems. Still, the use of accelerometers and adjudicated diagnoses makes the findings strong and relevant when thinking about everyday choices.

Practical ways to use this information

If you are an older adult, especially in your late 70s or 80s, here are some ways to apply these findings in a realistic, gentle way:

• Track your steps: If you use a pedometer, phone, or watch, note your usual daily steps. Consider gradually adding 500–1,000 steps per day, working toward an extra 1,800–2,000 steps if it feels safe.
• Include moderate-intensity movement: This might be a slightly brisk walk, walking with a friend, or climbing a few extra stairs—enough to feel your breathing pick up a bit, but still able to talk.
• Build movement into your day: Short walks after meals, walking indoors at a store or hallway, or gentle outdoor loops can all add up.
• Respect your limits: If you have heart disease, lung disease, balance problems, or joint pain, talk with a clinician before making big changes. Small, steady increases are usually safer than sudden jumps.

The key message is not perfection, but more movement than you are doing now, in a way that fits your health, safety, and comfort.

Important cautions

This study cannot prove that physical activity or steps directly prevent MCI or dementia. The follow-up period was relatively short (about 4.2 years), and the women were already in their 80s, so results may not apply to all ages or to men. Also, accelerometers capture movement but not every detail of how that movement feels or why someone is more or less active.

If you have medical conditions, are at risk for falls, or take medications that affect blood pressure or heart rhythm, discuss any plan to increase activity with a clinician who knows your history. Movement can be powerful, but it should be tailored to your situation.

Reference

The study abstract is available here:
Nguyen S, LaCroix AZ, Hayden KM, Di C, Palta P, Stefanick ML, et al.
Accelerometer-measured physical activity and sitting with incident mild cognitive impairment or probable dementia among older women.
Published January 25, 2023, in Alzheimer’s & Dementia.
DOI: 10.1002/alz.12908