PM&R News   •   September 2019

In the age of smart watches and constant connectivity, we are often being told how active (or inactive) we are on a day to day basis. I know I feel a little more accomplished when my Apple watch seems to arbitrarily tell me that I’ve hit a certain threshold of steps taken or calories burned throughout the day. One commonly held belief with unclear origin is that 10,000 steps/day is a goal associated with good health. One prospective cohort study aimed to examine the associated of number of steps per day and stepping intensity with all-cause mortality, specifically in a group of older women. In a cohort of 16741 women with a mean age of 72 years, steps per day and step intensity were measured over 7 days, with follow up over the course of several years, and then mortality rates were compared between the groups of women stratified by steps per day. Other variables including sociodemographic variables, health habits and medical history were obtained in order to account for other potential confounding factors.

Participants were separated into quartiles based on how much they walked, and then the researchers tracked the mortality in each quartile over an average of 4.3 years of follow up. During the follow up, 504 women died. The researchers found that women who averaged approximately 4400 daily steps had lower mortality rates than those who took about 2700 steps per day. There were declines in mortality among women who took more steps, until about the level of 7500 steps/day, when death rates leveled out. Interestingly, walking faster or slower didn’t affect mortality rates.

There are of course limitations to a study like this, as we cannot just make a clear causative relationship between more steps per day and lower mortality rates. The researchers controlled for confounding variables as much as possible, and participants who had certain poor health risk factors were excluded. Still, this study is an interesting investigation into trying to put some reasoning behind reaching a certain number of steps per day, in a world in which we are increasingly connected to our devices that account for each step and calorie burned.

It would be interesting to do a similar study in different age and gender groups. While there is no need to tell patients to limit their amount of steps per day, and each patient has different considerations, perhaps for the older women cohort, this study suggests that 7500 steps/day is a good goal to aim for in patients who are looking for guidance in healthy practices.

Contributing Author: Eric Kessler, MD