based on prospective data from more than 2,000 people.
Findings were consistent regardless of race or sex, and step intensity had no impact on mortality risk, reported lead author Amanda E. Paluch, PhD, of the University of Massachusetts Amherst, and colleagues.
“In response to the need for empirical data on the associations of step volume and intensity with mortality in younger and diverse populations, we conducted a prospective study in middle-aged Black and White adults followed up for mortality for approximately 11 years,” the investigators wrote in JAMA Network Open. “The objectives of our study were to examine the associations of step volume and intensity with mortality overall and by race and sex.”
Steps per day is easy to communicate
Dr. Paluch noted that steps per day is a “very appealing metric to quantify activity,” for both researchers and laypeople.
“Steps per day is simple and easy to communicate in public health and clinical settings,” Dr. Paluch said in an interview. “Additionally, the dramatic growth of wearable devices measuring steps makes it appealing and broadens the reach of promoting physical activity to many individuals. Walking is an activity that most of the general population can pursue. It can also be accumulated throughout daily living and may seem more achievable to fit into busy lives than a structured exercise session.”
The present investigation was conducted as part of the Coronary Artery Risk Development in Young Adults (CARDIA) Study. The dataset included 2,110 participants ranging from 38-50 years of age, with a mean age of 45.2 years. A slightly higher proportion of the subjects were women (57.1%) and White (57.9%).
All participants wore an ActiGraph 7164 accelerometer for 1 week and were then followed for death of any cause, with a mean follow-up of 10.8 years. Multivariable-adjusted Cox proportional hazards models included a range of covariates, such as smoking history, body weight, alcohol intake, blood pressure, total cholesterol, and others. Step counts were grouped into low (less than 7,000 steps per day), moderate (7,000-9,999), and high (at least 10,000 steps per day) categories.
Compared with individuals who took less than 7,000 steps per day, those who took 7,000-9,000 steps per day had a 72% reduced risk of mortality (hazard ratio, 0.28; 95% confidence interval, 0.15-0.54). Going beyond 10,000 steps appeared to add no benefit, based on a 55% lower risk of all-cause mortality in the highly active group, compared with those taking less than 7,000 steps per day (HR, 0.45; 95% CI, 0.25-0.81).
Walking faster didn’t appear to help either, as stepping intensity was not associated with mortality risk; however, Dr. Paluch urged a cautious interpretation of this finding, calling it “inconclusive,” and suggesting that more research is needed.
“It is also important to note that this study only looked at premature all-cause mortality, and therefore the results may be different for other health outcomes, such as the risk of cardiovascular disease, or diabetes, cancer, or mental health outcomes,” Dr. Paluch said.
“The results from our study demonstrated that those who are least active have the most to gain,” Dr. Paluch said. “Even small incremental increases in steps per day are associated with a lower mortality risk during middle age. A walking plan that gradually works up toward 7,000-10,000 steps per day in middle-aged adults may have health benefits and lower the risk of premature mortality.”