Higher Daily Step Count Linked to Lower Mortality
A research team consisting of investigators from the National Institute of Aging (NIA), the National Cancer Institute (NCI) and the Centers for Disease Control and Prevention (CDC) just discovered that the number of steps a person takes per day is strongly associated with mortality, regardless of the intensity of stepping. Their findings were published in the Journal of the American Medical Association on March 24, 2020.
credit: Mussi Katz
To explain the purpose of the research, Pedro Saint-Maurice of NCI’s Division of Cancer and Epidemiology and Genetic, who is also the first author said, “While we knew physical activity is good for you, we didn’t know how many steps per day you need to take to lower your mortality risk or whether stepping at a higher intensity makes a difference. We wanted to investigate this question to provide new insights that could help people better understand the health implications of the step counts they get from fitness trackers and phone apps”.
Although earlier studies have investigated the relationship between step counts and mortality, their primary focus was on the elderly or people with debilitating health conditions. This study differed by tracking a representative sample of 4,800 40-year and above U.S. adults, who were gotten from CDC’s National Health and Nutrition Examination Survey. They wore accelerometers for about 7 days between 20003 and 2006. Thereafter, the National Death Index was used to follow their mortality through 2015. After controlling for variables like demographic, underlying health conditions, and other risk factors, the researchers established the link between step count/intensity and mortality.
The results were surprising. Using a reference of 4,000 steps per day, which is considered inadequate for adults, researchers found a 51% reduced risk for death from all causes in individuals that took 8,000 steps. As the number of steps increased to 12,000, mortality plunged by 65%.
NIA Intramural Research Program scientist and co-author, Eric Shiroma, Ph.D., highlighted how the study provides further evidence to support the theory that exercise in the form of moving helps to maintain health as we age.
The researchers further broke the participants into subgroups including; men and women; younger and older; white, black, and Mexican-American. And for all sub-classifications, the trend stayed the same. Moreover, secondary outcomes of the study showed that higher step counts reduced the risk of mortality from cancer and cardiovascular diseases.
After adjusting for step count, the researchers were startled no link existed between stepping intensity and mortality. However because only a few studies have been carried out to investigate the possible association, the authors recommend that more studies are needed before coming to a decisive conclusion. Janet Fulton, Ph.D., of CDC’s Division of Nutrition of Physical Activity and Obesity emphasized the effectiveness of physical activity in reducing the risk associated with heart disease, obesity, cancer, and type 2 diabetics. She then talked about the efforts by ‘Active People, Healthy Nation’ initiative to promote physical activity in local communities.
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