The team of UCLA researchers analyzed data from a nationally representative cohort consisting of over 3,1000 adults who participated in the CDC’s National Health and Nutrition Examination Survey. Participants wore waist accelerometers to enable investigation of the dose-response association between the number of days with 8,000 steps or more with all cause and cardiovascular mortality over a 10-year follow-up period. The team notes that adjustments were made for numerous potential confounders such as race, ethnicity, marital status, smoking, sex, age, insurance status, comorbidities, and average daily step counts.
Findings showed that 62.5% of the cohort took at least 8,000 steps or more three to seven days per week. 17.2% reached the goal of 8,000 steps (approximately 4 miles) once or twice per week, and 20.4% were sedentary, participating in no exercise-level strolls at all.
Over the 10-year follow-up period, 14.2% of the participants died from all-cause mortality and cardiovascular mortality took another 5.3%. Compared to those who never walked 8,000 steps or more, all-cause mortality was found to be significantly lower among the moderate and heavy walking groups. The dose responses for cardiovascular and all-cause mortality were curvilinear, with the protective association from walking 8,000 steps or more plateauing at 3 days per week. Additionally, the associations remained close to constant among those who walked as much as 6-10,000 steps per day, which suggests that more steps may not be better for those with the main objective of longevity.
For those having a hard time participating in daily exercise, the authors suggest that “achieving recommended daily steps only a couple days per week can have meaningful health benefits.” “In line with the proliferation and popularity of smartphones and wearable devices that count daily steps, monitoring and targeting daily steps has been considered a practical strategy for promoting physical activity in the population by clinicians, patients and public health professionals.”
James Sawalla Guseh, MD, and Jose Figueroa, MD, MPH, both of Harvard, in a commentary state that Inoue, Ritz, and co-authors “provide valuable insight into the potential health benefits of low-frequency, step-based physical activity goals. This evidence supports the emerging and popular idea that step counting, which does not require consideration of exercise duration or intensity, can offer guidance toward robust and favorable health outcomes.”
However, they both emphasize that physical durability is just one measure of the desirable effects,” [I]t is important to note that these data merit replication and likely miss other important dimensions of health, such as neurologic health. Recent evidence indicated that higher thresholds (e.g., 9,800 steps per day) and higher intensities may be important for higher-order benefits, including reductions in incident dementia.”
