Proceed with caution
The current study findings should be interpreted cautiously in light of the potential unmeasured confounding factors and selection bias that often occur in studies of physical activity, James Sawalla Guseh, MD, of Massachusetts General Hospital, and Jose F. Figueroa, MD, of Harvard T.H. Chan School of Public Health, Boston, wrote in an accompanying editorial.
The results support previous studies showing some longevity benefits with “weekend warrior” patterns of intense physical activity for only a couple of days; however, “the body of evidence for sporadic activity is not as robust as the evidence for sustained and regular aerobic activity,” the authors emphasized.
The editorial authors also highlighted the limitations of the current study, including the observational design and significant differences in demographics and comorbidities between the 1- to 2-days of 8,000 steps exercise group and the 0-day group, as well as the reliance on only a week’s worth of data to infer 10 years’ mortality.
Although the data are consistent with previous observations that increased exercise volume reduces mortality, more research is needed, as the current study findings may not reflect other dimensions of health, including neurological health, they said.
Despite the need for cautious interpretation of the results, the current study “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,” and may inform step-based activity goals to improve public health, the editorialists wrote.
The study was supported by the Japan Agency for Medical Research and Development, the Japan Society for the Promotion of Science, the Japan Endocrine Society, and the Meiji Yasuda Life Foundation of Health and Welfare. Dr. Inoue also was supported by the Program for the Development of Next-Generation Leading Scientists With Global Insight sponsored by the Ministry of Education, Culture, Sports, Science and Technology, Japan. The other researchers had no relevant financial conflicts to disclose. The editorial authors had no financial conflicts to disclose.