Implications for practice and research

• Encouraging daily steps and increasing the daily time with high cadence steps may be important means to prevent morbidity and prolong lifespan.

• Assessment of daily steps over a longer period may further elucidate the shape of the dose–response relationship and better quantify the benefits of increasing daily step counts.

Context

Physical activity is widely recommended due to the extensive evidence supporting its numerous health benefits, including lower risks of morbidity and mortality. While current physical activity guidelines quantify their recommendations in terms of minutes of physical activity, step count has emerged as another popular metric for quantifying physical activity. However, studies examining whether step count impacts morbidity and mortality are sparser than studies of minutes of engagement in general physical activity. A recent study by del Pozo Cruz et al 1 addressed this gap by examining total step count, purposeful steps, incidental steps and stepping intensity in relation to mortality.

Findings

During a median of 7 years of follow-up, 10 245 individuals had incident cardivascular diease (CVD) events, 2813 had incident cancer events and 2179 died. More total daily steps, purposeful steps and incidental steps were associated with continually lower rates of all-cause mortality, CVD mortality and cancer until approximately 10 000 steps per day. Increasing step count beyond 10 000 steps per day did not appear to be associated with lower rates of CVD, cancer or death than 10 000 steps per day. Higher stepping intensity was also associated with continually lower rates of all-cause mortality, CVD mortality and cancer until approximately 80 steps per minute.

Commentary

These findings are a useful contribution to the literature on associations between step counts and mortality, and incidence of CVD and cancer, which may inform physical activity guidelines. The findings are broadly in line with a meta-analysis from 2022 that pooled 15 cohort studies with accelerometer-measured step count analysed in relation all-cause mortality.2

The study benefited from a large sample size, rich covariate availability and differentiating incidental steps from purposeful. Incidental steps may be more feasible to incorporate in everyday life, as they may represent the activity level associated with various activities of daily living. As such the findings regarding incidental steps may serve to increase awareness of simple and equitable approaches to engage in physical activity. A daily step count target may be an easily communicable health promotion message, and wearable devices offer a convenient method for tracking progress. Therefore, emphasising on step counts and other step metrics (ie, time spent stepping with high cadence) may be a viable approach to promote physical activity.

The evidence on step count and mortality and morbidity could be further strengthened by examination of changes in step count over time. In this regard, target trial emulation may serve as useful setup,3 which could bring further clarification to the exact target quantity that a study aims to estimate. Future studies with repeated assessment of daily steps over years of follow-up may also help to further elucidate the shape of the dose–response association. Such studies could enable the examination of accumulating step counts over the life course. As such, the important findings of del Pozo Cruz et al warrant further exploration of step counts and step cadence in relation to health outcomes.