Physical activity can reduce morbidity and mortality due to multiple chronic conditions, including cardiovascular disease, type 2 diabetes, and several cancers, and is associated with better quality of life.
World Health Organization 2020 guidelines on physical activity and sedentary behaviour.
The number of steps acquired per day is a simple measure of physical activity. Monitoring daily steps is more feasible than ever for the general public as fitness trackers and mobile devices have become increasingly popular.
Fortune Business Insights The global fitness tracker market is projected to grow from $36.34 billion in 2020 to $114.36 billion in 2028 at a CAGR of 15.4% in forecast period 2021–2028.
Although the goal of 10 000 steps per day is widely promoted as being optimal for general health, it is not based on evidence, but instead originates from a marketing campaign in Japan.
Association of step volume and intensity with all-cause mortality in older women.
Expert committees from the WHO 2020 Physical Activity Guidelines and US 2018 Physical Activity Guidelines identified a gap in research on the dose–response association between volume and intensity of physical activity and health outcomes, including physical activity measured by step volume and rate.
World Health Organization 2020 guidelines on physical activity and sedentary behaviour.
The optimal number of steps needed to reduce the risk of mortality might be affected by characteristics such as age or sex. Walking volume and pace decrease with age and might differ by sex; hence, the distribution of steps differs in younger and older adults and by sex.
Association of daily step count and step intensity with mortality among US adults.
Several observational studies have shown stepping rate, a marker of intensity, is inversely associated with mortality; however, when adjusted for volume of steps per day, step rate was no longer associated with mortality.
Steps per day and all-cause mortality in middle-aged adults in the Coronary Artery Risk Development in Young Adults study.
A meta-analysis observed a linear association between step volume and mortality from seven studies, observing large heterogeneity among studies and did not report associations by age, sex, or stepping rate.
Daily step count and all-cause mortality: a dose-response meta-analysis of prospective cohort studies.
Research in context
Evidence before this study
No evidence-based public health guidelines exist that recommend a specific number of steps per day for health benefits. We previously published a systematic review of the literature of daily steps and associations with all-cause mortality, cardiovascular disease, and dysglycaemia. Findings from prospective studies show mortality risk plateaus for older women (aged ≥62 years) at 7500 steps per day and among nationally representative samples of US and Norwegian adults at approximately 8000–12 000 steps per day. Observational studies have shown that stepping rate, a marker of intensity, is inversely associated with mortality; however, when adjusted for volume of steps per day, stepping rate is no longer significantly associated with mortality. A meta-analysis that used the effect estimates directly reported by seven publications found a linear association between step volume and mortality, observing large heterogeneity among studies and did not report associations by age, sex, or stepping rate. The Steps for Health Collaborative is an international consortium formed to determine the prospective association between device-measured step volume and rate with health outcomes, including mortality.
Added value of this study
This meta-analysis of 15 prospective cohort studies from Asia, Australia, Europe, and North America (including 47 471 adults and 3013 deaths) provides evidence-based thresholds for the optimum number of steps per day associated with reduced risk of all-cause mortality. Each cohort study completed a standardised statistical analysis created by The Steps for Health Collaborative and these results were then meta-analysed. Compared with adults in the lowest steps per day quartile, adults in the highest steps per day quartile had a 40% to 53% lower risk of mortality. Taking more steps per day was associated with a progressively lower risk of all-cause mortality, up to a level that was similar by sex but varied by age. There was progressively lower risk of mortality among adults aged 60 years and older until about 6000–8000 steps per day and among adults younger than 60 years until about 8000–10 000 steps per day. We found inconsistent evidence that step intensity was associated with risk of mortality beyond total volume of steps.
Implications of all the available evidence
Number of daily steps is a simple and feasible measure for monitoring and promoting physical activity globally as fitness trackers and mobile devices increase in popularity. Our findings suggest mortality benefits, particularly for older adults, can occur at levels less than the popular reference value of 10 000 steps per day. The findings from this meta-analysis can be used to inform step guidelines for public health promotion of physical activity.
Here, we aimed to complete a meta-analysis on steps per day and mortality, addressing the limitations of previous studies. We aimed to include a larger sample of studies than previous meta-analyses and to collect data across age groups and by sex to generate robust evidence to inform a daily step count guideline. Our primary objective was to assess the dose–response association between steps per day and all-cause mortality and determine whether this association varied by age and sex. A secondary objective was to assess the association between stepping rate and all-cause mortality. We hypothesised that a dose–response association exists between steps per day and mortality and that the association would differ between younger and older adults.
Results
We identified 15 studies that were eligible for inclusion in our meta-analysis (figure 1), including four studies in Europe, one in Japan, one in Australia, eight in the USA, and one that included data from 40 countries (table; appendix pp 3–4). Seven studies were published
Dose-response associations between accelerometry measured physical activity and sedentary time and all cause mortality: systematic review and harmonised meta-analysis.
Objectively assessed physical activity and lower limb function and prospective associations with mortality and newly diagnosed disease in UK older adults: an OPAL four-year follow-up study.
Objectively measured physical activity, sedentary behaviour and all-cause mortality in older men: does volume of activity matter more than pattern of accumulation?.
The American Cancer Society’s Cancer Prevention Study 3 (CPS-3): recruitment, study design, and baseline characteristics.
with study start dates ranging between 1999 and 2018.
TableSelected characteristics of included studies
Data are n or n (%), unless otherwise stated. Mean data are presented with SD in parentheses. LFE=low-frequency extension. NA=not applicable.
The total sample included 47 471 participants (individual-level mean age 65·0 years [SD 12·4], 32 226 [68%] were female, and >70% were of White race [appendix pp 6–8]), with a median study follow-up time of 7·1 years (range 2·7–13·5 [IQR 4·3–9·9]; total sum of follow-up across studies was 297 837 person-years). The overall median of the median steps per day was 6495 [IQR 4273–8768]. Adults younger than 60 years had significantly higher median steps per day (7803 [IQR 5377–10 352]) than did adults aged 60 years and older (5649 [IQR 3686–8092]; p=0·033). A total of 3013 deaths were reported (10·1 per 1000 participant-years). The Newcastle Ottawa quality scores were high, ranging from 7 to 9 out of a possible 9 points (appendix p 10).
Compared with the lowest quartile of steps per day, higher quartiles of steps per day were associated with a reduced risk of mortality in the overall sample (figure 2; appendix p 13). Funnel plots had minor asymmetry for the second and third quartile comparisons among lower weighted studies with visual inspection (appendix p 14). Egger’s test for symmetry suggested no evidence of study selection bias (appendix p 14). There was a non-linear, dose–response association between steps per day and all-cause mortality in the spline model (pnon-linearityappendix p 15).
Figure 2Association between steps per day and all-cause mortality, in all participants, and by age and sex
Model 1 adjusted for age and sex (if applicable). Model 2 was further adjusted for device wear time, race and ethnicity (if applicable), education or income, body-mass index, plus study-specific variables for lifestyle, chronic conditions or risk factors, and general health status. The x-axis of the plot is on the log scale.
HRs for risk of mortality by age group (figure 2 and the appendix (pp 16–17). There was a significant interaction (p=0·012) by age group in the spline model (figure 3). The number of daily steps at which the HR for mortality plateaus among adults aged 60 years and older was approximately 6000–8000 steps per day and among adults younger than 60 years was approximately 8000–10 000 steps per day (figure 3).
Figure 3Dose-response association between steps per day and all-cause mortality, by age group
Thick lines indicate hazard ratio estimates, with shaded areas showing 95% CIs. Reference set at the median of the medians in the lowest quartile group (age ≥60 years = 3000 steps per day and interaction=0·012 by age group. 14 studies included in spline analysis, excluded Baltimore Longitudinal Study of Aging.
A roadmap to build a phenotypic metric of ageing: insights from the Baltimore Longitudinal Study of Aging.
The y-axis is on a log scale.
The HRs for mortality were similar for females and males (figure 2; appendix pp 20–21). The interaction by sex in the spline model was not significant (p=0·11). For males and females, the lowest HR for mortality was seen at approximately 7000–9000 steps per day (appendix p 23).
Seven studies reported stepping rate measures (table). Median peak 30-min stepping rate was 64·1 steps per min (IQR 52·9–80·5) and 60-min stepping rate was 57·5 steps per min (46·2–70·9). Median time spent walking at a rate of 40 steps per min or faster was 51·4 min (23·3–87·4) and at 100 steps per min or faster was 5·2 min (1·3–15·2). Higher stepping rates were associated with lower risk of mortality without adjustment for total steps (model 2; figure 4). The association between peak 30-min and peak 60-min rate measures and mortality remained significant after adjusting for steps per day (appendix pp 24–25). After adjusting for step volume, time spent walking at 40 steps per min or faster and at 100 steps per min or faster were not associated with mortality, except for the first versus second quartiles at a rate of 100 steps per min or faster (figure 4; appendix pp 26–27).
Figure 4Association between stepping rate with all-cause mortality, with and without adjustment for total step volume
Hazard ratios and 95% CIs are adjusted for age, device wear time, race and ethnicity (if applicable), sex (if applicable), education or income, body-mass index, and study-specific variables for lifestyle, chronic conditions or risk factors, and general health status. The model with additional adjustment for step volume uses the residual method for the rate variable. The x-axis is on a log scale.
Sensitivity analyses excluding deaths within the first 2 years of follow-up showed the association between steps per day quartiles and mortality was attenuated but remained significant (appendix pp 28–29). The association between step counts and mortality was stronger in the six studies with fewer than 6 years of follow-up (HR 0·32 [95% CI 0·25–0·41]) than among the nine studies with 6 years of follow-up or more (0·57 [0·49–0·66]) when comparing the lowest and highest quartile (appendix p 30). There was a significantly lower HR for published (0·54 [0·42–0·68]) than unpublished studies (0·73 [0·63–0·85]) when comparing the first and second quartile (appendix p 31). We found no appreciable differences in the association between steps per day and mortality when excluding any one study or step-counting device (appendix p 33). When reanalysing the data using a fixed-effects inverse-variance method, we found no change in the results (appendix p 12). In main analyses, heterogeneity (I2) was low to moderate, ranging from 0 to 57% across quartiles (figure 2).
Discussion
In this meta-analysis of 15 studies, seven published and eight unpublished, we found that taking more steps per day was associated with progressively lower mortality risk, with the risk plateauing for older adults (aged ≥60 years) at approximately 6000–8000 steps per day and for younger adults (aged <60 years) at approximately 8000–10 000 steps per day. We found inconsistent evidence that step intensity had an association with mortality beyond total volume of steps.
Our findings add to the body of research on steps and health by describing a curvilinear association and range in steps per day associated with all-cause mortality. The curvilinear association and 50–60% lower risk in the higher steps per day quartiles than in the lowest steps per day quartile is similar to the association and risks observed for time spent doing moderate-to-vigorous intensity physical activity and mortality,
Dose-response associations between accelerometry measured physical activity and sedentary time and all cause mortality: systematic review and harmonised meta-analysis.
and study-level publications on steps and mortality.
Step by step: association of device-measured daily steps with all-cause mortality-a prospective cohort study.
The steep early slope of the dose–response curve suggests increasing steps might be beneficial in terms of reducing risk of mortality, particularly among individuals who have lower step volumes. We observed a plateau in risk reduction, which varied by age group. We did not find that high step volumes were associated with increased risk of mortality.
Accelerometer-measured physical activity and sedentary time in a cohort of US adults followed for up to 13 years: the influence of removing early follow-up on associations with mortality.
suggesting that more recent physical activity might be more important for associations with mortality.
Contrary to the curvilinear dose response observed in our analysis, a recent steps and mortality meta-analysis of seven studies found a linear association for 2700–17 500 steps per day; however, this study was limited by sparse data being available at the upper end of the steps distribution, with only three effect estimates provided above 12 500 steps per day.
Daily step count and all-cause mortality: a dose-response meta-analysis of prospective cohort studies.
Because of the small number of studies included, this meta-analysis was unable to provide robust subgroup analyses and, therefore, was unable to examine associations by age or sex. Here, we included 15 studies and applied a standardised, meta-analytical method for data synthesis across studies, strengthening the reliability of our findings.
We found that thresholds of steps per day were different for younger and older adults because the steps per day versus mortality spline curves varied by age group. The curvilinear shape of the step count to mortality association was similar for older and younger adults, but the step volume associated with a given HR differed by age. In a study of older women (aged ≥62 years) by Lee and colleagues,
Association of step volume and intensity with all-cause mortality in older women.
We observed a similar plateauing at 6000–8000 steps per day for older individuals, and included both sexes and a slightly wider age group to enable us to identify ranges of steps per day for younger and older age groups, and by sex. As age increases, mobility limitations, decreases in aerobic capacity, and biomechanical inefficiencies might restrict the possible number of steps per day older adults can accumulate.
Limitations in activities of daily living in community-dwelling people aged 75 and over: a systematic literature review of risk and protective factors.
The association between daily steps and all-cause mortality might start at lower step volumes for older adults because of lower absolute step volume for the same relative step intensity and physiological stimulus than for younger adults. Therefore, older adults might require a lower number of steps to gain similar improvements in health benefits.
Association of daily step count and step intensity with mortality among US adults.
Increasing daily peak stepping rate in any (not necessarily consecutive) 30 min or 60 min period, independent of steps per day, was associated with reduced mortality.
How fast is fast enough? Walking cadence (steps/min) as a practical estimate of intensity in adults: a narrative review.
Conversely, adjusting for step volume, time spent walking at 40 steps per min or faster and 100 steps per min or faster were not associated with mortality. Peak stepping rate might better reflect fitness levels than thresholds of time spent walking at 40 or 100 steps per min or faster, and fitness is a strong predictor of mortality,
Physical fitness and all-cause mortality. A prospective study of healthy men and women.
which might partially explain why peak stepping rate might be more strongly related to mortality than the 40 and 100 steps per min thresholds. The time threshold measures we used here were developed in laboratory settings
Walking cadence (steps/min) and intensity in 41 to 60-year-old adults: the CADENCE-adults study.
and might not represent real-world patterns of walking. Peak stepping rate variables were more normally distributed than thresholds measures, allowing for easier detection of differences.
How fast is fast enough? Walking cadence (steps/min) as a practical estimate of intensity in adults: a narrative review.
For example, most participants spent little time walking at 100 steps per min or faster (median 5·2 min per day [IQR 1·3–15·2]). Time spent walking at a speed slower than 100 steps per min might be considered for future observational studies of the association between walking with health outcomes. Disentangling the health associations of stepping rates from step volume in daily life is difficult because individuals who walk at a faster pace usually accumulate more steps per day than those who walk at a slower pace. Trials prescribing different stepping rate groups while maintaining the same total step volume might be needed to fully examine the association between stepping rate and intermediate health outcomes (eg, hypertension or diabetes).
Taken together, our findings were inconclusive when determining if step intensity has additional mortality benefits beyond that associated with total steps.
The implications of our findings extend to health care and public health. Steps per day is a simple and easy to interpret measure that can enhance clinician–patient and public health communication for monitoring and promoting physical activity. Wearable devices that monitor steps, such as smartphones and fitness trackers, have substantially increased in popularity over the past decade and this popularity is expected to continue to increase.
Fortune Business Insights The global fitness tracker market is projected to grow from $36.34 billion in 2020 to $114.36 billion in 2028 at a CAGR of 15.4% in forecast period 2021–2028.
Many consumers rely on the number of steps provided from these devices to monitor their physical activity.
Our study has several limitations. The data are derived from observational studies; therefore, causal inferences cannot be made. We focused on all-cause mortality; however, the associations between steps and other health outcomes are important considerations when developing guidelines or providing clinical advice. Although we attempted to control for sociodemographic, lifestyle, and health status factors in our analyses, residual confounding and reverse causality might still be present. Steps were measured at a single timepoint. 1 week of device-measured steps has relative stability over several years,
Reproducibility of accelerometer-assessed physical activity and sedentary time.
but does not account for changes in steps per day over time. In this meta-analysis we used study-level data, and although we standardised our analyses across studies, heterogeneity in participants between studies (eg, demographics, health status) and design (eg, step-counting device, covariates) might not be fully accounted for compared with in individual-level pooled meta-analyses. We selected prespecified knots in splines, which risks model misspecification. All included studies were in high-income countries and participants were volunteers primarily among White populations, restricting generalisability of the findings. Future research should emphasise monitoring and promoting steps in populations at higher risk of mortality (eg, some race and ethnicity groups, low socioeconomic status, and individuals with or without high risk for chronic diseases). Since the development of this meta-analysis collaboration, to our knowledge, two studies on steps and mortality
Daily steps and diet, but not sleep, are related to mortality in older Australians.
have been published. The findings of these two studies, which included primarily older adults, are consistent with our results, with a greater number of daily steps being significantly associated with a decreased risk of all-cause mortality.
Device type, wear location, and walking speed and duration can affect the accuracy of step estimates. Step counts obtained from research and consumer devices are highly correlated but can vary by 20% or more;
Video-recorded validation of wearable step counters under free-living conditions.
therefore, estimates of steps per day reported here might not precisely match all devices. Stepping rate was measured as the number of steps accumulated per min rather than the number of steps while in motion and, therefore, might not adequately capture short walking periods, which are common in daily life.
Therefore, devices might underestimate steps particularly among frail older adults. Most of the participating studies used devices worn at the hip, whereas many consumer devices are worn on the wrist and can provide different estimates.
Video-recorded validation of wearable step counters under free-living conditions.
This meta-analysis has several strengths. The participant population was geographically diverse, and so the associations were generated with greater precision and relevance to a diverse population of individuals worldwide than would be possible in individual, country-level studies. Use of measures recorded by devices such as step counters and accelerometers might more accurately reflect the strength of the association between movement and mortality than self-reported activity.
A comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review.
Each study used a consistent methodological approach to minimise heterogeneity. Unpublished studies were invited to participate, which would have reduced publication bias. Positive findings tend to be published earlier and more often than negative findings;
The effect of publication bias magnitude and direction on the certainty in evidence.
therefore, if we had only relied on published evidence the estimated pooled effect size might have been overestimated. We found associations between daily steps and all-cause mortality in both published and unpublished studies, providing robust evidence for this association.
There are currently no evidence-based public health guidelines recommending the number of steps per day for health benefits. Our findings suggest mortality benefits, particularly for older adults, can be seen at levels less than the popular reference of 10 000 steps per day. Adults taking more steps per day have a progressively lower risk of all-cause mortality, up to a level that varies by age. Our findings can be used to inform step guidelines for clinical and population promotion of physical activity.
AEP, DRB, MRC, UE, KRE, DAG, BJJ, WEK, I-ML, CEM, JDO, AVP, CFP, ER-P, and JEF conceived and designed the study and interpreted the data. AEP, CFP, and SB did the statistical analyses and accessed and verified the underlying study data. AEP and JEF drafted the manuscript. All authors acquired the data. All authors critically revised the manuscript for intellectual content. All authors had full access to the data in the study and had final responsibility for the decision to submit for publication.
