Reference
Del Pozo Cruz B, Ahmadi MN, Lee IM, Stamatakis E. Prospective associations of daily step counts and intensity with cancer and cardiovascular disease incidence and mortality and all-cause mortality. JAMA Intern Med. 2022;182(11):1139-1148.
Study Objective
To investigate associations between steps (total steps and type of steps) and mortality (all-cause, cancer, and cardiovascular disease [CVD]) and incidence (cancer and CVD)
Key Takeaway
People taking up to 10,000 steps per day reduce risk of death (from cancer, CVD, or any cause) and risk of cancer and CVD incidence, with periods of higher cadence providing additional benefit
Design
Observational, prospective cohort study
Participants
This large study included 78,500 participants. Mean age was 61 years, and the vast majority (97%) were White. Females comprised 55% of the sample.
Investigators drew participants from the larger UK Biobank study (2013–2015). They mailed accelerometers to those who accepted the invitation to participate and asked them to wear an Axivity AX3 accelerometer for 24 hours per day for 7 days.
Inclusion criteria:
- Participants with valid data were included. This is defined as:
- A minimum of 3 “valid monitoring days,” meaning 16 hours of wear time or more per day. Days do not need to be consecutive;
- Inclusion of 1 weekend day;
- Inclusion of sleep periods (no duration specified).
Exclusion criteria:
Participants were excluded if:
- They self-reported poor health;
- They had active cancer or cardiovascular disease;
- Data were missing for any covariates (age, smoking status, education, and others).
In general, the participants in this study were healthier and of higher socioeconomic status than patients in the larger UK Biobank study.
Study Parameters Assessed
This study went beyond simply counting steps; it also assessed the types of steps that participants were taking (incidental vs purposeful) and their intensity, evaluating whether different health outcomes are associated with each type of step.
Primary exposures were:
- Daily step counts (median number of steps over valid monitoring days)
- Types of steps:
- Incidental steps (defined as fewer than 40 steps per minute)
- Purposeful steps (more than 40 steps/minute)
- Step cadence:
- Peak 30-min cadence (defined as the 30 nonconsecutive minutes each day with the highest step count)
Investigators drew participant health data from national databases in England, Wales, and Scotland (through October 2021) to identify:
- Deaths from and diagnoses of cancer (bladder, breast, colon, endometrial, esophageal, gastric, head and neck, kidney, liver, lung, myeloid leukemia, myeloma, and rectal)
- Hospitalizations for all causes
- Deaths from all other causes
Primary and secondary diagnoses were included. Named cancer sites are those most associated with low levels of physical activity.1
Primary Outcome
Association of incident cancer and cardiovascular disease, as well as all-cause mortality, relative to step count and step intensity in the study population
Key Findings
Median follow-up was 7.0 years (53,196 person-years), and in this time, there were 2,179 deaths, including 1,324 from cancer and 664 from CVD. CVD occurred in 10,245 people, and cancer in 2,813.
All outcomes listed below were statistically significant.
Daily step counts:
For every incremental increase of 2,000 steps, the risk of all-cause mortality had a relative decrease of 8%, cancer mortality 11%, and CVD mortality 10%.
Note: Personal communication with the corresponding author confirmed several typographical errors. All values in the Results section should be preceded with a minus (“–”) sign.
Incidental steps (<40 steps/minute):
For every incremental increase of 10%, risk of all-cause, cancer, and CVD mortality was lowered by 6%, 6%, and 10%, respectively.
Purposeful steps (≥40 steps/minute):
For every incremental increase of 10%, risk of all-cause, cancer, and CVD mortality was lowered by 7%, 8%, and 10%, respectively.
Peak 30-min cadence (the 30 daily minutes with highest step counts):
For every incremental increase of 10%, risk of all-cause, cancer, and CVD mortality was lowered by 8%, 9%, and 14%, respectively.
Incidences of cancer and CVD were reduced by similar amounts, ranging from 4% to 7%.
Transparency
This work was supported by an investigator grant from the National Health and Medical Research Council and by the University of Southern Denmark.
Practice Implications & Limitations
The concept of walking 10,000 steps per day to achieve better health is thought to have been popularized by a Japanese pedometer manufacturer in the 1960s.2 The study by Del Pozo Cruz et al, being reviewed here, set out to explore whether this convenient figure really is the best target for everyone.
With 78,500 people included in the study, the authors fail to find a minimum threshold for the number of steps linked to reduced risk of mortality and morbidity from cancer, CVD, and other causes. In other words, moving even a little bit reduces the risk of dying or getting cancer or CVD.
Step counts have been evaluated in other studies that appear to echo the idea that 10,000 might not be the right target for everyone. Lee et al looked at a slightly older cohort (mean age of 72 years vs 61 years in this study) and found mortality reductions that plateaued at about 7,500 steps.3 Paluch et al found that drops in all-cause mortality rates were maximized at 6,000 to 8,000 steps in people aged 60 years, and at 8,000 to 10,000 steps in those under 60 years.4 Higher step counts still seem to be more helpful than lower ones, but perhaps that 10,000-step target isn’t the whole story.
The intensity of the steps we take also seems to matter.
Before you start scaling back your patient recommendations, note that the Del Pozo Cruz study identified multiple dose-response relationships. Every 2,000 steps taken by participants was associated with a reduction in the risk of dying of cancer by 11% and of CVD by 10%. This lowering of deaths for every 2,000 steps held true until that magic figure of about 10,000 steps.
The intensity of the steps we take also seems to matter. Higher intensity, or “purposeful,” steps that we take on a walk (≥40 steps/minute) are associated with a lower risk of all outcomes studied, slightly more than for those steps taken wandering into a room and wondering why you are there (“incidental” steps at <40 steps/minute). People who clocked a faster pace on average over their speediest 30 minutes each day also saw greater risk reductions in incidence of CVD and cancer, or of dying from these or other causes.
Once again, investigators observed dose-response relationships. For every 10% increase in incidental or purposeful steps, risk of mortality outcomes was 6% to 10% lower. An incremental increase of 10% in peak 30-min cadence was associated with an 8% to 14% lower mortality rate.
Is it possible to take too many steps? Figures included in this paper suggest a U-shaped curve, appearing to associate the highest number of steps (>20,000/day) and highest peak 30-min cadence (>100 steps/min) with less stellar reductions in cardiovascular outcomes, although the differences are not statistically significant. Do we need to start telling our patients to stop walking at 10,000 steps? Probably not.
Providing a perspective to the contrary, a 2017 study of mail carriers in Glasgow found that higher step counts (>15,000/day) were associated with fewer metabolic risk factors for CVD, although mortality was not evaluated.5 This does seem to be more in line with what we would expect from higher levels of activity.
Additionally, the authors of the paper under review here cite “statistical uncertainty” over the threshold of 10,000 steps, which may be the result of simply having fewer participants in the 10,000-plus step club. Future research may clarify whether there is any harm in walking more than 10,000 steps per day. This paper does not identify a statistically significant danger.
This study provides some important information that we can communicate to our patients. First, any amount of movement that you can do is beneficial. This brings to mind my elderly or palliative patients who are still getting around their own homes, walking up the stairs, and doing light housework. These patients may feel that a target of 10,000 steps is daunting and off-putting. It is nice to be able to offer evidence that their efforts to keep moving are clearly beneficial.
Second, it seems that more really is better. The fact that the evidence is less certain beyond 10,000 steps may be something of a self-fulfilling prophesy. The popularity of the 10,000-step target may result in fewer people exceeding this target, leaving us with less evidence to support higher step counts at this time. In any case, this paper supports the suggestion to do as much movement as you can, at least up to 10,000 steps.
Finally, higher-intensity exercise may be more beneficial. Your mortality and morbidity risks will likely be reduced more by going for a brisk walk outside than by ambling from the couch to the fridge between Netflix episodes, even if your step count is similar.
Step counters are a convenient way for patients to measure their activity and may actually prompt people to move more.6 In a 2018 Canadian survey, over a quarter of participants had a wearable fitness tracker.7 These popular devices allow patients and clinicians to set and evaluate movement goals together. Having data to inform our choice of exercise targets will make fitness trackers a more appropriate tool for everyone.
