Highlights
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Introduction
Physical activity is associated with a reduced risk of all-cause mortality and improved quality of life. In contrast, a sedentary lifestyle (typically defined as <5000 steps/day) is significantly associated with an increased risk of all-cause, cardiovascular (CV) and oncological disease mortality, and an increased risk of type 2 diabetes. Due to its high prevalence, a sedentary lifestyle is called the disease of the 21st century .
Epidemiological data show that insufficient levels of physical activity affect 27.5% of people worldwide, with this percentage being much higher among women than men (23.4 vs. 31.7%) and among people from high-income countries compared to low-income countries (36.8 vs. 16.2%). In recent years, it has been shown that the global prevalence of low physical activity has decreased. Furthermore, if current trends continue, the 2025 global physical activity target (a 10% relative reduction in insufficient physical activity) will not be met.
It should be noted that 81% of adolescents worldwide perform insufficient physical activity. Between 2001 and 2016, a slight reduction was found in the incidence of low physical activity among boys (77.6 vs. 80.1%), but not among girls (84.7 vs. 85.1%). According to data collected by the World Health Organization, insufficient physical activity is the fourth most common cause of death in the world (~1.5 billion people worldwide are physically inactive and 3.2 million deaths per year are related with physical inactivity).
The COVID-19 pandemic has also resulted in reduced levels of physical activity. Before the outbreak of the COVID-19 pandemic in 2019, the global average daily steps were 5323.8 The number of steps during the pandemic decreased significantly and, more importantly, had not returned to baseline after 2 years. Consequently, everything possible should be done to improve the overall level of physical activity. Even a minimal change (from inactivity to low physical activity) can bring clinically significant benefits, such as a reduction in the risk of death. The simplest form of physical activity is walking .
Currently, the recommended number of steps for most people by the Centers for Disease Control and Prevention (CDC) is 10,000 steps per day . As already mentioned, the average daily number of steps before the COVID-19 pandemic was 5,323 (US: 4,774; UK: 5,444; China: 6,189), which is substantially lower than the CDC recommendation . It is worth emphasizing that what really matters is the number of daily steps taken, not necessarily the intensity of the exercise. In a study of 4,840 Americans, a higher number of daily steps was found to be significantly associated with lower all-cause mortality ; however, no significant association was observed between step intensity and mortality after adjusting for the total number of steps/day.
Despite these emerging public health benefits of walking, current European guidelines for physical activity have not yet published specific recommendations on the optimal number of steps per day necessary for good health and longevity. Any approach to increasing the level of physical activity of the population through the promotion of safe, accessible and environmentally friendly activities is insufficient without a recommendation for a defined level of physical activity.
The wide availability of step counters (smart watches, mobile phones and pedometers) means that they are increasingly used to self-monitor physical activity. In addition, the use of pedometers can help increase the number of steps taken per day. In a meta-analysis of 70 randomized clinical trials, step count control was shown to lead to increases in short- and long-term step counts.
Based on the above, the objective of this meta-analysis was to evaluate the dose-response relationship between step count and all-cause mortality and CV.
Goals
There is good evidence showing that inactivity and walking minimal steps per day increase the risk of cardiovascular (CV) disease and poor general health. However, the optimal number of steps and their role in health is still unclear. Therefore, in this meta-analysis, we aimed to evaluate the relationship between step count and all-cause mortality and CV mortality.
Methods and results
Relevant electronic databases were systematically searched from baseline to June 12, 2022. Primary endpoints were all-cause mortality and cardiovascular mortality. An inverse variance weighted random effects model was used to calculate the number of steps/day and mortality. Seventeen cohort studies with a total of 226,889 participants (generally healthy or patients at CV risk) with a median follow-up of 7.1 years were included in the meta-analysis .
An increase of 1000 steps was associated with a 15% decrease in the risk of all-cause mortality [hazard ratio (HR) 0.85; 95% confidence interval (CI) 0.81–0.91; P < 0.001], while an increase of 500 steps was associated with a 7% decrease in CV mortality (HR 0.93; 95% CI 0.91–0.95; P < 0.001).
Compared to the reference quartile with median steps/day 3967 (2500–6675), quartile 1 (Q1, median steps: 5537), quartile 2 (Q2, median steps 7370), and quartile 3 (Q3, median steps 11,529) were associated with a lower risk of all-cause mortality (48, 55, and 67%, respectively; P < 0.05, for all).
Similarly, compared to the lowest quartile of steps/day used as reference [median steps 2,337, interquartile range 1,596–4,000], the highest quartiles of steps/day (Q1 = 3,982, Q2 = 6,661, and Q3 = 10,413) were linearly associated with a reduced risk of CV mortality (16, 49, and 77%; P < 0.05, for all).
Using a restricted cubic splines model, we observed a nonlinear dose-response association between step count and all-cause mortality and CV (nonlinearly P < 0.001, for both) with progressively lower mortality risk with increasing step count.
Conclusions
In this meta-analysis of 17 studies, a statistically significant inverse association was observed between daily step count and all-cause mortality and CV mortality.
Our results can be used to promote public awareness about the importance of physical activity, particularly walking, which is easily implementable.
Final message There is strong evidence showing that sedentary living can significantly increase the risk of cardiovascular (CV) disease and shorten lifespan. However, the optimal number of steps, both the cut-off points at which we can see health benefits and the upper limit (if any), and their role in health are still unclear. In this meta-analysis of 17 studies with almost 227,000 participants that evaluated the health effects of physical activity expressed by walking as measured by the number of steps, we showed that an increase of 1,000 steps was correlated with a significant reduction in mortality for all causes of 15%, and similarly, an increase of 500 steps was correlated with a reduced risk of CV mortality of 7%. Furthermore, using the dose-response model, we observed a strong inverse nonlinear association between step count and all-cause mortality with significant differences between the younger and older groups. It is the first analysis that not only analyzed age and sex, but also regional differences based on climatic zones and, for the first time, evaluates the effect of up to 20,000 steps/day on the results (confirming the more, the better ) , which was lost in the previous analyses. The analysis also revealed that depending on the results, we do not need that many steps to have health benefits from even 2500/4000 steps/day, which, in fact, undermines the hitherto definition of a sedentary life. |
