The Step Count “Sweet Spot”

The Step Count “Sweet Spot”

By Paige Mandel, MS RD CDN

 

 

A common knee-jerk response to the arbitrary question of “how many steps should I take in a day?” is most often 10,000 steps. But where did this magic number come from? I tried to ask myself this question as well, which led me to thinking… I don’t really know where that number in my head came from. While duration and intensity of exercise is an individualized recommendation, in almost all of my graduate nutrition courses and trainings we learned at least 150 minutes of moderate intensity exercise per week is optimal for the health of the general adult population. This actually comes from the Physical Activity Guidelines for Americans1, published by the U.S. Department of Health and Human Services. But, there was no evidence-based step count we were taught to recommend for such benefits.

 

The 10,000-steps target became popular in Japan in the 1960s, according to Dr. I-Min Lee, a professor of epidemiology at the Harvard T.H. Chan School of Public Health and an expert on step counts and health.2 This “magic step count” made way with the production of a pedometer, created to capitalize on consumer interest in fitness after the 1964 Tokyo Olympic Games. The pedometer’s name was written in Japanese characters which translated in English to “10,000 steps meter” and resembled the image of a walking man2. With this, came the popularity of the 10,000 step goal, which infiltrated the globe and fitness tracking industry. A target based on market capitalization, not necessarily science.

 

So now that we’ve surmised where the magic number came from we have to ask ourselves, is this legitimate? Will taking 10,000+ steps per day really have significant impact on my health and longevity? Until recent studies, the research highlighted the benefits of increased activity for increased longevity, with no marked point of reverse effect.

 

We know from previous research that people who are active are more likely to outlive those who are sedentary, as the risk of premature death decreases with increased movement. In 2018, the CDC concluded ~10% of all deaths among Americans 40-70 years of age are result of too little exercise3. In 2019, Dr. Lee and her colleagues found that the risk of early death for women in their 70’s was reduced by 40% for those women who completed 4,400 steps a day in comparison to those who completed 2,700 or less, with risks continuing to drop among women walking more than 5,000 steps2. This study saw a plateau of benefits around a step count of 7,500 daily steps2. In this study, there were only slight statistical benefits of additional steps up to and beyond the 10,000-step mark, demonstrating the gap in the research: is there an upper limit to the benefits of exercise for a longer, healthier life?  At this point, it was not completely clear whether we could overdo exercise, potentially contributing to a shorter life.

 

Two emerging studies were published this year, focusing on closing this gap and finding the exercise “sweet spot”, where the cost doesn’t outweigh the benefits.

 

One study published in August 2021 aimed to investigate the association between the duration of weekly leisure-time sports activity and all-cause mortality4(p). The results were observed as a U-shaped association, with lowest risk (highest benefit) for those participating in 2.6 to 4.5 weekly hours of activity. If you think about the shape of a U, the benefits lie at the bottom of the curve, a decrease in risk of mortality, where with both less AND more activity, benefits declined. Among the relatively few people who worked out for 10 hours or more per week, or about 90 minutes or so most days in this study, the results demonstrated a decline in benefit, increased risk of mortality by one third, comparative to people exercising for 2.6 to 4.5 hours a week3,4(p). This study concluded that the potential risks of very high activity levels should also be considered for inclusion in guidelines and recommendations4(p).

 

The second study published in September 2021, actually focused on the step count itself, further validating these results. The results demonstrated that participants accumulating at least 7,000 steps/day were 50% less like to have died since, than those who took fewer, with mortality risk decreasing up to 70% comparatively in those taking more than 9,000 steps/day3,5. Similarly to previous research, the benefits plateaued at 10,000 steps/day, with participants reaching this goal or more rarely outliving those who accumulated at least 7,0003,5.

 

With this new research, we can estimate the exercise “sweet spot” to be ~7,000-8,000 steps/day or 30-45 minutes of exercise most days. Not too little, not too much. It is most important to listen to your body to reap the meaningful benefits of exercise.

 

In summary, the most recent research tells us, yes, there is an association between increased activity and longevity/health benefits. The risk of premature death can be reduced by as much as 70% by incorporating the “right” amount of physical activity3. It also tells us no, being more active does not directly cause increased lifespan – we do not need to hit the “magic” 10,000 step count to reap the benefits of daily exercise for optimal health, sometimes less can be more.

 

References:

  1. Physical Activity Guidelines for Americans, 2nd edition. :118.
  2. Reynolds G. Do We Really Need to Take 10,000 Steps a Day for Our Health? The New York Times. https://www.nytimes.com/2021/07/06/well/move/10000-steps-health.html. Published July 6, 2021. Accessed October 27, 2021.
  3. Reynolds G. How Much Exercise Do We Need to Live Longer? The New York Times. https://www.nytimes.com/2021/09/15/well/move/exercise-daily-steps-recommended.html. Published September 15, 2021. Accessed November 15, 2021.
  4. Schnohr P, O’Keefe JH, Lavie CJ, et al. U-Shaped Association Between Duration of Sports Activities and Mortality: Copenhagen City Heart Study. Mayo Clin Proc. 2021;0(0). doi:10.1016/j.mayocp.2021.05.028
  5. Paluch AE, Gabriel KP, Fulton JE, et al. Steps per Day and All-Cause Mortality in Middle-aged Adults in the Coronary Artery Risk Development in Young Adults Study. JAMA Netw Open. 2021;4(9):e2124516. doi:10.1001/jamanetworkopen.2021.24516

 



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