Global sales of fitness trackers increased from $ 14 billion in 2017 to more $ 36 billion in 2020. The rapid success of these gadgets suggests that more people than ever see any value in keeping track of the number of steps they take, the stairs they climb, the time they spend sitting, and the calories they burn.
The manufacturers of these devices certainly want consumers to believe that tracking fitness or health-related behavior will encourage them to increase activity levels and make them healthier.
Our analysis of research published over the past 25 years suggests otherwise.
We are professors of kinesiology – the science of the movement of the human body – c Boyce Stateon University of Tennesseeand on University of North Florida. To find out if and how physical activity has changed over the years since fitness trackers became popular, we’ve analyzed more than two decades of research from several industrialized nations – all conducted before the COVID-19 pandemic.
Our systematic review of data from eight developed nations around the world shows that despite the jump in sales of fitness trackers, physical activity decreased from 1995 to 2017. Moreover, we found that this was not an isolated effect in one or two countries, but a widespread trend.
Review of the study
To conduct the study, we first looked for published studies that track physical activity such as walking, housework, or sports throughout the day. We wanted studies that received two “snapshots” of the daily activity of the population, with the measurements separated by at least one year.
We found 16 studies from eight different countries that met these criteria: Canada, the Czech Republic, Denmark, Greece, Japan, Norway, Sweden and the United States. The surveys were conducted between 1995 and 2017.
It is important to note that these snapshots do not track specific individuals. Rather, they followed samples from people of the same age group. For example, a Japanese study of physical activity among adults aged 20 to 90 collected data each year for 22 years from people in each age group.
Researchers track participants’ physical activity using a variety of carrying devices, from simple pedometers to more sophisticated activity monitors such as accelerometers.
The study groups ranged from large, nationally representative samples of tens of thousands to small samples of several hundred students from several local schools.
After identifying the research studies, we calculated the “effect size” for each study. The size of the effect is a method of adjusting the data to allow an “apple to apple” comparison. To calculate the magnitude of the effect, we used the data reported in the studies. These include the average physical activity at the beginning and end of each study, the sample size, and a measure of the variability in physical activity. Using a technique called meta-analysis, this allowed us to combine the results of all the studies to come up with a general trend.
We found that, in general, researchers have documented quite consistent declines in physical activity, with similar reductions in each geographic region for both sexes. In total, the reduction in physical activity per person is over 1100 steps per day between 1995 and 2017.
Our most striking finding was how sharply physical activity among adolescents aged 11 to 19 decreased – by about 30% – within a generation. For example, when we compared studies that measured physical activity in steps per day, we found that the total number of steps per day per decade decreased by an average of 608 steps per day for adults, 823 steps per day for children, and 1,497 steps per day for adolescents. .
Our study does not look at why physical activity has decreased over the past 25 years. However, the studies we reviewed mentioned some contributing factors.
More screen viewing, less walking or cycling
Among adolescents, the decline in physical activity is associated with increased ownership and use of smartphones, tablets, video games and social media.
At school, most of the physical activity that adolescents do traditionally comes from physical education classes. However, changes in the frequency of physical education classes during the school period are inconsistent and vary from country to country.
All of these factors may help explain the decline in physical activity we observed in our study.
In addition, fewer adults and children walk or cycle to school or work than 25 years ago. For example, in the late 1960s, most children in the United States were between the ages of 5 and 14 rode a bicycle or walked to school. Since then, this “active transport” has largely were replaced by car travel. Prices for travel by school bus or public transport have not changed much.
So why use a fitness tracker?
So, if levels of physical activity have fallen along with the growing popularity of fitness tracking, what makes these gadgets useful?
Fitness trackers can help raise people’s awareness of their daily physical activity. However, these devices are only part of the solution to tackling the problem of sedentary lifestyle. They are facilitators, not drivers of behavior change.
When a person’s physical activity decreases, it opens the door to generally reduced levels of fitness and other health problems such as obesity or diabetes. On the other hand, physical activity has a dramatic positive effect on health and well-being. The first step to increasing active movement is measuring it, which these devices can do. But successfully increasing overall physical activity requires several additional factors such as goal setting, self-monitoring, positive feedback, and social support.
Article from Scott A. CongerAssociate Professor of Exercise Physiology, Boise State University; David BassettProfessor and Head of the Department of Kinesiology, Recreation and Sports, University of Tennesseeand Lindsay Tothassistant professor of kinesiology, University of North Florida