Sales of fitness trackers increased from US$14 billion to over $36 billion in a single year. The success of these gadgets suggests that more people are interested in keeping track of calories burned, steps taken, flights of stairs climbed, and time spent sitting.

The manufacturers of these devices want consumers to believe that tracking fitness or health-related behaviors will make them healthier.

Over the past 25 years, our analysis of research suggests otherwise.

The University of North Florida, the University of Tennessee, and the University of Idaho are where we teach the science of human body movement. We analyzed more than two decades of research from several industrialized nations to find out if and how physical activity has changed since fitness trackers became popular.

Despite the surge in sales of fitness trackers, physical activity declined from 1995 to 2017, according to a systematic review of data from eight developed nations around the world.

This was not an isolated effect in one or two countries, but a widespread trend.

Reviewing the research

We searched for published research that tracked physical activity such as walking, household activities, or playing sports throughout the day to conduct the study. We were looking for studies that obtained two Snapshots of daily activity from a population and separated them by a year.

Canada, the Czech Republic, Greece, Japan, Norway, Sweden, and the United States are some of the countries that we found studies from. The studies were done over two decades.

snapshots did not track specific individuals They tracked samples from the same age group. One Japanese study of physical activity among adults ages 20 to 90 collected data every year for 22 years from people in each age group.

Scientists tracked the physical activity of the participants using a variety of devices, from simple pedometers to more sophisticated activity monitors.

The study groups ranged from large, nationally representative samples numbering tens of thousands of people to small samples of several hundred students from a few local schools.

We calculated the effect size for each study after identifying the research studies. The effect size is a method of adjusting the data to allow for an apples-to-apples comparison. The data reported in the studies were used to calculate the effect size.

The sample size, average physical activity at the beginning and end of the study, and a measure of variability in physical activity are included. We used a technique called meta-analysis to combine the results of all the studies and come up with a trend.

Researchers documented declines in physical activity with the same decreases in each geographical region and in both sexes.

The decrease in physical activity per person was over 1,100 steps per day.

In the span of a single generation, the amount of physical activity decreased for adolescents ages 11 to 19 years.

The total steps per day declined by an average of 608 steps per day in adults, 823 steps per day in children, and 1,497 steps per day in adolescents when we compared the studies.

Our study does not address why physical activity has declined over the past 25 years. Some contributing factors were mentioned in the studies we reviewed.

More staring at screens, less walking or bicycling

There was a correlation between decreases in physical activity and increases in ownership and use of mobile devices.

In the U.S., screen time increased in adolescents from five hours per day in 1999 to 8.8 hours per day in 2017).

Most of the physical activity that adolescents perform comes from physical education classes. The changes in the number of physical education classes vary from country to country.

The decline in physical activity that we observed in our study may be explained by all of these factors.

Fewer adults and children are walking to school or work than 25 years ago.

In the late 1960s, most children in the U.S. rode a bicycle or walked to school. Active transportation has largely been replaced by automobile trips. The rates of travel by public transportation have not changed.

So why use a fitness tracker?

If levels of physical activity have dropped at the same time that fitness tracking has grown, what makes these gadgets useful?

People can increase their awareness of their daily physical activity with fitness trackers. The problem of sedentary lifestyles is only addressed by these devices. They are not the drivers of behavior change.

When a person's physical activity goes down, it opens the door to other health problems such as obesity or diabetes.

Physical activity has a positive impact on health and well-being.

The first step in increasing active movement is to measure it. Increasing physical activity requires more than just goal setting and positive feedback.

Scott A. Conger is an Associate Professor of Exercise Physiology at Boise State University, David Bassett is a Professor and Department Head of Recreation and Sport Studies at the University of Tennessee, and Lindsay Toth is an assistant professor at the University of North Florida.

This article is free to use under a Creative Commons license. The original article is worth a read.