It is crucial to monitor national and international trends regarding the aerobic fitness of children in order to understand better how these trends will affect future and current health. If you’re aerobically fit in adulthood, you are less likely than others to die or develop chronic diseases such as cardiovascular disease, stroke, and certain cancers. If you were active as a child, you’re more likely to remain fit and healthy in adulthood.
Think about your fitness level. When you were young, did you feel as fit as the kids of today?
In recent decades, this has been a hot topic. Many people believe that the fitness of children has decreased, others say it hasn’t changed at all, and few say it has improved.
Our research team spent the last two decades collecting fitness data from millions of children around the globe to help settle this debate.
Some kids are improving.
We systematically analyzed decades of data collected from hundreds of different studies in many countries to compare aerobic fitness between kids of the same age and gender.
In 2003, the research conducted was the first to show conclusively that aerobic fitness among kids declined around the globe at the end of the 20th century. In a very large study involving 25 million children aged 6-19 years in 27 countries, it was shown that aerobic fitness decreased worldwide between 1970-2000, with kids of 2000 being about 15 percent less active than their parents when they were young.
There are some encouraging signs that the fitness of children may not be declining. Recently, we published a new study in the British Journal of Sports Medicine that examined trends in aerobic fitness levels of one million kids aged nine to seventeen years in 19 high-income countries (such as Australia and Canada). We recently published to our 2003 study in the British Journal of Sports Medicine, which examined trends in the aerobic fitness levels of 1 million kids aged 9-17 years from 19 high-income countries (such as Australia, Canada, United States, etc.). We measured aerobic fitness by using the 20-meter shuttle test, also known as the “beep test” or the PACER Test.
The beep test is the most popular field test for aerobic fitness in children around the world. The beep test is a progressive fitness test that involves running continuously between two lines spaced 20 meters apart (66 feet) in time with recorded beeps. The distance between audio beeps is gradually reduced, and you are done when you cannot run 20 meters before the beep.
Our updated study confirmed the fact that aerobic fitness levels in children had declined during the 1980s and 90s. However, it is interesting to note that the decline has slowed down since 2000, with fitness levels plateauing in the last decade.
The international trends of aerobic fitness among 12-year-olds from 1980 to 2015. Grant Tomkinson provided CC-BY-SA
Fitness trends varied between countries, but most showed a general decline. After 2000, however, aerobic fitness improved in Brazil, Japan, Australia, Canada, and Greece. It plateaued in South Africa, Spain, Portugal, and the United States. Although today’s children are still less physically fit than when their parents were young, the gap has been reduced by about 7 percent.
What is the cause?
We looked at trends in aerobic fitness in relation to trends in socioeconomic and health factors, such as income inequality, physical activity, and overweight or obesity, in each country.
The Gini Index was the strongest indicator of a country’s level of fitness. The countries with the widest gap between rich and poor had the greatest declines in aerobic fitness from 2000 to 2014.
A growing number of people are poor in countries with an increasing gap between the rich and the poor. In high-income and upper-middle-income countries, poverty is associated with poor health and social outcomes. This phenomenon is known as social determinants. Indirectly, deprivation can lead to a lack of time, resources, and opportunities to engage in physical activity and participate in activities that increase or maintain aerobic fitness.
Assuming that this relationship is causal, policy changes that address income inequality and improve the social determinants for health in countries could result in improved aerobic fitness to stop the decline of fitness, as well as turn it around for all ages.
