Good physical fitness does not reduce obesity-related low-grade inflammation in children

Reviewed by Emily Henderson, B.Sc.Apr 3 2023

The increased prevalence of childhood obesity has resulted in an increased incidence of sustained low-grade inflammation starting from childhood. Obesity is the key factor in the increase of low-grade inflammation. However, high levels of physical fitness are thought to protect against obesity-induced health impairments. A study by the University of Jyväskylä (Finland) and the University of Eastern Finland found that good physical fitness itself does not reduce low-grade inflammation in children.

Sustained low-grade inflammation leads to insulin resistance and arterial dysfunction and promotes the development of heart diseases. A recent study examined how physical fitness affects the incidence of low-grade inflammation.

Children with better results in fitness tests, such as sit-ups, standing long jump, and agility shuttle run, also had a lower risk score for low-grade inflammation. Aerobic fitness, on the other hand, was not associated with low-grade inflammation.

However, higher body fat percentage, body mass index, and waist-to-height ratio had a much stronger connection to a higher low-grade inflammation than any physical fitness measure. The role of physical fitness as a determinant of low-grade inflammation also weakened once body fat percentage was considered in the analyses.

Physical fitness does not seem to have very much to do with a low-grade inflammation in childhood compared to, for example, body fat percentage or waist circumference."

Dr Eero Haapala, PhD, Faculty of Sport and Health Sciences, University of Jyväskylä

He continues: "Based on our study, physical fitness and, for example, the standing long jump can be a useful indirect method to identify children at elevated risk of low-grade inflammation."

Physical fitness testing in identifying risk groups may be helpful, especially when measuring body composition or waist circumference is too sensitive or if measuring them may be considered to encourage, for example, limiting eating and excessive weight monitoring.

The study examined the links between physical fitness indices and the risk score for low-grade inflammation in 391 primary-school children. The published research was based on the Physical Activity and Nutrition in Children Study conducted at the University of Eastern Finland.