Light physical activity from childhood is more effective than MVPA in reducing inflammation caused by being sedentary

Increased sedentary time from childhood through young adulthood worsened low-grade inflammation in a new follow-up study. However, the results also showed that light physical activity (LPA) may completely reverse the adverse process. Moderate-to-vigorous physical activity (MVPA) did not have a similar effect. The study was conducted in collaboration between the University of Bristol in the UK, the University of Exeter in the UK, and the University of Eastern Finland, and the results were published in the Journal of Clinical Endocrinology & Metabolism.

Newswise — Numerous diseases across the lifespan, including cardiovascular, metabolic, neurological, musculoskeletal conditions, and cancer, have been linked to the presence of low-grade inflammation. Additionally, recent findings indicate that low-grade inflammation might play a role in causing premature vascular damage among adolescents and young adults.

According to the World Health Organization, over 80% of adolescents worldwide do not engage in sufficient physical activity on a daily basis. This alarming statistic is projected to result in approximately 500 million cases of heart disease, obesity, diabetes, and other noncommunicable diseases by 2030. The economic impact of these health conditions is estimated to reach an annual cost of US$27 billion.

This alarming forecast regarding the morbid danger of physical inactivity necessitates urgent research on the most effective preventive approach.

The relationship between movement behavior, specifically measured through accelerometers, and low-grade inflammation in the pediatric population has not been previously examined over the long term. This is primarily because of the expenses involved and the difficulties associated with repeatedly measuring movement behavior within the same cohort as they transition from childhood to young adulthood. Conducting such studies for a duration of more than 10 years poses significant challenges and limitations.

The study utilized data from the University of Bristol's research project known as Children of the 90s, also referred to as the Avon Longitudinal Study of Parents and Children. The study involved a group of 792 children who were 11 years old at the start and were followed up until they reached the age of 24, resulting in a total follow-up period of approximately 13 years. Throughout this period, measurements of sedentary time, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) were collected using accelerometers at ages 11, 15, and 24.

In addition, levels of high sensitivity C-reactive protein, a marker of inflammation, were repeatedly measured at ages 15, 17, and 24. The children also underwent dual-energy X-ray absorptiometry scans to determine their total body fat mass and skeletal muscle mass. Furthermore, fasting blood samples were collected at ages 15, 17, and 24 to assess various factors such as glucose, insulin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride levels, smoking status, socio-economic status, and family history of cardiovascular disease.

Over the course of the 13-year follow-up period, the study found that sedentary time among the participants increased from around 6 hours per day during childhood to 9 hours per day in young adulthood. In contrast, light physical activity (LPA) decreased from 8 hours per day to 3 hours per day, while moderate-to-vigorous physical activity (MVPA) remained relatively stable, averaging around 50 minutes per day from childhood to young adulthood.

The study also discovered a significant association between increased sedentary time and heightened inflammation levels, which was partially mediated by elevated blood pressure. Specifically, it was observed that increased blood pressure accounted for only 8% of the relationship between sedentary time and inflammation. This indicates that while blood pressure plays a role in the link between sedentary behavior and inflammation, it is not the sole factor responsible for this connection.

From childhood to young adulthood, engaging in light physical activity (LPA) was found to be linked with decreased inflammation. Nevertheless, the impact of LPA was diminished by approximately 30% as body fat mass increased. Similarly, participating in moderate-to-vigorous physical activity (MVPA) during childhood was associated with reduced inflammation, but this effect was counteracted by an 80% reduction when total fat mass increased. Ultimately, the presence of significant fat mass effectively nullified the inflammation-reducing effect of MVPA.

Andrew Agbaje, a physician and clinical epidemiologist at the University of Eastern Finland, expressed his surprising findings regarding the impact of physical activity on inflammation. According to Agbaje, their research revealed that engaging in light physical activity (LPA) from childhood onwards may have a more positive effect compared to moderate-to-vigorous physical activity (MVPA) in counteracting the detrimental consequences of sedentary behavior on inflammation. Furthermore, Agbaje noted that even in healthy-weight children, the natural increase in total fat mass significantly weakened the inflammation-lowering effects of MVPA. This discovery sheds new light on the potential benefits of LPA in mitigating inflammation and highlights the unexpected influence of fat mass on the effectiveness of MVPA.

In a recent study, we have made an additional discovery that further underscores the importance of light physical activity (LPA) in promoting heart health among adolescents, surpassing the benefits of moderate-to-vigorous physical activity (MVPA). Our findings provide significant evidence that LPA might play a vital, yet often overlooked, role in disease prevention from early life onwards. Surprisingly, LPA was found to be potentially two to three times more effective than MVPA in this regard. These results highlight the potential of LPA as an unsung hero in safeguarding against diseases, particularly in the context of cardiovascular health.

Agbaje further explains that while the World Health Organization has stressed the importance of children and adolescents getting an average of 60 minutes of moderate-to-vigorous physical activity (MVPA) per day and reducing sedentary time, there is a lack of guidelines regarding light-intensity physical activity (LPA) for the younger population due to limited data. However, our recent studies are contributing to the growing body of evidence in this area. Therefore, it is crucial for public health experts, pediatricians, and health policymakers to promote increased engagement in LPA from early childhood onwards. Nevertheless, more research is required to establish the health benefits of LPA and provide sufficient evidence for updating current health guidelines.

urFIT-child, the research group led by Dr. Agbaje, receives support from various research grants. These grants are provided by esteemed organizations such as the Jenny and Antti Wihuri Foundation, the Finnish Cultural Foundation Central Fund, the Finnish Cultural Foundation North Savo Regional Fund, the Orion Research Foundation, the Aarne Koskelo Foundation, the Antti and Tyyne Soininen Foundation, the Paulo Foundation, the Yrjö Jahnsson Foundation, the Paavo Nurmi Foundation, the Finnish Foundation for Cardiovascular Research, Ida Montin Foundation, and the Foundation for Pediatric Research. These funding sources play a crucial role in enabling and facilitating the research conducted by urFIT-child in the field of child health and physical activity.