Preschool age children who engage in high levels of physical activity are at low risk of developing upper respiratory tract infections (URTIs), according to a study from Poland published in the journal Pediatric Research.¹

Researchers from the Medical University of Warsaw and Poznan University of Physical Education, Poland conducted this study to examine if physical activity had any impact on URTIs in 104 children aged 4 to 7 years. The intensity of physical activity and duration of sleep was measured with a pedometer armband that the children wore for 40 days. The symptoms of URTIs, mainly cough and running nose, were assessed via the Wisconsin Upper Respiratory System Survey (Polish version) for children for 60 days.

Children with low levels of physical activity at baseline had greater likelihood of developing URTIs.  The number of daily steps was inversely proportional to the number of days of symptoms of URTIs. Increase in average daily step count by 1000 was associated with decline in number of symptomatic days by 4.1 days average.

Forty-seven children had an average daily step count of 5668 in the initial two weeks of the study. These children experienced URTI symptoms for a combined duration of 947 days. In another group of 47 children whose average daily step count was 9368, the combined number of days that these children had respiratory symptoms was 724. Children who engaged in sports for ≥3 hours every week also had fewer days of URTI symptoms compared to children who did not regularly play sports.

The association of sleep duration, vaccinations, exposure to smoking and pet hair and number of symptomatic days was nonsignificant.

This study reaffirms the benefits of physical activity. Preschoolers who were less physically active were more vulnerable to respiratory infections. The authors hypothesize that physical activity boosts the immune system by stimulating cellular immunity making it more robust and capable of withstanding the onslaught of infectious viruses and bacteria. It also keeps chronic inflammation in check by reducing the proinflammatory cytokines. However, the authors note that since this is an observational study, the findings do not conclusively prove a cause-and-effect association between physical activity and URTIs. Nevertheless, parents should encourage their children to be physically active and participate in sports.

The WHO recommends that children aged 2-4 years should be physically active for at least 180 minutes in a variety of physical activities at any intensity spread throughout the day. For children aged 5 years and older, the WHO recommends at least an average of 60 minutes per day of moderate-to-vigorous intensity exercise in a week.²

Reference

1. Ostrzyżek-Przeździecka K, et al. Association of low physical activity with higher respiratory tract infections frequency among pre-school children. Pediatr Res. 2023 Jan 24.  doi: 10.1038/s41390-022-02436-7.
2. https://www.who.int/news-room/fact-sheets/detail/physical-activity, dated Oct. 5, 2022. Accessed on Jan. 24, 2023.