Higher baseline levels of physical activity and participation in sports among young children were associated with fewer days of symptoms from upper respiratory tract infections (URTIs) such as the common cold, a cross-sectional study from Poland showed.
In kids ages 4 to 7 years, as the average daily number of steps taken increased by 1,000, the number of days they experienced symptoms of URTIs, most commonly cough and runny nose, decreased by an average of 4.1 days over the study period, reported Wojciech Feleszko, MD, PhD, of the Medical University of Warsaw, and co-authors.
Moreover, the average daily step count on healthy days, measured in the study by a pedometer armband, was found to be a “significant determinant” of the total number of days with symptoms, independently accounting for 43.5% (P<0.001) of this variable variance, they noted in Pediatric Research.
In addition, the average daily step count on healthy days and regular participation in sports were significantly associated with the total number of days with URTI symptoms, such that fewer days with symptoms were observed in children who regularly participated in sports and had more daily steps.
Among those who didn’t participate in sports, there was a significant correlation between average daily step counts on days in which no symptoms were reported and the total number of days experiencing URTI symptoms (r= -0.73, P<0.001). However, there was no significant correlation among children who regularly participated in sports (r= 0.06, P=0.839).
Feleszko and colleagues also noted that the severity of symptoms was inversely associated with the average number of daily steps in the non-sport group, but not in the sports group.
According to a 2022 U.S. study, URTIs account for over 20 million days of both missed work and school, and an estimated 10 million outpatient appointments a year.
“Pre-school children (up to 6 years of age) are especially vulnerable to infections due to their immature immune and respiratory systems,” Feleszko and team wrote. “Even in the absence of any primary pathological condition, they experience numerous episodes of URTIs. Though generally mild and resolving spontaneously, such episodes can affect the patient’s quality of life, cause parental distress, and in the long-term, lead to family dysfunction, occupational disruption, and healthcare burden.”
The researchers cited many reasons for increased risk of URTIs among children, including individual factors such as asthma and allergies, as well as environmental factors like air pollution and childcare/educational facilities, where many children are present at one time.
“The mechanisms responsible for the observed association between PA [physical activity] and URTI frequency in children have not been thoroughly researched and described so far. Regular PA may reduce the levels of inflammatory cytokines, thus reducing the effects of the chronic inflammatory process related to aging and chronic disease,” they noted.
They called for further research to determine the mechanisms by which physical activity helps to reduce the duration of URTI symptoms.
“Parents of pre-school children should encourage their wards to engage in PA every day, creating opportunities and possibilities for PA involving entire families, especially if their children do not regularly participate in sports activities,” they concluded.
For this study, which was conducted from December 2018 to March 2019, Feleszko and colleagues included 104 children (mean age 5.3 years, 55 girls) who were given activity trackers, which measured average exercise intensity, sleep time, and daily step count, to be worn all day for 40 days. Parents and guardians helped the kids complete a set of 60 questionnaires, one daily, to assess URTI symptoms, using the Polish version of the validated Wisconsin Upper Respiratory System Survey for Kids.
Of the children, 64.4% had siblings, 7.7% had been exposed to passive smoking, and 42.3% had been exposed to pet hair. Regular vaccination was confirmed by 93.3% of parents.
The median total number of days with URTI symptoms in the study group was 26 days, for a 60-day observation period, which the researchers said is typical for this season and age group.
Median sleep duration was 10.4 hours, but no correlation between sleep and symptom duration was observed.
Furthermore, participant sex, vaccinations, exposure to smoking or pet hair, and number of siblings had no effect on the duration of URTI symptoms.