Higher levels of daily physical activity are associated with reduced susceptibility to upper respiratory tract infections such as the common cold.
Upper respiratory tract infections affect the nasal passages and throat. There are several types of infections in this category, including the common cold, sinusitis, laryngitis, and pharyngitis. Researchers analysed 104 Polish children in the Warsaw city region between 2018 and 2019 and whether activity levels impacted susceptibility to upper respiratory tract infections.
The research is published in Pediatric Research.
Analysing upper respiratory tract infections prevalence in children
Wojciech Feleszko, Katarzyna Ostrzyżek-Przeździecka and colleagues measured physical activity levels and symptoms of upper respiratory tract infections of children aged between four and seven years in Warsaw.
The participants wore a pedometer armband 24 hours a day for 40 days to measure their activity levels and sleep duration. Parents reported their children’s symptoms of upper respiratory tract infections, such as coughing and sneezing, using daily questionnaires for 60 days. A secondary questionnaire reported on vaccinations, participation in sports, whether they had siblings and their exposure to smoking and pet hair.
The researchers found that the average daily number of steps taken by children throughout the study period increased by 1,000 which led to the number of days that they experienced respiratory infection symptoms decreased by an average of 4.1 days. Furthermore, children who completed three or more hours of sport per week tended to experience fewer days with upper respiratory tract infection symptoms than those not regularly participating in sports.
Higher activity levels at the beginning of the study were associated with fewer days with respiratory tract infection symptoms during the following six weeks. Within 47 children whose average daily step count was 5,668 during the first two weeks of the study period, the combined number of days during the following six weeks that these children experienced symptoms was 947. However, in 47 children whose daily step count was 9,368, the combined number of days during the following six weeks that these children experience respiratory symptoms was 724. The authors did not identify any associations between upper respiratory tract infection symptoms and sleep duration, siblings, vaccinations, or exposure to pet hair or smoking.
More activity reduces infection risk
The researchers speculate that higher physical activity levels could minimise infection risk in children by reducing inflammatory cytokines levels, which are linked with chronic inflammation and disease and also promote immune responses involving T-helper cells.
The team also illuminated that skeletal muscles could release small extracellular vesicles that modulate immune responses following exercise. They caution that future research is required to understand the potential mechanisms in children and that the observational nature of their study does not allow for conclusions about a causal relationship between physical activity and susceptibility to infections.