Effects of Physical Activity and Sleep on Respiratory Infections
Overview of the Common Cold
A recent article in PLOS One explores how physical activity and sleep influence the incidence of respiratory infections, particularly the common cold. This widespread ailment affects many individuals throughout their lives, typically presenting with mild and transient symptoms. Consequently, the broader health-related costs and outcomes associated with the common cold are often overlooked. As the most common type of upper respiratory tract infection (URTI), colds are a leading cause of visits to general practitioners in Nordic countries. Additionally, research indicates that colds significantly contribute to absenteeism from work and reduced productivity. Despite their seemingly benign nature, common colds impose a notable burden on society, warranting further investigation.
Investigating Protective Factors Against Colds
Evidence from studies conducted in Sweden and the United States suggests that individuals who engage in regular exercise or maintain high levels of physical activity may experience fewer colds and URTIs compared to those with sedentary lifestyles. Conversely, a comprehensive study from Finland and a Cochrane systematic review encompassing 11 trials reported no significant link between physical activity and the risk of catching a cold. The relationship between sleep and the likelihood of contracting the common cold also shows some potential influence, though findings remain inconclusive. To clarify these conflicting results, researchers from Sweden initiated a large cohort study to investigate the impacts of physical activity, sleep duration, and sleep quality on respiratory infections, with findings published in PLOS One.
Study Design and Findings
Participant Recruitment and Data Collection
Residents of the Eskilstuna municipality in Sweden were invited to participate via mail, resulting in 2,038 employed men and women enrolling in the study. Participants completed questionnaires that provided self-reported data on URTI exposure, physical activity, sleep patterns, and other relevant factors, such as smoking status, education level, and number of close contacts. Over a nine-month period, participants reported any respiratory infections they experienced, including follow-up questions to detail symptoms and a nasal swab sample for viral characterization.
Results: No Impact of Sleep or Physical Activity
The study revealed that half of the participants did not report any respiratory infections, while 31% experienced one occurrence, and 19% reported multiple infections. On average, each participant experienced one URTI annually, with a higher infection rate observed in women compared to men. Importantly, the study found no significant effect of physical activity, sleep duration, or sleep quality on the likelihood of encountering a URTI. Other factors, such as education level, number of children, and gender, were found to correlate with URTI occurrences.
Conclusions and Implications
This study concluded that there is no evidence linking self-reported physical activity or sleep habits with URTI incidence. These findings align with other research, particularly the aforementioned Cochrane systematic review that also reported no correlation. However, a limitation of the study includes the potential under-reporting of infections by participants, as they were asked to self-report immediately upon occurrence. Additionally, the research did not assess the specific episodes of URTI, potentially overlooking how physical activity and sleep might affect recovery and symptom severity. Nevertheless, this study contributes to the growing body of literature that does not find a connection between physical activity or sleep patterns and the risk of respiratory infections. Further research is essential for the scientific community to reach a consensus on whether exercise and sleep can lower the chances of contracting the common cold.
Author Information
Written by Branson Chen, BHSc
Reference
Ghilotti F, Pesonen AS, Raposo SE, Winell H, Nyrén O, Lagerros YT, Plymoth A. Physical activity, sleep and risk of respiratory infections: A Swedish cohort study. PLOS One. 2018 Jan 4;13(1):e0190270.