Immunosurveillance associated with upper respiratory symptoms in elite swimmers: The 8-month period leading into Commonwealth Games.

OBJECTIVES: To monitor individual mucosal immunity and identify potential risk factors of upper respiratory symptoms in elite swimmers over a competitive season. DESIGN: Eight-month longitudinal study, observing mucosal immunity, Epstein-Barr virus status, training loads and illness symptoms of elite international swimmers, leading into the Commonwealth Games 2018. METHODS: Participants were fourteen elite swimmers (age ±â€¯standard deviation = 19.9 ±â€¯0.8 years, height = 178.9 ±â€¯6.3 cm, and mass = 75.0 ±â€¯7.7 kg). Self-reported upper respiratory symptoms, training load and saliva samples were collected weekly. Venous blood samples were taken at study commencement to determine Epstein-Barr virus status. RESULTS: Throughout the study, 70 episodes of upper respiratory symptoms were recorded resulting in 34 days of missed training. Incidence (p = 0.001), severity (p = 0.022), and duration of upper respiratory symptoms (p = 0.001) were significantly higher during high training loads, compared to low. Eight swimmers (61 %) had evidence of past infection with Epstein-Barr virus, but this had no relationship with incidence, severity, or duration of upper respiratory symptoms (p > 0.05). Relative individual salivary immunoglobulin A concentration was 12 % lower when upper respiratory symptoms were present but was not statistically significant (p = 0.101). CONCLUSIONS: This study highlights the importance of individual athlete monitoring, to identify swimmers at increased illness risk. Identification of possible risk factors for upper respiratory symptoms, such as increased training load, may allow for modifications in training or other illness preventative strategies for elite swimmers.

Physical activity and sitting time changes in response to the COVID-19 lockdown in England.

To reduce the spread of the novel coronavirus disease 2019 (COVID-19), national governments implemented measures to limit contact between citizens. This study evaluated changes in physical activity and sitting in response to the first COVID-19 lockdown in England and factors associated with these changes. A cross-sectional online survey-based study collected data from 818 adults between 29 April and 13 May 2020. Participants self-reported demographic information, physical activity and sitting for a 'typical' week before and during lockdown. Participants were grouped into low, moderate and high physical activity, and low and high (≥8 hours/day) sitting. Paired samples t-tests compared physical activity (MET-min/week) before and during lockdown. Pearson's Chi-squared evaluated the proportion of participants in the physical activity and sitting categories. Logistic regression explored associations of demographic and behavioural factors with physical activity and sitting during lockdown. Walking and total physical activity significantly increased during lockdown by 241 (95% confidence interval [CI]: 176, 304) MET-min/week and 302 (CI: 155, 457) MET-min/week, respectively (P < 0.001). There was a 4% decrease in participants engaging in low physical activity and a 4% increase in those engaging in high physical activity from before to during lockdown (P < 0.001). The proportion engaging in high sitting increased from 29% to 41% during lockdown (P < 0.001). Lower education level (odds ratio [OR] = 1.65, P = 0.045) and higher BMI (OR = 1.05, P = 0.020) were associated with increased odds of low physical activity during lockdown, whereas non-White ethnicity (OR = 0.24, P = 0.001) was associated with reduced odds. Younger age was associated with increased odds of high sitting (OR = 2.28, P = 0.008). These findings suggest that physical activity and sitting both increased during lockdown. Demographic and behavioural factors associated with low physical activity and high sitting have been identified that could inform intervention strategies during situations of home confinement.