Is Exercise Protective Against Influenza-Associated Mortality?

Abstract

BackgroundLittle is known about the effect of physical exercise on influenza-associated mortality.Methods and FindingsWe collected information about exercise habits and other lifestyles, and socioeconomic and demographic status, the underlying cause of death of 24,656 adults (21% aged 30–64, 79% aged 65 or above) who died in 1998 in Hong Kong, and the weekly proportion of specimens positive for influenza A (H3N1 and H1N1) and B isolations during the same period. We assessed the excess risks (ER) of influenza-associated mortality due to all-natural causes, cardiovascular diseases, or respiratory disease among different levels of exercise: never/seldom (less than once per month), low/moderate (once per month to three times per week), and frequent (four times or more per week) by Poisson regression. We also assessed the differences in ER between exercise groups by case-only logistic regression. For all the mortality outcomes under study in relation to each 10% increase in weekly proportion of specimens positive for influenza A+B, never/seldom exercise (as reference) was associated with 5.8% to 8.5% excess risks (ER) of mortality (P<0.0001), while low/moderate exercise was associated with ER which were 4.2% to 6.4% lower than those of the reference (P<0.001 for all-natural causes; P = 0.001 for cardiovascular; and P = 0.07 for respiratory mortality). Frequent exercise was not different from the reference (change in ER −0.8% to 1.7%, P = 0.30 to 0.73).ConclusionWhen compared with never or seldom exercise, exercising at low to moderate frequency is beneficial with lower influenza-associated mortality.

A Review of the Evidence to Support Influenza Vaccine Introduction in Countries and Areas of WHO's Western Pacific Region

“…All the studies were conducted in the general population. Research was conducted on hand hygiene [107], [108], infection control [109], facemask use [108], [110], school closure [111], [112], physical exercise [113], alternative therapies including tea catechin [114], passive immunotherapy for management of severe cases of influenza infection [115] and use of traditional medicine [116]. One modelling study assessed methods to improve the effectiveness of different antiviral strategies [117], and another evaluated combinations of methods including enhanced surveillance with isolation, segregation and personal protective equipment to limit influenza transmission in closed environments [118].…”

Relationship between community prevalence of obesity and associated behavioral factors and community rates of influenza‐related hospitalizations in the United States

“…Previous research, mainly focusing on populations in developing nations, linked malnutrition and micronutrient deficiency with respiratory infection 55 , 56 , 57 , 58 . Several studies also demonstrated benefits of chronic moderate exercise in stimulating immune function and increasing serum concentrations of vitamin D (25 (OH) D) 59 , 60 , 61 . Due to limitations in data availability, we only considered specific definitions of poor diet and physical inactivity but other forms of malnutrition and physical inactivity may also play a role.…”

Exercise and Respiratory Tract Viral Infections

“…An early study published by Heath et al (11) found runners in the upper two quartiles of yearly mileage (>866 miles run during the 12 month follow-up period) had a significantly higher risk of self-reported upper respiratory tract infection (URTI) symptoms compared to runners in the lowest quartile (<486 miles). A recent study found low-to-moderate frequency of exercise reduced the risk of influenza-associated mortality in adults living in Hong Kong during 1998, while a high frequency of exercise (>4d/week) failed to reduce the risk of mortality when compared to the sedentary referent group (34). A retrospective study by Kostka et al (14) found no relation between fitness level and self-reported weeks with URTI symptoms, although energy expenditure during leisure-time sports was significantly negatively correlated with total weeks of URTI symptoms as well as with number of episodes of URTI during a 1 year period.…”

“…Sedentary persons are considered to be at normal risk of URTI. Exercise of low-to-moderate intensity or frequency is associated with reduced risk of URTI (3,18,23,25,34) while high-intensity exercise is associated with an increased risk of infection (8,11,24). [Adapted from Nieman DC, Johanssen LM, Lee JW.…”

“…Cross-sectional and longitudinal data suggests persons who engage in regular moderate intensity exercise maintain a reduced risk of self-reported respiratory symptoms (14,18,23,34). Additionally, work from our laboratory and others demonstrates moderate intensity exercise performed prior to infection (6) or infectious symptoms (15) reduces respiratory virus-associated mortality in animals.…”