Gender differences in viral infection after repeated exercise stress.
Fatiguing exercise can increase susceptibility to respiratory infection after intranasal inoculation with herpes simplex virus-1 (HSV-1) in male mice. Although gender differences in susceptibility to certain pathogens do exist, it is unknown whether female mice will respond differently than males in response to strenuous exercise and HSV-1 infection.


OBJECTIVE
To test the effects of gender on susceptibility to HSV-1 respiratory infection after repeated exhaustive exercise.


METHODS
Male (N = 86) and female (N = 89) CD-1 mice (approximately 60 d old) were randomly assigned to exercise (Ex) or control (C) groups. Exercise consisted of 3 d of treadmill running at 36 m x min(-1) at 8% grade until volitional fatigue (135 +/- 5min). Fifteen minutes after the last bout of exercise, Ex and C mice were inoculated intranasally with a standard dose (LD30) of HSV-1. Mice were monitored for 21 d for morbidity (time to sickness and symptom severity) and mortality.


RESULTS
Run time to fatigue was significantly longer in females than males (P = 0.027). Significant gender differences in susceptibility to infection were found after exercise stress. In males, exercise stress resulted in increased morbidity (66%, P < 0.05) and mortality (30%, P < 0.05) whereas in females, exercise stress only resulted in increased morbidity (66%, P < 0.05).


CONCLUSIONS
Results suggest that although males and females have similar morbidity rates after infection and exercise stress, females recover to a greater extent and are ultimately better protected from death.
Brown
Adrienne S
AS
Department of Exercise Science, Arnold School of Public Health, SC, USA.
Davis
J Mark
JM
Murphy
Elizabeth A
EA
Carmichael
Martin D
MD
Ghaffar
Abdul
A
Mayer
Eugene P
EP
D000818:Animals; D004971:Estrus; D005260:Female; D018259:Herpesvirus 1, Human / Q000472:pathogenicity*; D008297:Male; D051379:Mice; D010805:Physical Conditioning, Animal; D012737:Sex Factors; D013312:Stress, Physiological / Q000503:physiopathology*