Hypoxia survival variations in male and female mice as functions of chronological and environmental factors.

The inhalation by mice for 20 min of 5.5% oxygen in nitrogen, performed 29 times over 40 months, causes a mortality of 49.81%. Correlation coefficients were calculated between hypoxia mortality and different parameters: environmental--lighting, temperature, hygrometry, barometric pressure, biological--sex, age, body weight; and chronological--circadian, circannual, pluriannual. Partial correlation coefficients eliminate several interrelationships and finally point out the statistical significance of transfer from dark to light (p less than 0.001), of circadian (p less than 0.05), and of circannual (p less than 0.01) hypoxic mortality variations. Moreover, a significant (p less than 0.001) sex-related difference of mortality (males: 56.94%; females : 41.14%) was observed, independently of the environmental and chronological parameters studied.