A relationship between temperature, oxygen dissolved in blood and viral infections

An investigation is made on the environmental factors that may determine the seasonal cycle of respiratory affections. The driving role of temperature is examined, for its inverse synergism with the dissolution of oxygen in human plasma. Two best-fit equations are discussed to interpolate the experimental data about the oxygen solubility and the saturation levels reached at various temperatures, referring to the value of the basic alveolar temperature. A vulnerable condition is when the airways temperature is lowered, e.g. breathing cold air, or increasing the breathing frequency. In winter, the upper airways reach lower temperatures and greater oxygen concentrations; the opposite occurs in summer. As low temperatures increase the dissolution of oxygen in plasma, and blood oxidation favours viral activity, an explanation is given to the seasonality of infections affecting the respiratory system.