Self-contained breathing apparatus pressure changes with ambient temperature. As temperature decreases, the pressure inside the cylinder decreases. The relationship between the temperature and the pressure of a gas is defined by the formula "PV" = "nRT". (See Universal gas constant.) What is particularly important to understand from the formula is that the temperature is in kelvins, not degrees Fahrenheit. Consider the freezing point of water at 32 °F (0 °C, 273.15 K) and compare it to 96 °F (35.6 °C or 308.71 K; normal human body temperature is 37 °C). While 96 is arithmetically three times 32, the difference in temperature from a
Wilson's temperature syndrome to man." He also says that it is "the most common of all chronic ailments and probably takes a greater toll on society than any other medical condition." Wilson says that low thyroid symptoms and low temperatures in the presence of normal thyroid function tests are not due to hypothyroidism, and might be reversed with a few months of treatment. To distinguish this condition from hypothyroidism, he named it Wilson's (temperature) syndrome. He states that it is "especially brought on by stress" and can persist after the stress has passed. He says that the main diagnostic sign is a body