An increase in body temperature is known as what?

An increase in body temperature is known as fever. This is a common physiological response to infection, inflammation, or illness, where the hypothalamus in the brain raises the body's set point for temperature regulation. Fever can serve as an important defense mechanism, as it can create an environment less favorable for pathogens and enhance the immune response.

The other options represent different medical conditions. Hypertension refers to high blood pressure, which is unrelated to body temperature. Hypotension indicates low blood pressure and does not pertain to temperature changes either. Malaise signifies a general feeling of discomfort or unease but does not specifically relate to a rise in body temperature. Understanding these distinctions helps to reinforce the significance of fever as a vital sign indicative of underlying health issues.