Why does fever increase YOUR bmr?

An elevated body temperature, or fever, does increase your basal metabolic rate (BMR). It is a natural defense mechanism that the body uses to fight off infections and pathogens. Here are a few reasons why fever increases your BMR:

1. Increased Tissue Metabolism: Fever causes an overall increase in cellular metabolism throughout the body. This elevation in cellular activity requires more energy, leading to an increase in the BMR. Various organs and tissues, including the liver, muscles, and brain, experience heightened metabolic rates during a fever.

2. Thermogenesis: The body's attempt to raise its temperature during a fever involves thermogenesis, which is the production of heat. This heat production is primarily driven by the activation of brown adipose tissue (BAT). BAT contains specialized cells called thermogenic adipocytes that burn fat to generate heat. This process of thermogenesis significantly contributes to the increase in BMR.

3. Protein Turnover: Fever can affect protein metabolism. It can increase the breakdown of proteins, known as proteolysis, particularly in muscle tissue. The energy released from the breakdown of proteins is used to support the body's defense mechanisms against infection. This increased protein turnover also contributes to the elevated metabolic rate.

4. Heart Rate and Respiration: Fever often causes an increase in heart rate and respiratory rate. The heart works harder to pump blood throughout the body, and the respiratory system speeds up to meet the increased oxygen demand. These cardiovascular and respiratory changes also contribute to the rise in BMR.

5. Hormonal Factors: During a fever, the body releases hormones such as adrenaline (epinephrine), noradrenaline (norepinephrine), and thyroid hormones. These hormones have metabolic effects that increase energy expenditure and BMR.

The extent of the increase in BMR during a fever can vary depending on the severity of the fever and individual factors such as age, overall health, and lean body mass. However, it's important to note that fever is a natural response to infection, and while it can transiently increase BMR, the body's primary focus during this time is on fighting off the underlying illness.