Let’s Take a Look at our Body’s “Temperature”

A healthy person’s body temperature is usually within 97.7°~99.5°F. If it is higher or lower than this, it is safe to say that it’s a sign of sickness. According to physicians and health experts, any temperature higher than 109.4°F means hyperthermia, and one may die if the temperature drops lower than 89.6°F.

The human body constantly produces heat during metabolism. 70% of the heat comes from the center of the body, while the remaining 30% comes from the skin and the peripheral tissues. The arterial blood heated from the center follows the thermal gradient and heads towards the outer body, while the cold venous blood from the outer body heads towards the center.

This whole process is monitored and controlled by our hypothalamus, which is a section of our brain that controls thermoregulation. It compares the blood’s temperature that enters the brain with the “standard blood temperature.” And if the incoming blood’s temperature is either lower or higher than the standard, it emits temperature regulating cytokines such as Interleukin 1 and thus controls the blood’s flow.

Our body shivers when cold because our muscles shrink in order to produce heat; it is part of our natural defense mechanism. On the other hand, when we are hot our peripheral blood vessels expand which allows us to sweat and release heat in our body.

Our body temperature is usually the lowest at 02:00~06:00 when we are asleep, while the highest is usually at 17:00~20:00. People who work throughout the night usually have a high body temperature during the evening and drops during the morning. Our body temperature can also rise well above the average when we exercise rigorously or when our emotions become excited. However, in areas such as our hands, feet, skin, etc., the temperature varies greatly depending on the surrounding temperature along with the body’s activity.

When our body gets sick, a chain reaction occurs where our internal temperature varies all over our body. Those suffering with high fever generally experience infection-related diseases such as cold, flu, or pneumonia. And this difference in temperature stems from the germs that infiltrate our body. The germs secrete temperature raising substances such as pyrogen, and raise our brain’s standard temperature. Moreover, those who suffer from blood cancer, stomach cancer, and lung cancer may experience chronic high fevers. And this can destroy one’s spinal cord (which can mess up our body’s temperature regulation) for those with brain tumors or brain injuries.