THERMOREGULATION DURING SLEEP

WHAT CAUSES CHANGES IN BODY TEMPERATURE AT NIGHT?

Human beings are endotherms, which means we are able to thermo regulate, or maintain our body temperature. Body temperature is regulated through a balance of heat absorption, production and loss. Human temperature must be maintained within a fairly small range, up or down from the resting temperature of 98.6. Temperatures above 104.9 degrees Fahrenheit or below 92.3 degrees generally cause injury or death.

Humans have two zones to regulate, their core temperature and their shell temperature. The temperature of the abdominal, thoracic, and cranial cavities, which contain the vital organs, is called the core temperature. Core temperature is regulated by the brain. The shell temperature includes the temperature of the skin, subcutaneous tissues, and muscles, and it is more affected by external temperature. The core is able to conserve or release heat through the shell.

When the core temperature is too high, blood vessels in the skin dilate and heat is lost through their walls. Sweat is also produced; it evaporates and lowers temperature. If a human is too cold, the blood vessels constrict, conserving heat (gain heat from the shell).

HOW DOES BODY TEMPERATURE CHANGE THROUGHOUT THE DAY?

When you wake up, your body temperature is at its baseline of 98.6 degrees. Over the course of the morning through the late afternoon, your hypothalamus works to drive that up to 100.4 degrees. This rise in body temperature gives you energy, helping you stay alert. This partly why working out is so energizing – the rise in body heat makes you feel awake.

In the mid-afternoon, your body starts to lower your body temperature to prepare you for sleep. At 5 am, you’re at your lowest body temperature (96.4 degrees) as just before waking up.

          

TIME	BODY TEMPERATURE (DEGREES FAHRENHEIT)
6 AM	96.4
9 AM	97.8
12 PM	98.6
3 PM	99.0
6 PM	99.4
9 PM	99.2
12 AM	98.8
3 AM	98.2