Circadian Health Glossary

Core Body Temperature (CBT)

Core Body Temperature (CBT) refers to the internal temperature of the body’s vital organs, such as the brain, heart, and liver. Unlike skin or external body temperature, CBT remains relatively stable and is tightly regulated by the body to maintain optimal physiological function.

How Does CBT Relate to Circadian Rhythms?

CBT follows a circadian rhythm, fluctuating throughout the 24-hour day:

  • Lowest Point (Minima): Occurs in the early morning hours, typically around 90 to 120 minutes before persons natural wake up time, during the deepest sleep phase.

  • Highest Point: Occurs in the late afternoon or early evening, coinciding with peak alertness and activity levels.

These fluctuations are closely tied to the body’s internal clock and play a key role in regulating sleep-wake cycles.

Why Is CBT Important in Circadian Health?

  • Sleep Regulation: The drop in CBT at night signals the body to prepare for sleep.

  • Light Therapy: The timing of light exposure in relation to CBT minima influences whether circadian rhythms are delayed or advanced.

  • Performance: CBT peaks are associated with increased energy and cognitive performance, making it a key factor in understanding daily productivity patterns.

Related Definitions

sleep Minima Core Body Temperature (CBT) BIOLOGICAL RHYTHMS CIRCADIAN HEALTH