What does cortisol do?
Cortisol is a stimulating, alerting hormone. It’s the body’s primary stress hormone—that’s the role that gets cortisol most of its attention. Urged on by a complex network that incorporates elements of the central nervous system and the adrenal system, cortisol drives the body’s fight-or-flight response, in the presence of a threat or stressor. But cortisol does more than spur fight-or-flight. This hormone has a number of other functions, including:
  • Regulating blood pressure
  • Balancing blood sugar
  • Influencing inflammation
  • Regulating energy levels
  • Contributing to cardiac system function
  • Helping to control the sleep-wake cycle
Cortisol gets a pretty bad rap these days—and there’s no question that chronically elevated cortisol contributes to sleep disruptions and other health problems (more on those in a moment). But it’s important to be clear: cortisol is an essential component of human physiology. The challenge for many of us is to keep cortisol levels from veering too high. (As you’ll see, sleep can help with that).