Blog — HPA Axis

Stress, Cortisol, and the Hormonal Loop of Anxiety When the body perceives danger, the brain activates the hypothalamus-pituitary-adrenal (HPA) axis — an internal alarm that releases cortisol, the body’s primary stress hormone. For short-term challenges, cortisol is beneficial. It sharpens focus, boosts energy, and prepares muscles for quick action — the classic “fight or flight” response that once ensured survival. When Stress Becomes Chronic Trouble begins when stress never switches off. Prolonged cortisol exposure interferes with healthy brain function, damaging neurons in the hippocampus (responsible for memory) and the prefrontal cortex (which governs decision-making and emotional control). As these areas...

Stress is something nearly all of us experience — in fact, 55% of Americans report feeling stressed daily, and the majority cite work or school as the primary cause. Among U.S. employees, a staggering 83% experience work-related stress, while students, from middle school to college, are increasingly feeling the pressure too. A significant number of college students even consider dropping out due to emotional strain.

Discover how saliva and blood cortisol testing reveal adrenal function and help diagnose stress-related hormone imbalances like fatigue, anxiety, and burnout.

By Dr. Tracy Tranchitella, ND (ZRT Laboratory) For anyone who has dealt with issues that are related to chronic fatigue has likely evaluated their hypothalamic–pituitary–adrenal (HPA) axis performance through a multi-point salivary test. The hormone Cortisol is measured in saliva when the samples are collected through predetermined intervals throughout a single day reveal one’s physiological resilience and metabolic reserve in response to daily stressors. HPA axis testing is a mainstay in the world of integrative, naturopathic, and functional medicine. For the past 2 years, the world has existed under the constant shadow of COVID-19. To say that we have been “stressed” is an...

When we talk about “stress,” or allostatic load, in terms of the perception of an event, we must realize that these “events” must first be translated into neurochemical signals before they trigger the HPA axis. Therefore, the sensitivity and outcome of translating these events (whether they are ongoing events, memories of past events, or stressful anticipation of unrealized events), is highly dependent upon signaling from other neurotransmitters. In fact, the signaling neurotransmitters that manage mood and affect often overlap with measures of HPA axis activation, and cannot be easily distinguished in some subjects. [1] While the detailed influence of neurotransmitters, such...