Cortisol is a steroid hormone produced and released by the adrenal glands, small organs atop each kidney. It is recognized as the body’s primary stress hormone, involved in the “fight or flight” response. Beyond stress, cortisol influences numerous bodily processes: metabolism, inflammation, and the sleep-wake cycle.
The Body’s Natural Cortisol Cycle
Cortisol exhibits a distinct 24-hour circadian rhythm, a regular daily pattern that helps synchronize the body’s functions with day and night. For most individuals, cortisol levels begin to rise in the second half of the night, peaking in the early morning, typically between 7:00 and 9:00 AM. This morning surge, often referred to as the cortisol awakening response, helps individuals wake up and mobilize energy for daily activities. Normal morning salivary cortisol levels can range from approximately 10.2-27.3 nanograms per milliliter (ng/mL).
Following its morning peak, cortisol levels gradually decline throughout the day and into the evening. They reach their lowest point around midnight or during the early hours of sleep, sometimes becoming nearly undetectable. This natural decline allows the body to wind down and prepare for rest, contributing to the sleep-wake cycle. This rhythmic pattern is regulated by the hypothalamic-pituitary-adrenal (HPA) axis, a complex system involving the brain and adrenal glands, which helps maintain overall bodily balance.
Acute Increases in Cortisol
Beyond its daily rhythm, cortisol levels can experience temporary, short-term increases in response to specific situations. Physical stressors, such as intense exercise, illness, injury, or surgery, can trigger a rise in cortisol as the body works to cope with the demand. Psychological stressors, including anxiety, fear, public speaking, or navigating deadlines, also prompt the adrenal glands to release more cortisol. This response provides the body with readily available glucose for energy and temporarily suppresses functions not immediately necessary for survival.
Lack of adequate sleep can also lead to acute spikes in cortisol levels, disrupting hormonal balance. Cortisol’s temporary elevation helps allocate resources, making it an adaptive mechanism for short-term survival. These acute increases are a normal part of the body’s protective system. However, the duration and frequency of these spikes can influence overall health.
Sustained High Cortisol
When cortisol levels remain elevated for extended periods, it can move beyond an adaptive response and begin to affect various bodily systems. Chronic psychological stress is a common cause of persistently high cortisol, as the HPA axis remains activated over time. Certain medical conditions also contribute to sustained high cortisol, including Cushing’s syndrome, which can result from adrenal gland tumors or pituitary gland issues that cause excessive cortisol production. Chronic pain and severe depression are other conditions that may be associated with elevated cortisol levels.
Long-term use of corticosteroid medications, such as prednisone, can mimic the effects of naturally produced cortisol, leading to chronically high levels. Sustained high cortisol can affect metabolism, leading to increased blood sugar and potential weight gain, particularly around the face and abdomen. It can also suppress immune function, alter mood, and disrupt sleep quality, creating a cycle where poor sleep further elevates cortisol.
Managing Cortisol Levels
Implementing practical strategies can help support healthy cortisol regulation, especially when levels are consistently elevated due to lifestyle factors. Stress reduction techniques are beneficial, with practices like mindfulness, meditation, and deep breathing helping to calm the nervous system and lower cortisol. Engaging in regular, moderate exercise can also help balance hormones and reduce tension. However, overly intense exercise can temporarily raise cortisol, so finding a balanced approach is helpful.
Prioritizing adequate sleep hygiene is important, as consistent sleep schedules and a conducive sleep environment help maintain cortisol’s natural rhythm. A balanced diet rich in whole foods, fruits, vegetables, lean proteins, and healthy fats supports overall hormone balance, while avoiding excessive sugar and processed foods helps prevent cortisol spikes. Maintaining social connections and engaging in enjoyable hobbies contributes to emotional well-being and helps keep cortisol levels in check.