Cortisol is a steroid hormone produced by the adrenal glands, which sit just above the kidneys. It is often called the “stress hormone” because cortisol levels rise when the brain perceives a threat or increased demand.
But cortisol does much more than respond to emotional stress. It helps regulate blood sugar, blood pressure, metabolism, inflammation, immune activity, sleep-wake rhythms, and the availability of energy.
Under normal circumstances, cortisol follows a daily rhythm. It is generally highest around the time we wake up and gradually declines throughout the day, reaching lower levels at night. This rhythm helps us wake up, become alert and energetic, and then wind down for sleep.
Why do we need cortisol?
Imagine you suddenly have to respond to an emergency. Your body doesn't want to devote all of its resources to digestion, reproduction, or long-term repair. It needs energy right now.
The brain activates the hypothalamic-pituitary-adrenal (HPA) axis, signaling the adrenal glands to release cortisol. Cortisol helps increase the availability of glucose in the bloodstream so the brain and muscles have fuel. It also influences cardiovascular function and temporarily alters immune and inflammatory activity.
This is an incredibly useful survival mechanism.
The problem occurs when the emergency never seems to end.
What happens with chronic stress?
Our bodies can respond to many different stressors—work and financial pressures, caregiving, relationship difficulties, inadequate sleep, illness, chronic pain, excessive exercise, calorie restriction, and psychological stress.
When stress becomes chronic, normal cortisol regulation can become disrupted. Importantly, chronic stress doesn't necessarily mean that cortisol simply remains "high" all day. The HPA axis is more complicated than that. Some people may have elevated cortisol at certain times, while others develop a flattened or otherwise altered daily cortisol rhythm.
Over time, chronic exposure to stress hormones and disrupted cortisol signaling can contribute to changes throughout the body, including:
- Blood sugar and metabolism: Cortisol increases glucose availability. Persistent stress signaling can contribute to insulin resistance and make blood-sugar regulation more difficult.
- Abdominal fat: Chronic stress and excess glucocorticoid activity can favor fat accumulation, particularly visceral or abdominal fat, although body weight is influenced by many factors.
- Sleep: Stress and abnormal evening cortisol activity can make it harder to fall asleep or stay asleep. Poor sleep can then intensify the stress response, creating a cycle.
- Blood pressure and cardiovascular health: Chronic stress can contribute to elevated blood pressure and other cardiovascular risk factors.
- Immune and inflammatory regulation: Cortisol normally helps control inflammation. Prolonged stress can dysregulate immune function rather than simply "suppressing" it.
- Brain and mood: Chronic stress can affect areas of the brain involved in memory, learning, attention, and emotional regulation and is associated with anxiety and depression.
- Muscle and bone: Persistently excessive cortisol—particularly at pathological levels, as occurs in conditions such as Cushing syndrome—can contribute to muscle loss and decreased bone density.
- Digestive health: Stress signaling can affect gastrointestinal movement, sensitivity, appetite, and the gut-brain axis. It can aggravate symptoms of conditions such as IBS, although cortisol alone isn't usually the cause.
- Reproductive function: Significant chronic stress can interfere with reproductive hormone signaling and menstrual function in some people.
The Cortisol–Blood Sugar Connection
This is particularly important when we're talking about metabolic health.
Cortisol tells the liver to make more glucose available because the body believes it may need that energy to deal with a threat. That's helpful when you're running from danger.
It's much less helpful when you're sitting at your desk worrying about something for eight hours.
If that stress response is repeatedly activated—especially when combined with poor sleep, inactivity, excess calories, or other metabolic risk factors—it can make glucose regulation more difficult.
This is one reason I believe we need to look beyond simply telling someone what to eat. Nutrition matters tremendously, but so do sleep, movement, relationships, stress management, and recovery.
Can you "lower cortisol"?
The goal shouldn't be to eliminate or continuously suppress cortisol. We need cortisol.
The healthier goal is to help restore a normal stress response and daily cortisol rhythm.
Regular physical activity, resistance training, time outdoors, adequate sleep, sufficient nutrition, relaxation practices, meditation or breathing exercises, meaningful social connection, and addressing the actual sources of chronic stress can all play a role.
Food matters here too. A predominantly whole-food, plant-forward diet can provide fiber, complex carbohydrates, healthy fats, vitamins, minerals, and phytochemicals that support overall metabolic and cardiovascular health. But there isn't one particular food, supplement, tea, or "detox" that simply switches cortisol off.
Stress Is Part of the Health Conversation
I often talk about Food as Medicine, but food is only one component of our health.
You can eat a beautiful diet and exercise regularly, but if you're chronically stressed and sleeping five hours a night, your body is still receiving signals that something isn't right.
Our bodies are constantly responding to the environment we create for them.
Sometimes improving health means adding more vegetables to our plate. Sometimes it means going for a walk, getting another hour of sleep, setting a boundary, turning off our phone, sitting quietly for ten minutes, or recognizing that we simply cannot operate in emergency mode indefinitely.
Cortisol isn't the enemy. Chronic, unresolved stress is the bigger concern.
The goal isn't a life without stress. That's unrealistic.
The goal is to give the body periods of safety, nourishment, movement, sleep, connection, and recovery so that when cortisol rises—as it is designed to do—it can also come back down.
To Health & Longevity, 🌿
Innovative Wellness
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References:
- How Stress Affects Your Health — American Psychological Association
- Cortisol — APA Dictionary of Psychology
- The Human Stress Response — Nature Reviews Endocrinology
- Understanding Chronic Stress — American Psychological Association