How Stress Affects Cortisol and Hormones: An Overview

Why This Matters to You

Stress is a common experience, with studies showing that many adults report feeling stressed regularly.¹ But understanding stress isn't just about feeling better in the moment; it also plays a role in reducing the risk of certain health conditions that can develop over time.

During stress, the body releases hormones like cortisol and adrenaline which are involved in “fight or flight” response. While this response is helpful in short-term situations, ongoing stress can lead to prolonged elevation of these hormones. Over time, this may contribute to an increased risk of cardiovascular and metabolic conditions, as well as affect mental health and immune system function.

The good news is understanding how your stress response works can help you manage it effectively. Lifestyle changes and stress management techniques may help reduce the impact of stress.

What Is Cortisol, and Why It Matters

Cortisol is a hormone produced by the adrenal glands, located above the kidneys. It is often referred to as the “stress hormone,” although this only describes part of its role.

It plays an essential role for normal body function, including regulation of blood pressure, blood sugar levels, and metabolism. However, problems arise when cortisol levels remain elevated over prolonged periods.

The Normal Daily Cortisol Rhythm

Cortisol follows a daily pattern that helps regulate energy levels and body functions.

 Figure 1: Your body's natural cortisol rhythm peaks in the morning and gradually declines through the day, allowing sleep at night. This cycle is essential for regulating energy, mood, and sleep quality.²

Morning (6-8 AM): Cortisol levels typically peak shortly after waking, helping to promote alertness for the day ahead.

Throughout the day: Cortisol levels gradually decline from mid-morning, continuing to decrease throughout the afternoon and into the evening.

Evening and night: Cortisol levels are lowest at night, which allows melatonin levels to rise and supports sleep onset.

This daily rhythm is controlled by a small area in the brain (suprachiasmatic nucleus) that acts as the body’s internal clock. Disrupting this rhythm—through shift work, irregular sleep, or ongoing stress—can affect sleep, energy, immunity, and mood.

How Your Stress System Works (HPA Axis)

When you experience stress, the body activates a coordinated response known as the hypothalamic–pituitary–adrenal (HPA) axis. This is a communication system between the brain and hormone-producing glands that helps regulate the stress response.

Brain detection and coordination (Hypothalamus)

Stress signals begin in the brain, where the amygdala helps detect potential threats and the hypothalamus coordinates the body’s response.

Hormone signalling (Pituitary Gland)

The hypothalamus sends signals to the pituitary gland, a small hormone-producing gland in the brain. In response, the pituitary releases a chemical messenger into the bloodstream that travels to the next stage of the system.

Hormone release (Adrenal Glands)

The signal reaches the adrenal glands, which release cortisol and other stress hormones into the bloodstream.

This process occurs within minutes and prepares the body for action by increasing heart rate, raising blood pressure, and making energy more readily available.

The Body’s Built-In Regulation System

The stress response includes a feedback system that helps regulate hormone levels. As cortisol levels rise, they signal the brain to reduce further hormone release, helping restore balance.

In most cases, after a short-term stress event, cortisol levels return to baseline within minutes to a few hours.³ This recovery process is part of normal physiological regulation.

What cortisol does during short-term stress

When released briefly, cortisol helps the body respond effectively to stress:

• Increases the availability of glucose, providing energy for the brain and muscles
• Supports alertness and focused attention
• Raises heart rate and blood pressure, improving blood flow to essential tissues
• Helps the body respond to immediate demands
• May temporarily influence immune activity during short-term stress
• Can reduce sensitivity to pain in the short term

Why this response exists

This short-term stress response helps the body react to immediate challenges. However, it is intended for temporary activation rather than long-term stimulation.

Acute vs. Chronic Stress

The problem occurs when stress becomes ongoing.

Acute stress (short-term): a protective response

Acute stress lasts from minutes to a few hours. During this time, cortisol levels rise to help the body respond to a challenge, then return to baseline once the stressor has passed. This is a normal and adaptive response, not a harmful one.

Examples include a job interview, a minor car incident, or a difficult conversation. These situations trigger a short-term stress response, after which the body returns to baseline.

Chronic stress (long-term): ongoing activation of the stress response

Chronic stress occurs when stress is experienced over an extended period, lasting weeks, months, or longer. It may result from ongoing work pressure, financial difficulties, relationship challenges, or health-related concerns. Studies suggest that a substantial proportion of adults experience regular stress, with one survey reporting that approximately 49% of Americans experience significant daily stress.⁴

When stress becomes long-term, the body’s regulatory feedback system may become less efficient. As a result, cortisol levels may remain elevated or become dysregulated over time.

In some cases, cells may become less responsive to cortisol, a process known as glucocorticoid resistance. This may lead the body to produce higher levels of cortisol in an attempt to maintain its effects.⁵

Over time, these changes may affect how the body regulates stress.

How chronic stress may affect the body

Chronic stress has been associated with a range of physical health effects. These may help explain symptoms such as fatigue, changes in appetite or weight, difficulty concentrating, and emotional changes.

Cardiovascular System

The cardiovascular system is particularly affected by long-term stress.

 Figure 2: Chronic stress has been associated with an increased risk of cardiovascular disease, metabolic disorders, and mental health conditions.⁶

Research suggests that chronic stress may contribute to an increased risk of cardiovascular disease.⁷ Some studies have also reported an association between acute stress and heart-related events, although the exact contribution varies between individuals and contexts.⁸

Persistently elevated stress hormones may increase blood pressure over time and place strain on the cardiovascular system. It may also be associated with damage to the lining of blood vessels, inflammation, and the buildup of fatty plaques in the arteries.

Some research suggests that psychological stress may act as a contributing risk factor for cardiovascular disease, alongside factors such as smoking, physical inactivity, and diet.⁹

Weight Gain and Metabolic Effects

Chronic elevation of cortisol may influence how the body stores and uses energy.

Elevated cortisol has been associated with increased fat storage, particularly in the abdominal area (visceral fat), as well as increased breakdown of muscle tissue for energy production.¹⁰ These changes may occur even without significant changes in dietary intake.

Over time, chronic cortisol elevation may also contribute to insulin resistance, which is a known risk factor for type 2 diabetes. Some studies have reported that women with higher levels of chronic stress may have an increased risk of developing type 2 diabetes compared to those with lower stress levels.¹¹ These effects are primarily driven by hormonal and metabolic changes within the body.

Brain function and cognitive effects

The hippocampus is a region of the brain involved in memory and learning. Prolonged exposure to elevated cortisol levels has been associated with structural and functional changes in this area.¹² These changes may contribute to symptoms such as difficulties with memory, reduced attention, slower information processing, and challenges with planning and decision-making.

Chronic stress may affect emotional regulation and is associated with an increased risk of depression. Depression has been reported in a significant proportion of individuals with Cushing’s syndrome, although prevalence estimates vary between studies.¹³ These effects are linked to changes in brain function and neurochemical signalling related to prolonged cortisol exposure.

Immune System Suppression

Acute stress may temporarily enhance certain aspects of immune function, whereas chronic stress has been associated with suppression of immune responses. Elevated cortisol levels may reduce the activity of key immune cells and influence inflammatory signalling, which can affect immune function.¹⁴ These changes can make individuals more susceptible to infections, slow recovery, and delay wound healing.

In some cases, high levels of stress have been associated with faster progression of certain conditions. For example, studies in individuals with HIV have reported that higher stress levels may be linked to increased risk of disease progression, although multiple factors are involved.

Sleep disruption: a self-reinforcing cycle

Chronic stress may disrupt the normal daily rhythm of cortisol. Instead of peaking in the morning and gradually declining at night, cortisol levels may remain elevated throughout the day and evening. This can interfere with melatonin production, making it harder to fall asleep and maintain sleep.¹⁵

Poor sleep may then further increase cortisol levels, which can in turn continue to affect sleep quality, creating a self-reinforcing cycle.

Hormone effects

Chronic stress may affect multiple hormonal systems beyond cortisol.

Prolonged activation of the stress response can influence the hypothalamus and related hormonal pathways, which may affect other endocrine functions.

Thyroid function: Elevated cortisol levels may interfere with thyroid hormone regulation, including hormone production and conversion. This may contribute to symptoms such as fatigue, reduced metabolic rate, and weight changes.¹⁶

Reproductive hormones: Chronic stress may affect the production and regulation of sex hormones, including oestrogen, progesterone, and testosterone. In women, this may be associated with menstrual irregularities and reduced fertility. In men, it may affect testosterone levels and reproductive function.¹⁷

Some studies have also reported that higher levels of stress may be associated with an increased risk of infertility in women, although multiple factors are involved.

Digestive Problems

Chronic stress and elevated cortisol may affect digestive function, as the body prioritises stress responses over gut activity. This may be associated with symptoms such as acid reflux, irritable bowel symptoms, and changes in bowel habits, including constipation or diarrhoea.¹⁸

Mental health and stress

Chronic stress is strongly associated with mental health outcomes, including depression and anxiety.

 Figure 3: Mental health is commonly affected in individuals experiencing chronic stress, with studies reporting elevated rates of depression and anxiety symptoms among stressed adults. Younger adults aged 18–24 appear to be particularly affected.¹⁹

Studies in stressed adults have reported high rates of depressive and anxiety symptoms, with younger adults appearing particularly affected. Some surveys also report that a proportion of individuals experiencing chronic stress report suicidal ideation.

Chronic stress may influence brain regions involved in emotional regulation and has been linked to increased inflammatory activity, both of which are thought to contribute to mood disturbances. The relationship between stress and mental health is bidirectional, as stress can worsen mood symptoms, which may in turn increase stress perception and physiological stress responses.

Younger adults, particularly those aged 18–34, have been reported to experience higher levels of stress and related mental health symptoms compared to older age groups.²⁰

Stress Prevalence

Chronic stress is widely reported across global populations, with surveys indicating that a substantial proportion of adults experience regular stress.

 Figure 4: Stress is highly prevalent globally and affects hundreds of millions of people worldwide.²¹

Stress is highly prevalent across both national and global populations. Large-scale surveys indicate that a substantial proportion of adults in the United States and other countries report experiencing stress on a regular basis, with many stating that it affects their daily functioning.

Stress is also commonly perceived as a major public health concern in many countries, reflecting its broad societal impact.

Some studies suggest stress levels have increased over time, but results vary between populations and methods.²²

Evidence-based stress management strategies

Several interventions have been shown to help reduce cortisol levels and improve stress-related outcomes.

Meditation and Relaxation Techniques

 Figure 5: A review of multiple studies suggests that meditation, relaxation techniques, and yoga are associated with reductions in cortisol levels, with meditation and relaxation techniques showing some of the strongest reported effects among stress-reduction interventions.²³

Meditation is among the most studied interventions for stress reduction. Meta-analyses have shown that meditation and relaxation techniques are associated with modest reductions in cortisol levels and improvements in stress-related outcomes.

 Figure 6: Studies on mindfulness meditation have reported measurable physiological changes, including reductions in cortisol levels of approximately 20% in some populations, although results vary across studies.

Some studies suggest that mindfulness-based interventions may reduce cortisol levels, although the magnitude of effect varies between studies. Greater benefits have been observed in programmes with longer duration and consistent practice.

Relaxation techniques, including progressive muscle relaxation, guided visualisation, and gentle stretching, have also been associated with similar benefits and may be suitable alternatives for individuals who find formal meditation challenging.

Yoga

Yoga has been studied as a form of physical activity that may help reduce cortisol levels and improve stress-related outcomes.²⁴ Regular yoga practice has been associated with reductions in cortisol and improved stress recovery, although the magnitude of effect varies between studies.

Some evidence suggests that consistent participation may contribute to measurable changes in cortisol levels over time. Specific yoga practices have been investigated in some studies, although most research evaluates yoga as a combined intervention rather than individual poses.

Different styles and intensities of yoga have been investigated, including heated yoga, which in some studies has been associated with reduced cortisol reactivity compared to control groups.

General Exercise

Regular physical activity has been associated with reductions in baseline cortisol levels and improvements in stress-related outcomes.²⁵

Exercise intensity may influence these effects. Low-to-moderate intensity exercise has been associated with reductions in circulating cortisol, while higher-intensity exercise may temporarily increase cortisol during activity but may contribute to improved stress regulation over time.²⁶

Overall, consistent and sustained physical activity appears to be important for achieving these benefits.

Sleep Quality

Sleep plays an important role in cortisol regulation. Some studies suggest that sleep quality may be more closely associated with cortisol patterns than total sleep duration.²⁷

Poor sleep quality has been linked to alterations in cortisol rhythms, including a flatter daily pattern, regardless of total sleep time.

Adequate sleep quality and regular sleep–wake patterns may support healthier circadian regulation and cortisol balance, although findings vary between studies.

Ashwagandha: Supplement with Evidence

Ashwagandha has been studied as a supplement for stress reduction. Some meta-analyses have reported reductions in cortisol levels compared to placebo, although the magnitude of effect varies between studies. If you prefer a supplement, ashwagandha has solid research backing.²⁸

Doses used in studies typically range between 500–600 mg daily, with effects observed over several weeks of supplementation. Certain standardised extracts have been evaluated in clinical trials, although findings are not uniform across all formulations. Ashwagandha is generally well-tolerated in the short term, with mild side effects reported in some individuals.

While some studies suggest reductions in cortisol levels, the effect on perceived stress is less consistent, indicating that physiological and subjective responses may differ.²⁹

Social Connection

Social relationships have been associated with stress regulation and cortisol levels. Evidence suggests that the quality of social connections may be more closely related to stress outcomes than the size of one’s social network.³⁰

Supportive social interactions have also been linked to lower cortisol levels and improved emotional responses to stress, potentially mediated by neuroendocrine factors such as oxytocin.³¹

Maintaining meaningful social connections may therefore contribute to improved stress management and overall wellbeing.

Nutrition

Dietary patterns may influence cortisol regulation and stress-related outcomes. The Mediterranean diet has been associated with lower cortisol levels and improvements in metabolic markers in some studies.³²

Omega-3 fatty acids have also been linked to reduced inflammation and may be associated with lower cortisol levels. Foods rich in omega-3s include fatty fish, chia seeds, flax seeds, and walnuts.

Adequate intake of micronutrients such as magnesium may support stress regulation, although evidence varies.³³

Some studies suggest that dietary composition, including carbohydrate intake, may influence cortisol responses to stress; however, findings are inconsistent and should be interpreted with caution.³⁴

Nature Exposure

Time spent in natural environments has been associated with reductions in cortisol levels. Some studies suggest that short periods in nature may help reduce physiological stress responses, with greater benefits observed with regular exposure over time.³⁵

Breathing Exercises

Slow, controlled breathing techniques, including diaphragmatic breathing, have been associated with reduced physiological stress responses and may help lower cortisol levels. These techniques are often used as short-term interventions for acute stress.

Box breathing is one example of a structured breathing technique that may support relaxation.

Realistic timelines for stress-management strategies Figure 7: Different stress-management strategies may have different timeframes for effect. Some techniques, such as breathing exercises, may provide short-term relief, while others, such as meditation, may require longer periods of consistent practice.³⁶

Different stress-reduction strategies may act on different time scales, although responses vary between individuals and studies:

Short-term effects

Some interventions, such as breathing exercises, relaxation techniques, and brief nature exposure, may produce short-term improvements in stress-related physiological markers.

Short to medium term

Lifestyle changes such as regular physical activity, improved sleep, and dietary adjustments may be associated with gradual improvements in stress regulation over days to weeks of consistent practice.

Medium to longer term

Interventions such as yoga, mindfulness-based practices, cognitive behavioural therapy, and certain supplements (e.g., ashwagandha) may show measurable effects after several weeks of regular use, although outcomes vary depending on duration, adherence, and individual differences.

Overall, consistency appears to be more important than intensity, and benefits are generally greater with sustained, regular practice over time.

Where to start: practical Recommendations

Evidence suggests that stress-management strategies are most effective when they are sustainable and consistently applied.

Short, accessible practices such as diaphragmatic breathing may be useful for brief stress relief.

More time-intensive approaches, such as yoga, exercise, and meditation, may be associated with improvements in stress-related outcomes when practised regularly over time.

Dietary changes, including increased intake of omega-3 and magnesium-rich foods, have also been associated with stress-related health benefits, although effects typically develop gradually and vary between individuals.

For sleep, maintaining a consistent sleep schedule and prioritising sleep quality may support healthier stress regulation over time, with some benefits observed within days in certain studies.

For social connection, regular interaction with supportive relationships has been associated with improved stress outcomes and may contribute to both immediate and longer-term psychological benefits.

For supplements, ashwagandha has been studied at doses of 500–600 mg daily, with some trials suggesting effects after several weeks of use, although responses vary between individuals.

When to Seek Professional Support

Professional support may be helpful when stress-related symptoms persist or begin to significantly affect daily functioning.

This may include ongoing fatigue, anxiety, low mood, or sleep difficulties that do not improve with self-directed lifestyle changes over time. Individuals with pre-existing mental health conditions such as anxiety, depression, or post-traumatic stress disorder may also benefit from additional support.

Common support options include healthcare professionals such as physicians, who can assess underlying medical conditions, and mental health professionals, such as therapists or counsellors, who may use approaches like cognitive behavioural therapy. Other professionals, including registered dietitians or exercise specialists, may also provide tailored lifestyle guidance where appropriate.

Key Takeaways

Chronic stress is highly prevalent and has been associated with effects on multiple body systems, including cardiovascular, neurological, immune, metabolic, and psychological health, largely through stress-related physiological pathways such as cortisol regulation.

A range of evidence-based strategies have been studied for stress reduction, including mindfulness practices, physical activity, sleep optimisation, social connection, dietary patterns, and certain supplements. Many of these approaches are accessible and may contribute to improvements in stress-related outcomes over time.

The time course of these effects varies between interventions. Some strategies, such as breathing exercises or social support, may provide short-term relief, while others, including exercise, mindfulness, and dietary changes, typically require sustained practice over weeks to months.

Overall, consistency and long-term adherence appear to be more important than intensity, and outcomes vary between individuals.

Stress involves both psychological and physiological components, and managing it may contribute to overall health and wellbeing.

Understanding Cortisol and Stress Physiology

• Hypothalamic-Pituitary-Adrenal (HPA) Axis (Cleveland Clinic)
• Cortisol: What It Is, Function, Symptoms and Levels (Cleveland Clinic)
• Understanding the Stress Response (Harvard Health)
• Sleep and Circadian Regulation of Cortisol (National Institutes of Health)

Health Effects of Chronic Stress

• Chronic Stress Puts Your Health at Risk (Mayo Clinic)
• Impact of Chronic Psychological Stress on Cardiovascular Disease (Heart and Mind Journal)
• Elevated Stress Hormones Linked to Higher Risk of High Blood Pressure and Heart Events (American Heart Association)
• Stress-Induced Diabetes: A Review (National Institutes of Health)
• The Role of Cortisol in Chronic Stress, Neurodegenerative Diseases, and Psychological Disorders (National Institutes of Health)

Meditation and Mindfulness

• Meditation Interventions Efficiently Reduce Cortisol Levels (Health Psychology Review)
• Effectiveness of Stress Management Interventions to Change Cortisol Levels (Psychosomatic Medicine)
• Yoga, Mindfulness-Based Stress Reduction and Stress-Related Physiological Measures (Journal of Psychosomatic Research)

Exercise and Physical Activity

• The Optimal Exercise Modality and Dose for Cortisol Reduction (Sports)
• The Effects of Physical Activity on Cortisol and Sleep (Neuroscience and Biobehavioural Reviews)
• How Exercise Balances Cortisol Levels (Stanford)

Sleep and Circadian Rhythm

• Daily Associations Between Salivary Cortisol and Sleep (Sleep Journal)
• The Effect of Acute Sleep Deprivation on Cortisol Level (Journal of Clinical Medicine)

Nutrition and Diet

• Long-Term Green-Mediterranean Diet May Favour Fasting Morning Cortisol (National Institutes of Health)
• Increasing Dietary Carbohydrate as Part of a Healthy Whole Food Diet Intervention Dampens Cortisol Changes (Nutrients)

Supplements: Ashwagandha

• Effects of Ashwagandha Supplements on Cortisol, Stress, and Anxiety Levels in Adults (National Institutes of Health)

Social Connection and Mental Health

• Social Connectedness and Hair Cortisol in Community-Dwelling Older Adults (National Institutes of Health)
• Stress and Mental Health: Facts and Statistics (Mental Health Foundation)
• Anxiety Disorders: Facts and Statistics (Anxiety and Depression Association of America)

Breathing Techniques and Psychophysiology

• A Novel Wim Hof Psychophysiological Training Program to Reduce Stress Responses (Journal of Applied Physiology)
• Sleep and Circadian Regulation of Cortisol: A Short Review (Sleep Medicine)

Global Stress Statistics

• Stress Statistics 2026: How Common Is It? (SingleCare)
• Continuous Worsening of Population Emotional Stress Globally (BMC Public Health)
• What the Latest Reports Say About Stress in America (American Institute of Stress)