How does the 24-hour cortisol rhythm typically function?

Cortisol should be high early in the day, shortly after waking, and gradually decline throughout the afternoon and evening, reaching its lowest point in the hours before and early in sleep. It then rises again in the final hours of sleep to facilitate waking.

What is the cortisol awakening response (CAR), and how can it be optimized?

The CAR is the sharp rise in cortisol just before and after waking, vital for alertness. To optimize it, get bright light (ideally sunlight) in your eyes within the first hour of waking, and hydrate immediately, though timing caffeine intake is also important.

How does morning light exposure impact cortisol and sleep?

Bright morning light, especially sunlight, significantly boosts the morning cortisol peak (up to 50%). A higher morning peak helps trigger the negative feedback loop that ensures cortisol levels drop sufficiently low in the evening, promoting easier sleep onset and maintenance.

Should chronic caffeine users adjust their intake to manage cortisol?

For habitual caffeine users, daily caffeine intake doesn't significantly spike cortisol but prolongs its effectiveness. Delaying caffeine intake by 60-90 minutes after waking can prevent an afternoon energy crash by making the morning cortisol decline more gradual.

Does exercise increase cortisol, and how does timing affect it?

Yes, exercise increases cortisol. However, if the type and timing of exercise are familiar, the increase is less significant. Regular exercise at a consistent time provides a strong 'entrainment cue' that reinforces the body's natural cortisol rhythm, providing anticipatory energy.

What foods can impact cortisol levels, and when should they be consumed?

Grapefruit, consumed in the morning, can extend cortisol's life by inhibiting its breakdown. Black licorice, due to glycyrrhizin, potently increases cortisol and should be consumed with caution, primarily in the morning. Starchy carbohydrates in the evening can help lower cortisol by elevating blood glucose.

How can evening lighting be optimized to reduce cortisol?

Dim indoor lights, especially overheads, in the evening, and avoid short-wavelength (blue/white) light from screens. Using red or amber lights, device red-screen filters, or special glasses can help prevent cortisol increases and melatonin suppression, aiding sleep.

What is the physiological sigh, and how can it quickly reduce stress?

The physiological sigh involves a double inhale through the nose, followed by a long exhale through the mouth until the lungs are empty. This breathing technique rapidly engages the parasympathetic nervous system, slowing heart rate and reducing stress in real-time.

How does late-day exercise affect cortisol and sleep, and how can its negative impacts be mitigated?

Intense late-day exercise can significantly spike cortisol, which can disrupt nighttime sleep and subsequent morning cortisol levels. To mitigate this, consume starchy carbohydrates after the workout, perform long-exhale breathing, take a warm shower or sauna, and avoid bright lights, especially screens.

Which supplements are recommended for reducing evening cortisol?

Ashwagandha (300-600mg) can reduce cortisol by 11-29% and should be taken in the late afternoon or evening. Apigenin (50mg), found in chamomile, also decreases cortisol. Magnesium L-Threonate or Bisglycinate can indirectly help suppress cortisol and are effective for evening use.

What are the two main patterns of burnout, and how do they differ?

Type 1 burnout involves waking up highly stressed and anxious, then crashing in the afternoon. Type 2 burnout involves feeling sluggish and tired in the morning but wired and unable to sleep at night. Each requires a different approach to regulation.

How can Non-Sleep Deep Rest (NSDR) or Yoga Nidra help with burnout?

NSDR or Yoga Nidra, practiced for 10-30 minutes, can significantly reduce cortisol levels. It's especially useful for Type 1 burnout, helping to reduce morning anxiety and regulate the steep rise of morning cortisol. It also trains self-regulation of the parasympathetic nervous system.

What is the relationship between cortisol rhythm, aging, and longevity?

As people age, particularly after 40, the morning cortisol peak can become more rounded and less steep, leading to a more gradual decline in the afternoon. This 'flattening' of the cortisol curve has been linked to reduced lifespan and poorer outcomes in health challenges like cancer. Maintaining a sharp morning peak and rapid decline is associated with better health metrics.

How to Control Your Cortisol & Overcome Burnout

Andrew Huberman

Science & Technology6 min read137 min video

Aug 4, 2025|501,621 views|14,036|851

andrew huberman huberman lab podcast huberman podcast dr. andrew huberman neuroscience huberman lab andrew huberman podcast the huberman lab podcast science podcast cortisol cortisol rhythm stress management

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Key Moments

TL;DR

Control cortisol rhythm for daytime energy, focus, mood, and stress resilience, while improving sleep quality.

Key Insights

Cortisol is an energy-deploying hormone, not just a stress hormone, vital for brain and body function.

Optimal cortisol rhythm involves high levels in the morning (spiking after waking) and low levels by evening for good sleep.

Morning sunlight exposure significantly boosts morning cortisol, anchoring the entire 24-hour rhythm.

Delayed caffeine intake (60-90 mins post-waking) flattens the afternoon cortisol decline, preventing energy crashes.

Strategic use of specific foods (grapefruit, licorice) and supplements (Ashwagandha, apigenin) can modulate cortisol levels.

Burnout manifests in two patterns (morning stress/afternoon crash or morning sluggishness/nighttime wiring), each requiring targeted cortisol regulation strategies.

Practices like physiological sigh, dimming lights, and appropriate carbohydrate intake lower evening cortisol, crucial for sleep and next-day energy.

Consistent exercise timing and novelty impact cortisol response, but regular exercise acts as a strong entrainment cue for the SCN.

Chronic elevated cortisol, especially in the afternoon/evening, is linked to health issues, cognitive decline, and reduced lifespan.

UNDERSTANDING CORTISOL: MORE THAN A STRESS HORMONE

Cortisol, often misunderstood as solely a stress hormone, is primarily responsible for deploying and directing energy to tissues throughout the body, particularly the brain. This hormone is crucial for daily functions, from waking up to engaging in demanding tasks. Produced in the adrenal glands, cortisol acts on a slower timescale than adrenaline but its lipophilic nature allows it to cross the blood-brain barrier, influencing memory via the hippocampus. A key reframe is to view cortisol as an energy-producing hormone, essential for providing the blood glucose an individual needs to operate, whether dealing with stress or simply performing daily activities.

THE 24-HOUR CORTISOL RHYTHM (CIRCADIAN CORTISOL)

The most vital aspect of cortisol regulation is its 24-hour circadian rhythm: it should be high shortly after waking and low in the hours leading up to and during sleep. This rhythm is orchestrated by the Hypothalamic-Pituitary-Adrenal (HPA) axis and the Suprachiasmatic Nucleus (SCN). Cortisol levels are minimal in the 4 hours before and 2 hours after sleep, then gradually rise during the final hours of sleep and sharply increase upon waking. This morning surge, known as the Cortisol Awakening Response (CAR), is crucial for alertness and energy but should then gradually decline throughout the day to facilitate restful sleep. This negative feedback loop ensures cortisol levels don't remain too high or too low, maintaining overall balance.

MORNING PROTOCOLS FOR OPTIMAL CORTISOL

To effectively set the daily cortisol rhythm, several morning protocols are highly recommended. Viewing bright light, ideally natural sunlight, within the first hour of waking is paramount, as it can increase cortisol levels by up to 50% and anchor the rhythm. Hydration with 16-32 ounces of water (optionally with electrolytes) upon waking also contributes to increased alertness and modest cortisol release. For habitual caffeine users, delaying intake by 60-90 minutes post-waking can prolong cortisol's effectiveness, preventing afternoon energy crashes. Regular exercise, particularly in the morning, acts as a strong entrainment cue for the SCN, further solidifying the anticipatory rise in morning cortisol and improving overall energy throughout the day.

DIETARY STRATEGIES TO MODULATE CORTISOL

Certain foods can meaningfully impact cortisol levels. Grapefruit, consumed in the morning, extends cortisol's half-life by inhibiting enzymes that break it down, thereby prolonging its effects of increased energy and focus. Black licorice, containing glycyrrhizin, can potently increase cortisol by inhibiting its conversion to cortisone, making it a strong tool for boosting morning cortisol, though caution is advised for individuals with hypertension or during pregnancy. In the evening, consuming starchy carbohydrates with the last meal of the day helps keep cortisol low by elevating blood glucose, which reduces the need for cortisol to mobilize energy, contributing to relaxation and better sleep.

EVENING PRACTICES FOR LOWERING CORTISOL

To ensure low cortisol levels in the evening and at night, crucial for sleep, several strategies should be employed. Dimming indoor lights, especially overhead and short-wavelength sources (blue/green light from screens), is vital from two hours post-sundown, as the SCN becomes highly sensitive to light's cortisol-boosting effects. Avoiding caffeine and limiting stress in the late afternoon and evening are also critical. Real-time stress reduction techniques like the physiological sigh (double inhale through the nose, long exhale through the mouth) can rapidly lower autonomic nervous system activity. Consuming starchy carbohydrates with dinner can also help maintain lower cortisol by regulating blood glucose.

SUPPLEMENTS FOR CORTISOL MANAGEMENT

While behavioral changes are primary, certain supplements can augment cortisol reduction in the evening. Ashwagandha has been shown to reduce cortisol levels by 11-29% at dosages of 300-900mg, making it suitable for evening use to promote relaxation. Apigenin, found in chamomile and often taken in capsule form (e.g., 50mg), supports cortisol reduction by acting on GABA and chloride channels, contributing to improved sleep. Magnesium Threonate can also indirectly help suppress cortisol. These supplements are best used in the late afternoon or evening to support the natural decline in cortisol, but only after foundational behavioral protocols are consistently applied.

NAVIGATING BURNOUT: IDENTIFYING AND ADDRESSING PATTERNS

Burnout is a real condition, often linked to cortisol dysregulation, and typically manifests in two patterns. The first involves extreme morning stress and anxiety, followed by an afternoon crash and evening exhaustion. The second pattern is characterized by morning sluggishness and brain fog, followed by nighttime wiring and difficulty sleeping despite exhaustion. Recognizing which pattern applies is crucial for effective intervention. Burnout is not necessarily due to adrenal failure but rather a disarray in the finely tuned cortisol rhythm, which can be corrected by applying targeted control strategies aligned with the identified pattern.

TARGETED STRATEGIES FOR BURNOUT TYPE 1 (MORNING STRESS)

Individuals experiencing burnout characterized by high morning stress and afternoon crashes need to mitigate the rapid early morning cortisol spike. Implementing Non-Sleep Deep Rest (NSDR) or Yoga Nidra immediately upon waking can help regulate the steep cortisol rise, promoting a calmer start to the day. While NSDR can induce relaxation, it's essential to still hydrate and get bright light exposure to correctly time the peak cortisol for later in the morning. Avoiding immediate caffeine intake and delaying it by 60-90 minutes will also prevent an overly sharp cortisol drop later in the day, ensuring more sustained energy without exacerbating morning anxiety.

TARGETED STRATEGIES FOR BURNOUT TYPE 2 (EVENING WIRING)

For those suffering from morning sluggishness and nighttime wiring, the focus must be on lowering evening cortisol to allow for proper morning cortisol elevation. Strict adherence to evening protocols—dimming lights, avoiding screens, and managing stress through physiological sighs—is crucial. Consuming starchy carbohydrates with dinner also helps reduce cortisol. Exercising late in the day requires additional post-workout relaxation strategies, such as long exhale breathing, hot showers, or saunas, to counter exercise-induced cortisol spikes. The goal is to create a robust cortisol nadir (lowest point) at night, allowing for a healthy and energizing cortisol surge the following morning.

THE INTERCONNECTEDNESS OF CORTISOL AND WELL-BEING

The careful regulation of cortisol's 24-hour rhythm profoundly impacts mood, focus, alertness, and sleep quality. What happens in one part of the day directly influences the others; proper morning cortisol sets the stage for a productive day and restful night, while disrupted evening cortisol can sabotage the next morning's energy. Chronic cortisol dysregulation, often seen as a 'flattening' of the cortisol curve with age or illness, is linked to cognitive decline and reduced lifespan due to the impact on the hippocampus. Maintaining a high morning peak followed by a gradual decline into a low evening trough is critical for overall health and resilience.

Mentioned in This Episode

●Supplements

●Products

●Software & Apps

●Tools

●Companies

●Organizations

●Books

●Studies Cited

●Concepts

●People Referenced

Cortisol Optimization: Daily Dos & Don'ts

Practical takeaways from this episode

Do This

View bright light (ideally sunlight) within the first hour of waking (10-30 minutes) to boost cortisol, using a 10,000 lux artificial light if sunlight isn't available.

Hydrate first thing in the morning with 16-32 ounces of water, optionally with electrolytes, to increase alertness and cortisol pulses.

For habitual caffeine users, delay caffeine intake by 60-90 minutes after waking to flatten the cortisol decline later in the day and avoid afternoon crashes.

Exercise at roughly the same time each day (within a 2-3 hour window, 3-6 days/week) to create an anticipatory rise in cortisol and boost energy for workouts.

Occasionally use deliberate cold exposure (1-2 times/week) to increase cortisol levels if desired, otherwise, use it more frequently for dopaminergic benefits.

Eat grapefruit or drink grapefruit juice in the morning/late morning to extend the life of cortisol by inhibiting its breakdown enzymes.

Dim indoor lights significantly in the evening and turn off overhead lights to prevent cortisol spikes and melatonin suppression.

Use red or amber-colored lights in the evening, and enable red screen mode on devices, or use short-wavelength light-blocking glasses.

Perform physiological sighs (double inhale through nose, long exhale through mouth) for 1-3 minutes in the evening or during stress to rapidly calm the nervous system.

Consume starchy carbohydrates with your last meal of the day to keep evening cortisol levels low and aid sleep.

Avoid This

View bright light, especially short-wavelength light from screens, in the evening or at night, as it dramatically increases cortisol and suppresses melatonin.

Ingest caffeine too late in the day (recommend cutoff 2-3 p.m.) to avoid extending cortisol's life and disrupting sleep.

Exercise intensely in the late evening, especially resistance training, without proactive measures to lower cortisol immediately afterward.

Eat black licorice if pregnant, breastfeeding, or if you have high blood pressure due to its potent cortisol-boosting and blood pressure-raising effects.

Rely solely on supplementation without establishing behavioral protocols first for cortisol regulation.

Common Questions

Cortisol's main role is to deploy and direct energy, especially glucose, to tissues like the brain. While involved in stress, it's essential for providing energy for all daily demands, including waking and focus, not just stress responses.

Topics

Adrenal Health

Mentioned in this video

supplementVitamin D3 plus K2

Supplement mentioned for its benefits across mood, brain health, heart health, and hormone status.

conceptCYP3A4

An enzyme that grapefruit compounds inhibit, responsible for breaking down cortisol and caffeine.

productROA glasses

Glasses that restrict short-wavelength light, developed in collaboration with Huberman Lab, to help reduce cortisol and prevent melatonin suppression in the evening.

drugGlycyrrhizin

A compound found in black licorice that significantly increases cortisol levels by inhibiting the enzyme 11 beta HSD. Caution is advised for its use due to potential blood pressure effects.

conceptCushing's syndrome

A medical condition characterized by hyper-elevated cortisol levels, presenting with symptoms like a rounded face and fat accumulation around the midsection.

studyendocrine responses of the stress system to different types of exercise

A scientific paper that examines how various types of exercise impact cortisol, catecholamines, inflammatory cytokines, and growth hormone.

toolDexamethasone suppression test

A medical test used to assess for Cushing's syndrome by checking if cortisol levels are suppressed the next morning after taking a cortisol-mimicking drug late at night.

supplementyohimbine

A supplement mentioned as having a modest effect in increasing cortisol.

concept11 beta hydroxy dehydrogenase (11 beta HSD)

An enzyme inhibited by glycyrrhizin, preventing the conversion of active cortisol to inactive cortisone.

personKelly Boy

Individual whose NSDR recordings are recommended by Andrew Huberman.

supplementDavid

toolYoga Nidra