What is circadian entrainment and why is it important?

Circadian entrainment is the process by which our internal 24-hour biological clocks are synchronized with the external light-dark cycle. Precise entrainment is crucial for health, as disruptions are linked to increased risk of obesity, mental health issues, and decreased performance.

How can I improve my circadian entrainment?

Key strategies include viewing 10-30 minutes of bright light (ideally sunlight) within an hour of waking, minimizing bright light exposure in the evening, engaging in regular physical activity at consistent times, and eating meals within a regular daily window.

What are ultradian rhythms and how can they be used for productivity?

Ultradian rhythms are cycles of approximately 90 minutes. For wakeful states, these cycles relate to focus; performance tends to decrease after about 90 minutes due to reduced neurochemical support. You can leverage this by working in focused 90-minute blocks, followed by breaks.

How do dopamine and serotonin affect time perception?

Higher dopamine and norepinephrine levels are associated with 'fine-slicing' time, making events seem to happen slower and leading to an overestimation of time passed. Conversely, serotonin tends to 'batch' time, making events seem faster and leading to an underestimation of time.

Why do I feel like time speeds up when I'm having fun?

Fun and varied experiences are often associated with increased dopamine. This dopamine release causes your brain to finely slice time, making the experience feel fast in the moment, but paradoxically, you tend to remember these dopaminergic experiences as being longer due to the wealth of detailed information recorded.

How does trauma affect time perception?

During traumatic events, heightened arousal can lead to extreme increases in dopamine and norepinephrine, causing 'overclocking' where time is perceived as moving in ultra-slow motion. This can lead to memories being 'stamped down' with a fast rate code, making them difficult to process.

Can blinking affect my perception of time?

Yes, increased dopamine from heightened arousal is linked to more spontaneous blinking. Each blink acts like a shutter, slightly shifting our perception of time and contributing to overestimations of how long a period has passed. Blinking less might slow down perceived time.

How can I use habits to manage my day?

Engaging in specific habitual routines at regular intervals can act as dopamine-driven time markers. These habits can help divide your day into functional units, improving your perception and management of time by segmenting experience based on neurochemical signals.

When is the best time of day for difficult tasks?

The first half of the day, when dopamine and norepinephrine levels are typically higher, may be optimal for challenging, precision-based tasks. This state allows for finer time-slicing, enhancing cognitive ability to parse complex problems. Creative tasks might be better suited for the afternoon/evening when serotonin is more dominant.

How does cold exposure relate to time perception?

Cold water exposure is known to significantly increase dopamine levels. This increase in dopamine leads to time fine-slicing during the cold exposure, making the experience feel like it's happening in slow motion and lasting longer than it actually does.

Key Moments

Time Perception & Entrainment by Dopamine, Serotonin & Hormones

Andrew Huberman

Science & Technology6 min read75 min video

Nov 15, 2021|551,687 views|14,246|834

andrew huberman huberman lab podcast huberman podcast dr. andrew huberman neuroscience huberman lab dopamine time perception serotonin

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Key Moments

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TL;DR

Dr. Huberman explains how neurochemicals like dopamine and serotonin, and rhythms like circadian cycles, shape our perception of time, offering tools to manage it.

Key Insights

Time perception is fundamentally linked to our neurochemical state, influencing mood, stress, and how we evaluate our past, present, and future.

Entrainment synchronizes our internal biological and psychological processes with external cues, primarily through light exposure, affecting circannual, circadian, and ultradian rhythms.

Dopamine and norepinephrine "fine-slice" time, making us perceive events as slower and longer, while serotonin broadens time perception, making events seem shorter.

Morning light exposure is crucial for aligning circadian rhythms, impacting energy levels, mood, and overall physiology.

Ultradian rhythms (approx. 90-minute cycles) influence focus and performance, suggesting structured work periods for optimal productivity.

Dopamine release, often triggered by novelty and rewarding experiences, influences both present time perception and retrospective memory, making engaging events feel faster in the moment but longer in recall.

Habits can serve as dopamine-releasing time markers, helping to segment the day into functional units and improve overall time management.

THE FUNDAMENTAL ROLE OF TIME PERCEPTION

Our perception of time is a critical factor shaping our life experiences, influencing our sense of success, failure, fear, happiness, and overall outlook. Accurate time perception allows us to evaluate our past, stay on track in the present, and conceptualize our future. Understanding how this perception works offers tools to actively "dilate" or "contract" our subjective experience of time, enhancing our engagement with work, relationships, and personal well-being.

ENTRAINMENT: SYNCHRONIZING WITH EXTERNAL RHYTHMS

Entrainment is the process by which our internal biological and psychological rhythms align with external environmental cues. This alignment is crucial for maintaining physiological and psychological health. The most significant external cues are light-dark cycles, which influence circannual (yearly), circadian (24-hour), and ultradian (shorter cycles) rhythms. Disruptions to these entrainment processes can lead to significant health issues, including metabolic disorders, mental health problems, and decreased performance.

CIRCANNUAL AND CIRCADIAN RHYTHMS: THE YEARLY AND DAILY CLOCKS

Circannual rhythms, influenced by the Earth's orbit around the sun, subtly affect hormones like melatonin, testosterone, and estrogen based on day length. Melatonin, inhibited by light, is released more during shorter winter days, potentially impacting mood and energy. Circadian rhythms, governed by a master clock in the brain, are synchronized daily by light exposure, regulating gene expression and cellular activity. Consistent morning light exposure and avoidance of bright light at night are vital for maintaining a robust circadian rhythm and optimal physiological function.

ULTRADIAN RHYTHMS AND FOCUSED WORK CYCLES

Ultradian rhythms, approximately 90-minute cycles, govern periods of peak alertness and focus, followed by dips in cognitive performance. These cycles are linked to the release of neurochemicals like acetylcholine and dopamine. Leveraging these rhythms can enhance productivity; working in focused 90-minute blocks, interspersed with breaks, can optimize mental and physical tasks. It's important to initiate these cycles intentionally and space multiple cycles by several hours to avoid over-taxing neural resources.

DOPAMINE, SEROTONIN, AND THE FINE-TUNING OF TIME PERCEPTION

Our subjective experience of time's speed is modulated by key neurochemicals, primarily dopamine, norepinephrine, and serotonin. Elevated dopamine and norepinephrine lead to "fine-slicing" time, akin to increasing a camera's frame rate, causing us to overestimate time's passage and perceive events at a slower speed. Conversely, serotonin tends to broaden time perception, leading to an underestimation of time passed, essentially decreasing the frame rate. This differential effect influences our cognitive states and task suitability throughout the day.

STRUCTURING THE DAY BASED ON NEUROCHEMICAL STATES

The natural fluctuation of dopamine and serotonin throughout the day offers a framework for structuring activities. Higher dopamine and norepinephrine levels in the morning are associated with a "high-resolution" perception of time, making them ideal for tasks requiring precision, adherence to rigid rules, or complex problem-solving. Conversely, increased serotonin in the latter half of the day may be more conducive to creative work, brainstorming, and tasks that benefit from a more fluid, less precisely timed approach.

TRAUMA, AROUSAL, AND EXTREME TIME DILATION

Extreme arousal, such as during traumatic events, can lead to a powerful surge in dopamine and norepinephrine, causing significant "overclocking." This results in an ultra-slow-motion perception of events, where time is perceived as greatly dilated. While this heightened state can be adaptive in avoiding immediate danger, it can lead to deeply ingrained, emotionally charged memories. Trauma therapies often aim to re-regulate the perception of these memories, adjusting their playback rate to decouple the emotional intensity from the event itself.

BLINKING, AROUSAL, AND TIME PERCEPTION

Spontaneous blinking, often increased during heightened states of arousal, acts as a physiological "shutter" that influences our perception of time. Each blink can shift our temporal awareness, contributing to perceived time dilation, particularly when dopamine levels are elevated. This suggests that conscious control over blinking, though challenging, could potentially influence how we subjectively experience the passage of time, highlighting the intricate connection between basic physiological actions and our temporal awareness.

COLD EXPOSURE AND ITS TEMPORAL EFFECTS

Engaging in cold water immersion, such as cold showers or ice baths, robustly increases dopamine levels. This neurochemical change directly impacts time perception, making the experience of cold feel significantly longer and more intense due to the "fine-slicing" effect of dopamine. While the discomfort is real, the elevated dopamine system processes the sensation at a higher resolution, creating a perception of greater duration than the actual time elapsed. This highlights the direct link from physiological challenge to altered time experience.

PRESENT EXPERIENCE VS. PAST MEMORY OF TIME

A fascinating paradox exists between how we experience time in the moment and how we recall it later, influenced by dopamine and novelty. Fun, varied, and dopamine-releasing experiences feel shorter in the present but are remembered as being longer and more eventful. Conversely, boring or unpleasant experiences seem to drag on in the moment but are recalled as brief periods. This suggests the brain efficiently stores novel and engaging events by dilating them in memory, effectively creating a richer, longer-seeming past.

NOVELTY, DOPAMINE, AND RELATIONSHIP PERCEPTION

The interplay of novelty, dopamine, and time perception extends to our social interactions and our sense of place. Experiencing novel and varied activities in a new environment, or with new people, can make us feel as if we have been there or known that person for much longer than the actual duration. This phenomenon suggests that increased dopamine associated with novelty and varied experiences expands our subjective temporal mapping, influencing our perceived familiarity and depth of relationships or connection to a location.

NEURAL CIRCUITS AND DOPAMINE'S ROLE IN TIME SEGMENTATION

Time perception is a distributed neural phenomenon, not localized to a single brain area. However, studies using fMRI during sports viewing reveal that dopamine release in areas like the nucleus accumbens and VTA acts as a marker for segmenting time. The frequency of dopamine pulses dictates how we partition our experiences into distinct temporal units. This suggests that consciously incorporating habits that trigger dopamine release can effectively segment our day into meaningful functional blocks.

HABITS AS TIME MARKERS AND PERFORMANCE ENHANCERS

Leveraging habits provides a powerful tool for managing time perception and enhancing performance. By establishing consistent routines that trigger dopamine release, we create internal time markers that segment our day into functional units. These habits not only provide motivation and a sense of accomplishment but also serve to organize our experience by setting temporal boundaries, allowing for more deliberate task management and improved focus by capitalizing on distinct phases of our daily neurochemical rhythms.

Mentioned in This Episode

●Supplements

●Products

●Software & Apps

●Companies

●Organizations

●Books

●Drugs & Medications

●Studies Cited

●Concepts

●People Referenced

Tools and Protocols for Time Perception

Practical takeaways from this episode

Do This

View 10-30 minutes of bright light, ideally sunlight, within an hour of waking.

Get some bright light exposure again in the afternoon or evening (10-30 minutes).

Engage in physical activity at fairly consistent times daily (within +/- 2 hours).

Eat meals within a consistent time window each day.

Limit work to 90-minute cycles, with breaks in between.

Embrace novelty to make experiences feel longer in retrospect and to build familiarity with places and people.

Use habits to mark time bins and invoke dopamine release, segmenting your day.

If trying to slow down time perception, blink less.

If trying to speed up time perception, blink more (use with caution).

For creative or flexible tasks, leverage the more serotonergic second half of the day.

For precise tasks requiring adherence to rigid rules, leverage the more dopaminergic first half of the day.

Consider exposure therapies to deliberately alter the playback rate of traumatic memories.

Avoid This

Disrupt your circadian clock; avoid bright light at night.

Expect to achieve high focus immediately at the start of a 90-minute work cycle; it requires effort.

Do more than three 90-minute work cycles per day; spacing them by 2-4 hours is recommended.

Engage in highly detailed, precise tasks when feeling tired or later in the day when dopamine levels are typically lower.

Rely solely on chronological time without considering neurochemical states affecting perception.

Forget that highly arousing or traumatic events can lead to 'overclocking', causing memories to be stamped down at an accelerated rate.

Common Questions

Our perception of time is influenced by neurochemical states controlling mood and stress, and is entrained to external cycles like day length (circannual) and the 24-hour light-dark cycle (circadian). Neuromodulators like dopamine and serotonin act like internal timers, affecting how we perceive the speed of events.

Topics

Circadian Rhythm Time Perception Health & Longevity Neuroscience & the Brain Mindset & Self-Improvement Ultradian Rhythms

Mentioned in this video

Companies

ROKA

A company that produces high-quality eyeglasses and sunglasses designed for clarity in various lighting conditions.

Thorne

A supplement company partnered with Huberman Lab, known for high stringency and quality ingredients, used by major sports teams and the Mayo Clinic.

Athletic Greens

An all-in-one vitamin, mineral, and probiotic drink that Andrew Huberman has been taking for over a decade, considered a foundational supplement.

InsideTracker

A personalized nutrition platform that analyzes blood and DNA data to provide health recommendations.

Concepts

Estrogen

A hormone whose levels can vary with day length, influenced by light exposure to the skin, and is linked to energy, mood, and behavior.

PER gene

One of the 'clock genes' (period) involved in the 24-hour oscillation of gene and protein expression within cells, regulating circadian rhythms.

testosterone

A hormone whose levels can vary with day length, influenced by light exposure to the skin, and is linked to energy, mood, and behavior.

Cognitive behavioral therapies

Therapeutic approaches that may include techniques to alter the speed of memory playback to help process trauma.

EMDR

Eye Movement Desensitization and Reprocessing, a trauma therapy that may involve altering the rate of memory playback to reduce emotional load.

Norepinephrine

A neuromodulator, closely related to dopamine, that plays a role in heightened arousal states and influences time perception by increasing the brain's frame rate.

Neuron

A scientific journal that published a study on behavioral, physiological, and neural signatures of surprise during naturalistic sports viewing.

Serotonin

A neuromodulator that influences mood and can lead to underestimation of time passed by slowing down the brain's frame rate.

CLOCK gene

One of the 'clock genes' involved in the 24-hour oscillation of gene and protein expression within cells, regulating circadian rhythms.

Acetylcholine

A neurotransmitter involved in focus and alertness, which is released in cycles related to ultradian rhythms.

Dopamine

A neuromodulator that influences motivation, pursuit, and drive. Elevated levels lead to overestimation of time passed and fine-slicing of time, impacting task performance and memory.

Nucleus Accumbens

Part of the mesolimbic reward pathway in the brain, involved in releasing dopamine in response to surprise and met expectations. Also associated with time perception.

Books

Cell Reports

A scientific journal that published a study on the link between seasonal light exposure and hormone levels.

Your Brain Is a Time Machine: The Neuroscience and Physics of Time

An excellent book on time perception and its underlying neuroscience and physics, written by Professor Dean Buonomano.

Neural Network Newsletter

A monthly newsletter from the Huberman Lab that provides zero-cost information on science and tools, including protocols for improving sleep and neuroplasticity.

Current Biology

A scientific journal that published a study on the relationship between spontaneous blinking, dopamine, and time dilation.

Studies & Research

Antony et al.

Authors of a 2020 study on basketball viewing that linked dopamine release frequency to the perception of time bins and highlighted how habits can serve as dopamine-driven time markers.

Parikh et al.

Authors of a study published in 'Cell Reports' showing that skin exposure to sunlight can increase testosterone and estrogen levels, influencing mood and behavior.

European Journal of Physiology

A journal that published a study showing cold exposure can significantly increase baseline dopamine levels.

Aschoff study

A classic study from 1985, using isolated environments without time cues, demonstrated that disrupted circadian rhythms lead to underestimation of time and impaired perception of shorter time intervals.

People

Andrew Huberman

Professor of neurobiology and ophthalmology at Stanford School of Medicine and host of the Huberman Lab Podcast.

Dean Buonomano

Professor at UCLA and expert in neuroscience and physics of time, author of 'Your Brain Is a Time Machine'.

Nathaniel Kleitman

Proposed the 'basic rest-activity cycle', which describes the ultradian rhythms observed during sleep and wakefulness.

Supplements

DHA

An essential fatty acid, part of fish oil, that does not tend to raise blood glucose levels.

Melatonin

A hormone released in the brain that affects sleep and regulates hormones like testosterone and estrogen. Its release is inhibited by light.

EPA

An essential fatty acid, part of fish oil, that does not tend to raise blood glucose levels.

Cannabis

A substance that can increase serotonin levels, leading to an underestimation of the passage of time.

Drugs & Medications

Ketamine therapies

Therapeutic use of ketamine, mentioned as a treatment for trauma that might involve altering the rate of memory recall.

Organizations

UCLA

University where researcher Dean Buonomano is a professor, specializing in neuroscience and physics of time.

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