Time Perception & Entrainment by Dopamine, Serotonin & Hormones
Andrew Huberman, a professor of neurobiology and ophthalmology at Stanford School of Medicine, discusses how the brain and body track time via neurochemicals like dopamine and serotonin. He covers circannual, circadian, and ultradian rhythms, offering ten science-based tools to enhance productivity, creativity, and relationships by adjusting time perception.
Deep Dive Analysis
18 Topic Outline
Introduction to Time Perception and its Importance
Circannual Rhythms: Seasonal Entrainment and Melatonin
Seasonal Hormone Fluctuations (Testosterone, Estrogen) and Light Exposure
Circadian Rhythms: 24-Hour Entrainment and Health Impacts
Ultradian Rhythms: 90-Minute Focus Cycles for Work
Three Forms of Time Perception: Present, Prospective, Retrospective
Dopamine and Norepinephrine: Overestimating Time, Increased Frame Rate
Serotonin: Underestimating Time, Decreased Frame Rate
Structuring Your Day: Rigid vs. Creative Work Based on Neurochemistry
Sleep Deprivation's Impact on Neurochemical Regulation
Trauma, Overclocking, and Memory Rate Adjustment
Dopamine, Spontaneous Blinking, and Time Dilation
Cold Exposure, Dopamine, and Perceiving Discomfort
Paradox of Fun vs. Boring Experiences in Time Perception
Novelty, Dopamine, and Retrospective Time Perception
Dopamine Release as a Marker for Time Bins
Habits, Dopamine, and Segmenting Your Day
Book Recommendation on Time Perception
6 Key Concepts
Entrainment
Entrainment is the process by which internal biological and psychological processes, such as mood or energy, are linked and matched to external environmental cues, like light-dark cycles or seasons. This synchronization helps our brain and body orient themselves in time.
Circannual Rhythms
These are annual biological rhythms that synchronize our internal processes, including mood, energy, and hormone levels (like melatonin, testosterone, and estrogen), with the changing seasons and varying day lengths. This system acts as an internal calendar within the brain and body.
Circadian Rhythms
Circadian rhythms are approximately 24-hour biological cycles that govern fundamental functions like sleep-wake cycles, alertness, and gene expression in nearly every cell of the body. They are primarily entrained by the external light-dark cycle, and their disruption can lead to significant health problems.
Ultradian Rhythms
These are biological cycles lasting about 90 minutes, which govern sleep stages and, during wakefulness, our ability to focus intensely and perform demanding mental or physical work. After roughly 90 minutes, there's a natural drop in concentration due to neurochemical changes, but these cycles can be self-initiated for productivity.
Overclocking (in Trauma)
In the context of trauma, overclocking refers to an extreme increase in dopamine and norepinephrine levels due to heightened arousal during a traumatic event. This causes a highly fine-sliced perception of time, making the event feel like it's happening in ultra slow motion, and results in a deeply ingrained, emotionally charged memory.
Frame Rate (of Time Perception)
This concept uses a camera analogy to describe how finely or coarsely our brain 'slices' the passage of time. Higher dopamine levels increase this 'frame rate' (fine slicing), making time seem to pass slower in the moment, while higher serotonin levels decrease it (coarse slicing), making time seem to pass faster.
10 Questions Answered
Whether a supplement breaks a fast depends on if it significantly increases your resting blood glucose. Most supplements, like Athletic Greens or fish oil, which contain minimal carbohydrates or sugar, are unlikely to break a fast for the majority of people.
Our bodies track seasons through 'circannual rhythms,' primarily by sensing changes in day length. Longer days with more light exposure lead to reduced melatonin, which in turn influences hormones like testosterone and estrogen, affecting mood and energy levels throughout the year.
When circadian entrainment is disrupted, people tend to underestimate how long they've been in isolated environments, and their perception of shorter time intervals (minutes or seconds) becomes significantly impaired, affecting their ability to contend with tasks.
Our brains operate in approximately 90-minute 'ultradian cycles' during wakefulness, allowing for intense focus. After about 90 minutes, there's a significant drop in the ability to concentrate due to the depletion of neurochemicals like acetylcholine and dopamine.
Higher levels of dopamine and norepinephrine lead to 'fine slicing' of time (increased frame rate), causing us to overestimate how much time has passed. Conversely, higher serotonin levels lead to a 'slower frame rate,' causing us to underestimate the passage of time.
Sleep deprivation dysregulates the daily patterns of dopamine, norepinephrine, and serotonin, making their states less cleanly defined. This contributes to feeling 'off' and a reduced ability to concentrate, partly because the sense of time passage is disrupted.
During trauma, extreme levels of dopamine and norepinephrine are released due to heightened arousal. This 'overclocking' effect increases the brain's frame rate, causing the event to be perceived in ultra slow motion and creating a deeply ingrained, often indelible, memory.
Deliberate cold exposure robustly increases baseline dopamine levels (up to 2.5x). This surge in dopamine causes a fine-sliced perception of time, making the discomfort of the cold feel like it's lasting much longer than it actually is.
Fun, varied, dopamine-rich experiences are perceived as passing quickly in the moment due to high frame rates. However, in retrospective memory, the novelty and varied events cause them to be remembered as much longer. Boring, low-dopamine experiences feel long in the moment but are remembered as short because fewer distinct 'time bins' were created.
Habits, by reliably triggering dopamine release, act as markers that segment our day into 'functional units.' The frequency and timing of these dopamine pulses, invoked by habits, literally set the frame rate for our perception of daily experience, helping us carve up our day.
25 Actionable Insights
1. Morning Light Exposure
View 10 to 30 minutes of bright light, ideally sunlight, within an hour of waking to set the fundamental layer of time perception and ensure precise circadian entrainment. Precise circadian entrainment is crucial for overall health, mental well-being, and physical/mental performance.
2. Minimize Evening Bright Light
Minimize bright light exposure to your eyes in the evening to maintain precise circadian entrainment. Disruptions to circadian entrainment can cause significant health problems, including increased cancer risk, obesity, and mental health issues.
3. Prioritize Quality Sleep
Ensure you get good quality and sufficient sleep, as disrupted sleep dysregulates the dopaminergic, noradrenergic, and serotonergic states throughout the day. This dysregulation can lead to a feeling of being “off,” impaired concentration, and disrupted time perception.
4. Utilize 90-Minute Work Cycles
Limit periods of focused, hard mental or physical work to 90 minutes or less. After approximately 90 minutes, your ability to focus significantly diminishes due to a drop in neurochemicals like acetylcholine and dopamine, making continued high-level performance difficult.
5. Early Day for Precision Tasks
Schedule tasks requiring rigid rules, precision, or clear right/wrong answers (e.g., math, accounting, physical skills, recipes) for the early part of the day. During this time, higher dopamine and norepinephrine levels create a “higher resolution brain” better suited for fine-slicing time and perceptual events, enhancing precision.
6. Late Day for Creative Tasks
Schedule creative thinking, brainstorming, and fluid tasks that are less constrained by specific outcomes for the second half of the day. The brain’s more serotonergic state later in the day is beneficial for tasks requiring flexibility in time perception and blending different ideas.
7. Implement Dopamine-Triggering Habits
Integrate specific, habitual routines at regular intervals throughout your day to leverage the dopamine system. These habits cause dopamine release, which acts as a time marker, helping to segment your day into functional units and control the frame rate of your experience.
8. Consistent Daily Eating Window
Eat your meals within a consistent time window each day, though the exact meal times can vary slightly. This practice helps entrain your internal circadian clock to the external light-dark cycle, which is vital for overall health.
9. Consistent Exercise Timing
Engage in physical activity at fairly regular times of day, ideally within plus or minus two hours from day to day. This consistency has a positive effect on circadian entrainment, linking your internal processes to external events.
10. Practice Yoga Nidra/NSDR
Practice Yoga Nidra or Non-Sleep Deep Rest (NSDR), even for short 10-minute sessions. Scientific data shows these protocols can greatly restore levels of cognitive and physical energy.
11. Increase Dopamine with Cold Exposure
Engage in cold exposure, such as cold showers or ice baths, as it can robustly increase your baseline dopamine levels by 2.5 times. This increase is long-lasting and appears to be a healthy way to boost dopamine.
12. Manage Cold Discomfort with Distraction
During cold exposure, use external cues (e.g., a metronome) or mental distractions (e.g., singing, thinking of something else) to manage discomfort. This helps to “divorce” your perception from the high-resolution experience of pain caused by increased dopamine, making the duration feel less prolonged.
13. Sunlight Exposure for Hormones
Expose your skin to sunlight for about two hours a day, focusing on areas like the upper body (arms, neck, face). This can influence your sense of well-being by increasing testosterone and estrogen through hormone pathways, even with cloud cover and sunscreen use.
14. Novel Experiences with Others
Seek out and engage in novel experiences with other people in different environments. This practice can enhance the perceived familiarity and depth of your relationships, making you feel as if you know that person much better.
15. Seek Novelty in Places
Actively seek out novel experiences in a particular place. The more varied and new experiences you have in a location, the longer you will feel you have been there and the more you will feel you know that place, influencing your time perception and memory.
16. Adopt Time-Restricted Feeding
Implement time-restricted feeding by eating within a consistent 8-10 hour window each 24-hour cycle. This practice has positive effects on gene expression, various body tissues, and can facilitate weight loss for some individuals.
17. Morning Electrolyte Intake
Dissolve one packet of electrolytes (like Element) in 16 to 32 ounces of water and drink it first thing in the morning. This ensures adequate hydration and electrolyte balance, which is critical for optimal brain and body function and prevents diminished cognitive/physical performance.
18. Electrolytes During Exercise
Drink electrolytes dissolved in water during any physical exercise. This practice ensures you maintain adequate hydration and electrolyte levels, vital for the functioning of all cells, especially neurons, and for sustaining performance.
19. Fish Oil During Fast
Ingest fish oil during a fast, as it is primarily fat (essential fatty acids like EPA and DHA) and typically does not significantly raise blood glucose. This means it is unlikely to break a fast for most individuals.
20. Pill Supplements During Fast
Take pill-type supplements, such as caffeine, vitamins, and minerals, during a fast. Generally, if these supplements do not contain sugar, significant carbohydrates, or protein, they are unlikely to raise blood glucose and break a fast.
21. Avoid Sunglasses for Light Viewing
Avoid wearing sunglasses when viewing bright light, especially morning sunlight, if it can be done safely. This allows more of the beneficial light to reach your eyes, which is important for precise circadian entrainment.
22. Intentionally Start Focus Cycles
You can intentionally initiate your 90-minute ultradian work cycles whenever you choose, rather than waiting for a natural start. This allows you to set a specific clock for when focused work begins, leveraging your brain’s capacity for intense concentration.
23. Minimize Distractions During Focus
During your 90-minute focused work cycles, actively limit all distractions, such as putting away your phone and turning off the internet. This practice helps you maximize your concentration and effectively engage with hard problems.
24. Use Habits as Day Markers
Utilize specific habits as “flankers” or markers throughout your day to segment your experience. The dopamine release associated with these habits helps to carve up your day into distinct, smaller or larger, functional units.
25. Adjust Blink Rate for Time Perception
To slow down your perception of time, consciously try to blink less; to speed it up, blink more. This is based on research showing that blink rate is related to the brain’s “frame rate” of experience, influenced by dopamine.
7 Key Quotes
Our perception of time is perhaps the most important factor in how we gauge our life.
Andrew Huberman
We can control the speed at which we experience life. We can slow things down or we can speed our experience of life up.
Andrew Huberman
The more dopamine that's released into our brain, the more we tend to overestimate the amount of time that has just passed.
Andrew Huberman
Early in the day you are a much more high-resolution camera so to speak than you are later in the day.
Andrew Huberman
Dopamine is not necessarily a molecule of reward, it's a molecule of motivation, pursuit, and drive.
Andrew Huberman
How often and when you release dopamine is actually setting the frame rate on the entire perception of everything.
Andrew Huberman
If something that you experience is fun or varied, it will feel like it goes by very fast, but later you will remember that experience as being very long. Conversely, if you are bored with something, it's going to seem like it takes a long time to go through that experience in the moment, but retroactively looking back, it will seem like that moment was very short.
Andrew Huberman
4 Protocols
Circadian Entrainment Protocol
Andrew Huberman- View 10 to 30 minutes of bright light, ideally sunlight, within an hour of waking.
- View 10 to 30 minutes of bright light, ideally sunlight, in the afternoon or around evening.
- Avoid bright light coming into your eyes in the evening.
- Engage in physical activity at fairly regular times of day (within plus or minus two hours from day to day).
- Eat within a fairly consistent time window each day.
Ultradian Work Cycle Protocol
Andrew Huberman- Initiate a 90-minute work cycle by deciding to focus on a hard problem or task.
- Limit all distractions as much as possible during this 90-minute period (e.g., put away phone, turn off internet).
- Expect a diminishment in performance and focus after about 90-120 minutes.
- If doing multiple cycles, space them by at least 2 to 4 hours.
- Limit to no more than three, and ideally one or two, such cycles per day.
Task Structuring Based on Neurochemistry
Andrew Huberman- Perform tasks requiring rigid rules, precision, and right/wrong answers (e.g., math, accounting, physical skills) in the early part of the day, when dopaminergic and noradrenergic circuits are more active, leading to higher resolution time perception.
- Perform tasks involving creative thinking, brainstorming, or fluid problem-solving in the second half of the day, when a more serotonergic state is present, which is beneficial for less constrained, more flexible approaches to time perception.
Leveraging Habits for Time Segmentation
Andrew Huberman- Place specific habitual routines at particular intervals throughout your day.
- Recognize that these habits cause a release of dopamine.
- Understand that these dopamine releases serve as markers, carving up your day into distinct 'functional units' or epochs.
- Utilize these habits to segment your day, providing clear time markers beyond just a to-do list.