How to Defeat Jet Lag, Shift Work & Sleeplessness
Summary
Andrew Huberman breaks down the science of circadian rhythms and explains how light, temperature, exercise, and food timing can be used to shift your internal clock. The episode provides practical protocols for managing jet lag, adapting to shift work, and maintaining healthy sleep across different life stages — from newborns to the elderly.
Key Takeaways
- Your temperature minimum — the lowest point of your body temperature each day, occurring roughly 90 minutes to 2 hours before your typical wake time — is the single most important reference point for shifting your circadian clock.
- Viewing bright light in the 4 hours after your temperature minimum will advance your clock (earlier sleep/wake); viewing it 4–6 hours before will delay your clock (later sleep/wake).
- Traveling eastward is harder on the body than traveling westward because it requires falling asleep earlier, which the autonomic nervous system is less equipped to do.
- For trips of 72 hours or less, staying on your home schedule is generally preferable to attempting a full circadian shift.
- Shift workers should maintain a consistent schedule for at least 14 days, including weekends, to stabilize their circadian rhythm.
- Melatonin can help initiate sleep in a new time zone but does not help maintain sleep and has downstream effects on reproductive hormones (gonadotropin-releasing hormone, luteinizing hormone, testosterone, and estrogen).
- Non-Sleep Deep Rest (NSDR) protocols can help sleep-deprived individuals — such as new parents — maintain autonomic regulation even when continuous sleep is impossible.
- Light, temperature manipulation, exercise, and meal timing are all levers for clock-shifting, and work most powerfully in combination.
Detailed Notes
The Circadian System
- The suprachiasmatic nucleus (SCN), located above the roof of the mouth, generates a 24-hour internal clock.
- This clock is entrained to the external light-dark cycle and governs wakefulness, sleepiness, metabolism, immune function, and mood.
- Temperature is the primary signal by which the SCN synchronizes all cell types throughout the body — a unified signal interpretable by diverse tissues like pancreatic cells, neurons, and immune cells.
- Core body temperature and wakefulness are tightly linked: rising temperature → wakefulness; falling temperature → sleepiness.
Light Exposure Guidelines
- Morning light goal: Aim for exposure to at least 100,000 lux before 9:00 AM (assuming a 5:00–8:00 AM wake time).
- Outdoor light, even on a cloudy day, provides 7,000–10,000 lux — far more than most indoor lighting.
- If outdoor sunlight is unavailable (e.g., dark winters in northern regions), artificial light can substitute.
- Sunlight has special qualities that make it superior to artificial light for circadian entrainment.
- Evening sunlight (around sunset) is recommended to downregulate retinal sensitivity, making you less vulnerable to clock-disrupting light later at night.
- Avoid bright light between ~10:00 PM and 4:00 AM — the circadian system is highly sensitive to even low levels of light during this window.
The Temperature Minimum: Your Clock-Shifting Tool
- Definition: The lowest body temperature point in each 24-hour cycle, typically occurring 90 minutes to 2 hours before your average wake time.
- Example: If you wake at 6:00–7:00 AM, your temperature minimum is approximately 4:30–5:00 AM.
- You do not need to measure the actual temperature — only the time of the minimum matters.
| Timing of Light/Exercise/Food | Effect on Clock |
|---|---|
| Within 4 hours after temperature minimum | Phase advance (earlier sleep/wake) |
| 4–6 hours before temperature minimum | Phase delay (later sleep/wake) |
- Combining light, exercise, and meals amplifies the shift — you can shift the clock by 1–3 hours per day.
Jet Lag Protocols
Traveling East (e.g., California → Europe, 9-hour shift):
- Determine your temperature minimum (e.g., ~4:30–5:00 AM).
- 2–3 days before departure, begin waking at ~5:30 AM and get bright light (artificial if needed), exercise, and a meal at that time.
- This pre-emptively advances the clock before you land.
- Upon arrival, do not simply get sunlight without knowing where your temperature minimum falls in local time — doing so can shift the clock in the wrong direction.
- Eat on the local meal schedule.
Traveling West (e.g., Europe → California):
- The challenge is staying awake long enough to match local bedtime.
- Use caffeine, exercise, and bright light (natural or artificial) after your temperature peak to delay the clock and push through the afternoon fatigue barrier.
- Avoid unintended long naps (e.g., a 20-minute nap that becomes 4 hours) — this severely disrupts local schedule adjustment.
Short Trips (≤72 hours):
- Stay on your home schedule rather than attempting a full shift.
North-South Travel:
- Crossing latitudes without time zone changes causes travel fatigue, not true jet lag. No circadian shift is needed.
Melatonin
- Released from the pineal gland; signals sleepiness.
- Useful for initiating sleep in a new time zone; does not maintain sleep through the night.
- Hormonal caution: Melatonin inhibits gonadotropin-releasing hormone (GnRH) → suppresses luteinizing hormone (LH) → reduces testosterone (in males) and estrogen (in females). These effects are particularly significant during development and puberty.
- In children, melatonin is released at high, constant (non-cyclic) levels; it becomes cyclic at puberty and degrades in regularity with age.
- Huberman’s preference: behavioral tools (light, temperature, exercise) over melatonin supplementation due to larger safety margins and absence of endocrine side effects.
Temperature Manipulation for Clock Shifting
- Hot shower → cooling effect afterward = useful for certain timing strategies.
- Cold shower/ice bath → thermogenic rebound (body increases temperature) = useful for advancing wakefulness.
- Increasing body temperature tends to advance the clock; decreasing it tends to delay the clock.
Shift Work
- Key rule: Maintain a consistent schedule for at least 14 days, including weekends.
- The same principle applies to non-shift workers: avoid large schedule deviations on weekends (“social jet lag”).
- Light use during shift: View as much light as safely possible during alert/working hours; use darkness during intended sleep time.
- Apply temperature minimum logic: get light when temperature is rising; avoid light when temperature is falling.
Sleep in Special Populations
Newborns and Infants:
- Not born with a typical sleep-wake cycle; melatonin release is constant rather than cyclic.
- High melatonin concentrations relative to body size; levels effectively decrease as the child grows.
- Cyclic melatonin patterns emerge during puberty.
New Parents and Caregivers:
- When continuous sleep is impossible, focus on maintaining autonomic calm rather than fighting for perfect sleep.
- NSDR (Non-Sleep Deep Rest) protocols (e.g., yoga nidra) can help restore nervous system regulation without requiring full sleep.
- Still prioritize morning and evening sunlight when possible, even if sleep timing is disrupted.
Aging:
- Circadian rhythms become more disrupted with age, increasing vulnerability to jet lag and schedule changes.
- Even small deviations in meal timing and light exposure become more impactful.