Jet Lag, Sleep Debt and Melatonin: The Hidden Cost of Crossing Time Zones
After 11 days of intense travel in Europe, Bryan Johnson tracked how time-zone shifts eroded his sleep, willpower, mood and food choices day by day. With Dr. Mike Mallin he works through the evidence — from Olympic medal outcomes to a soccer-team trial — and lands on a surprising conclusion: the protocols shorten jet lag but never prevent it, so the real lever is travelling less. The episode ends with a practical travel budget and the five basics worth doing every trip.
Overview
Bryan Johnson opens the episode without co-host Kate Tolo, who is sick after the same 11-day European trip — a fitting illustration of the topic. He describes running the trip as a deliberate experiment: later nights, less sleep, back-to-back events, and a daily accounting of what happened to his body. The decline was cumulative — brain fog, irritability, cravings for salty and calorie-dense foods, and by day ten what he calls an animalistic, primal state in which willpower had effectively gone to zero.
Dr. Mike Mallin frames the biology: the circadian system is driven mainly by blue light hitting the back of the eye, with meal timing, exercise and temperature as secondary levers, and roughly one day of adaptation is needed per hour of time-zone shift. The pair review the evidence on harm — elevated markers linked to metabolic and cardiovascular risk after time shifts, and an analysis of 173 Olympic teams across 15 games where athletes who had not yet adapted appeared to slip from gold to silver.
They also look at a small non-controlled trial in an Argentinian soccer team where timed melatonin, timed daylight and timed exercise compressed a twelve-hour shift into a little over two days. The conversation then turns to something rarely discussed: a travel budget. They sketch tiers — one three-to-four-day trip per month as the outer edge, every 60 days as middle ground, every 90 days as the safer side — and include any shift of three or more time zones, not only international flights.
Johnson's own protocol is deliberately simple: blue-light glasses and screens off on the plane, fasting and a full night's sleep in the air, then light in the eyes, breakfast and exercise on arrival, melatonin in the evening, and long naps that he found unexpectedly restorative. Mallin adds the pharmacological landscape and the case for morning cold exposure, while stressing that every intervention is marginal. The closing note is cultural: because the cost of travel has never been measured, workplaces treat unlimited time-zone hopping as heroism rather than as a real trade against health.
Key quotes
5Every day we felt like we lost three or four IQ points.
You default to your subjective feelings, because you don't have an accounting of what is happening inside the body.
Nine or ten days of short sleep plus the time-zone change annihilated my willpower. It took me to zero.
It's not about preventing jet lag as much as it is reducing the duration and the severity of it.
I literally became a different person in eleven days — my thoughts, my willpower, my mood.
Key ideas
9The cost of travel is real but unaccounted for
Businesses track what makes and loses money, but nobody tracks what travel costs the body. Without measurement, people fall back on how they feel — and feeling is a poor instrument here.
Light is the master switch of the circadian clock
Blue light hitting the back of the eye is the primary signal that sets the body's internal rhythm. Meal timing, exercise and temperature modulate it, but light dominates.
One day of adaptation per hour of shift
A nine-hour shift can take roughly nine days to fully resolve. Eastbound travel is generally harder than westbound because going to bed earlier is harder than staying up later.
Sleep debt rewrites food choices
Even an hour of nightly sleep loss measurably reduces decision quality and willpower. Johnson watched his own preferences drift from vegetables and legumes toward salty, calorie-dense foods.
The whole body runs on a clock, not just the brain
Hormones follow a daily rhythm — testosterone and cortisol peak in the morning — and the gut is primed for food at habitual times. Move ten time zones and every one of those schedules is out of phase.
Evening blue light delays the melatonin signal
Studies show evening blue light exposure can push melatonin release back by around 40 minutes, so the brain is not preparing for sleep when the new time zone demands it.
The Argentinian soccer team trial
In a small, non-controlled study of 22 male players, timed melatonin, controlled daylight exposure and timed exercise compressed a twelve-hour adaptation to a little over two days.
Short frequent trips resemble shift work
Three-to-four-day trips never let the body flip, which is closer to shift-work patterns associated with markedly higher long-term risk. One longer trip is generally kinder than several short ones.
A travel budget, in tiers
One short trip per month is the outer edge, one every 60 days is middle ground, one every 90 days is the safer side — and the count should include any shift of three or more time zones.
Practical takeaways
7- 1
Protect the flight 22:00
Blue-light blocking glasses on boarding, screen off, skip the meal, and aim for a full night of sleep in the air on eastbound flights.
- 2
Anchor the first morning 25:10
Get outside for daylight in the eyes as early as possible in the new time zone, then eat breakfast and exercise — three signals that say the day has started here.
- 3
Guard the evening 26:20
Start avoiding blue light about an hour before local sunset so the brain gets permission to produce melatonin on the new schedule.
- 4
Consider timed melatonin 44:00
Melatonin at local bedtime, ideally started before departure and continued for at least the first three nights, is the intervention Dr. Mallin is most confident about.
- 5
Time stimulants to the landing hour 47:00
Caffeine is reasonable after a morning arrival, but an afternoon or evening landing makes stimulants counterproductive — they push local bedtime later and lengthen the jet lag.
- 6
Try morning cold exposure 52:00
A cold shower or an ice-water face dunk in the morning can provide the alertness lift jet lag suppresses. Johnson found cryotherapy in Dubai cleared his fog for several hours.
- 7
Set the budget before the calendar fills 55:00
Decide in advance how many time-zone crossings a quarter is acceptable, and say it out loud to colleagues and investors. Boundaries only exist if someone states them.
Topics & chapters
15The Olympic medal that slipped away
An analysis of 173 Olympic teams across 15 games suggests athletes who hadn't adapted to the new time zone underperformed their potential.
Eleven days in Europe, one host missing
Kate Tolo is too sick to join after the same trip, which sets the tone for the whole conversation.
The experiment: going hard on purpose
Johnson describes deliberately staying up late and under-sleeping for 11 days while tracking everything.
Founders and the unmeasured cost
A conversation with 150 founders reveals that constant travel is culturally accepted precisely because nobody accounts for it.
Why jet lag exists at all
Humans evolved with the sun; the circadian system was never designed for a twelve-hour jump in daylight.
Day ten: willpower at zero
The progression from fatigue to fog to cravings, ending in what Johnson calls a primal state.
Hormones, gut and glucose out of phase
Dr. Mallin explains how many systems beyond sleep run on the same daily clock.
Light protocol on the plane and on arrival
Blue-light glasses, screens off, and immediate morning sunlight in the new location.
Does any of it actually work?
The Argentinian soccer team trial and the honest answer: shorter, not prevented.
The harms of repeated time shifts
Metabolic and cardiovascular risk signals, and the shift-work comparison.
Building a travel budget
Reasoning from monthly to quarterly trips, and why three time zones is the threshold.
The cultural conversation nobody is having
Why employers can ask for travel but could never ask for the risks it carries.
Johnson's actual protocol
Fasting on the plane, light-food-exercise on landing, evening melatonin, and long naps.
Stimulants, cold exposure and timing
When caffeine helps, when it backfires, and why a cold shower may be enough.
Eleven days, a different person
Closing reflections on how quickly identity shifts, and what future generations may find strange about us.