How to Defeat Jet Lag, Shift Work & Sleeplessness

Andrew Huberman, who introduces himself as a professor of neurobiology and ophthalmology at Stanford School of Medicine, frames this episode as separate from his Stanford teaching and research roles. He sets out to cover sleep and wakefulness in the context of jet lag, shift work, babies, kids and the elderly, and he promises protocols backed by "quality peer-reviewed papers, published in excellent journals." The stated goals are practical: combating jet lag, offsetting some of the negative effects of shift work, and making life easier for new parents, newborns and adolescents.

The episode builds on three previous ones about wakefulness, sleepiness, falling and staying asleep, and the roles of light, exercise and temperature. Huberman says listeners do not need that background because he will fill it in where necessary, though he recommends the earlier episodes for easier digestion of the material.

He also deliberately limits how much time he spends on harms. Rather than dwelling on what he calls "the quite valid data around depression, amnesia, dementia" linked to poor sleep, he says he wants to "focus on what you can do and arm you with tools."

The foundation of the episode is the circadian rhythm, which Huberman describes as an endogenous, or internal, roughly 24-hour rhythm in many bodily functions, most visibly wakefulness and sleepiness. His evidence comes from experiments, done rarely through history, in which people lived in a cave in constant darkness. He explains that constant darkness is easier to study than constant light because people can close their eyes. These studies show a rhythm of about 24 hours, "although it's not exactly 24 hours." Body temperature goes from low to high and back to low over that period: "Not 18, not six — 24. Plus or minus a couple hours."

Sleepiness follows the temperature rhythm. People tend to get sleepy as temperature falls and to wake as it rises. Huberman calls this a biological fact that goes "right down to our DNA," because genes in every cell keep each cell on a near-24-hour rhythm.

The master clock is the suprachiasmatic nucleus, a group of neurons he places "over the roof of our mouth." It is entrained, meaning matched, to the external 24-hour light/dark cycle set by the Earth's rotation. Through that clock, he says, cells, organs, wakefulness, temperature, metabolism, the immune system and mood are all tethered to outside light and dark. Someone who sees sunlight at sunrise, catches some light in the evening and stays in complete darkness at night would be "more or less perfectly matched" to that cycle. Huberman notes that very few people live this way because of artificial lights and "life demands," and the episode is about what happens when people are pulled away from the rhythm.

He acknowledges the familiar categories of night owls and morning larks, genetic polymorphisms that shape preferred timing, and teenagers' tendency to sleep in, and he accepts them as true. Still, he insists that "human beings are a diurnal species." His support is that many studies show people can manage a nocturnal schedule, but "serious health effects, both mental and physical, start to arise" when they drift too far from a diurnal one. He adds the caveat that he "wasn't consulted at the design phase."

Summarizing his earlier episodes and Instagram posts, Huberman reduces the ideal circadian schedule to one principle. Get as much light, ideally sunlight, into your eyes as possible during the part of the 24-hour cycle when you want to be awake and alert, and as little as possible when you want to be drowsy or asleep.

He attaches a safety qualification right away. He describes the eyes as two pieces of the central nervous system that were "extruded out of your skull," and he says that, at least with current technology, those neurons cannot be regenerated in humans. Light is too bright when it is painful to look at, or when "you have to blink or close your eyes in order to bear it," and he asks listeners not to look at lights that bright.

If you wake before sunrise, he suggests turning on artificial lights, especially overhead lights, which he says best trigger the melanopsin cells in the retina that activate the circadian clock. Once the sun is up, he argues it is present even behind clouds. He makes an exception for very dark places, such as Scandinavia in deep winter, where artificial light may be needed.

The new quantitative piece in this episode is a rule of thumb: "try and get exposure to at least 100,000 lux before 9:00 a.m.," with 10 a.m. as a looser cutoff. This assumes a wake time somewhere between 5:00 and 8:00 a.m. The mechanism he describes is cumulative. Retinal neurons signal the clock, and the system "sums, meaning it adds, photons." Huberman puts a phone or computer screen at roughly 500 to 1,000 lux and says the morning signal would not register unless you looked at it for 100 minutes or more, which is how he arrives at the 100,000 figure. At one point he phrases the target as "at least a 100,000 photons," although everywhere else he states it in lux.

You have to do it with your eyes. There is no extraocular photoreception. This is not about vitamin D in your skin.

The time limit matters because of what he calls the "circadian dead zone" in the middle of the day. Someone who wakes at eight, he says, will not get enough light from artificial sources before reaching it. He suggests measuring with a free app such as Light Meter. By his account, even bright indoor overhead lights give off only about 4,000 to 5,000 lux, while a cloudy day outside can reach 7,000 to 10,000 lux.

For places that simply aren't bright enough, he cites listeners' photos from Northern England in winter. There, he says, artificial light can be used to reach the target, and in theory the whole amount could come from artificial sources. He still holds that sunlight is the better stimulus, partly because it is free. He shows a light pad rated at about 930 to 1,000 lux, says he bought it with his own money and that its maker is not a sponsor, and points out that a cloudy day outside delivers about five times more photon energy. Such devices and selfie ring lights are useful mainly because they travel well, but he repeats that the light "has to be captured and summed before you enter the circadian dead zone."

The protocol also includes viewing sunlight around sunset, which Huberman says lowers the eyes' sensitivity. He calls the asymmetry "diabolical." Waking the system and setting the clock early in the day takes a lot of photon energy, but "it takes very little photon energy to reset and shift our clock after 8:00 p.m." He therefore advises avoiding bright light, and even not-so-bright light, between about 10:00 or 11:00 p.m. and 4:00 a.m., "as much as you safely can."

Seeing afternoon light, he argues, gives "a little bit more wiggle room" for screens and overhead lights late at night. He puts the nighttime threshold for shifting the clock at "probably only about a thousand to 1,500 lux." He refers back to his previous episode for red lights and blue blockers rather than repeating that material. He also stresses that midday sun will not shift the clock: if you wake at 10:00 or 11:00 and go out under an overhead sun, "you're not going to shift your clock."

In response to listener requests for references, he says a webpage with full links is in progress, held up partly by copyright issues. He points to two University of Colorado studies published in Current Biology, which can be found by searching "Current Biology," "camping" and "reset circadian clocks." In those studies, graduate students went camping, and two days of waking with the sun and avoiding light at night reset the melatonin and cortisol rhythms of people whose rhythms had drifted far from natural.

He mentions that regular exercise and meal timing can also shift and reinforce the clock, but he says those are not the focus of this episode.

Huberman widens the definition of jet lag beyond air travel. He says many listeners are jet-lagged because they look at their phones in the middle of the night, wake at different times each day, or exercise on a "chaotic regime." He adds that if such a pattern works for someone, "great." His promised approach is to narrow the topic to "one very specific parameter" that people can work out without technology or devices.

He spends some time on the limits of generalizing. Some people seem fine on four hours of sleep or after flying to Europe, just as some people can eat anything and keep good lipid profiles and body weight. He admits he doesn't know whether a small dietary slip really throws others off. He reports that he personally suffered badly from jet lag in certain directions of travel but not others. Some people crash after a good first day and night, and others struggle mainly on the way home. He attributes part of this variation to age and part to genetics.