Factual Blog /

How to Hack Jet Lag with 4 Simple Tools

A while back I traveled to China to visit the Factual offices in Shanghai. There was an 8 hour time difference and from experience I knew that can induce some serious jet lag.

Shortly before the trip to China I had read about a study at the Harvard Medical School suggesting that fasting while in transit may help us recover from jet lag. While working in Shanghai, I had the idea of combining this finding with other tricks I had picked up to fight jet lag. I put together a no-holds-barred approach to “hack” jet lag and decided to try it out on my trip home from Shanghai to Los Angeles.

By applying four simple tools I was able to greatly reduce the effects of jet lag. I touched down Saturday afternoon and was feeling back on PST by Monday morning.

When traveling east it can take about one day to adjust to each hour of time difference. (Apparently traveling west to east produces worse jet lag than east to west due to how our circadian rhythm works.) So that would be a solid week to adjust when coming home to Los Angeles from Shanghai. However, it took me only about 44 hours to be fully adjusted to Los Angeles time.

Here’s how I did it:

Tool #1: Sleep deprivation. Avoid sleeping in transit – this helps you fall asleep at the correct time in your new time zone.

I basically did not sleep while in transit. I waited until 10 PM PST to go to sleep the first night. That amounted to about 30 hours of no sleep from leaving the hotel in Shanghai to going to bed my first night home. That night I slept a deep, unbroken 8 hours. I guess the science here is pretty sound: once you’re sufficiently sleep deprived, it doesn’t matter what time zone your brain thinks it’s in – when you go down, you go down solid.

My goal then became to stay awake and active during the day and only sleep at night. Sunday, my first full day back, I struggled to avoid napping. Jet lag really kicked in after lunch and I ended up sleeping maybe 1 or 2 hours that afternoon. Ideally I wouldn’t have slept at all, but it seems those few hours didn’t do any real harm. After Sunday, I didn’t have any more problems staying awake during the day.

Tool #2: Natural Sunlight. Expose yourself to the natural sunlight of your new time zone.

About four hours before touching down in LA, I realized the sun was “rising” outside the plane. I opened my visor all the way and set my forehead against the window for about an hour, eyes wide open. It was roughly 10 AM PST. The idea here was to give my body a strong and natural signal that I was in a new time zone. I’ve read that the sunrise and sunset can be the most effective times to do this. Of course, this required me to have a window seat on the plane. I also lucked out with the timing – I hadn’t planned to be able to get the “sunrise” this way.

Both Saturday and Sunday I went for afternoon walks and exposed my body to the sun (which by the way felt GREAT). I especially made sure to experience the sunset on both days by standing outside for about 15 minutes in direct view of the sun going down.

The basic idea of getting natural sunlight in your new time zone seems pretty straightforward. However, later research turned up some subtle nuances:

“If you travel on an east-bound flight: - across <6 time zones, light in the morning is advised. - across 6 to 10 time zones, avoid light in the morning and get light at midday.

If you travel on a west-bound flight: - across <6 time zones, light in the late afternoon is advised. - across 6 to 10 time zones, avoid light in the afternoon and get light at midday.”

Tool #3: Drugs. Use drugs to help you sleep and help you wake up.

(WARNING: I am not a doctor. You should always consult your personal physician before taking drugs.)

I’ve always thought the most brutal aspect of jet lag is the sheer inability to fall asleep at night. Other than the self-induced sleep deprivation while in transit, my chosen weapons against insomnia were two specific drugs: sublingual melatonin and Actifed.

I consider melatonin the mild natural sleep aid, and Actifed the jack hammer. (I guess it’s the anti-histamine properties of a drug like Actifed that make you very drowsy. Admittedly there may be better solutions. I don’t have any experience with “sleeping pills”, Valium, or the like.)

Before going to sleep Saturday night, I took a maximum dose of melatonin. Perhaps I didn’t need it in order to sleep well that night – considering that I hadn’t slept in 30 hours. But melatonin is used naturally by our bodies to help regulate sleep, so my idea was that it could help reset my internal clock.

I also took melatonin before going to sleep Sunday night. However, I woke up about 3:30 AM. I gave myself 15 minutes to fall back to sleep naturally. When that didn’t work, I popped an Actifed. I think I was back to sleep by around 4:30 AM. This was the only time I had trouble sleeping at the right time.

I woke up a little late and a little tired Monday morning. My chosen drug to help me wake up is simple caffeine, and so I had two cups of hot black tea upon rising. I made it to work about 10 AM feeling mostly natural.

Tool #4: Fasting. Avoid eating any food while in transit, and then eat at the correct time in your new time zone.

This was the idea that inspired me to take a no-holds-barred approach to hacking jet lag in the first place. I did not eat a single thing in transit. That amounted to about 20 hours of no food. My first meal back home was a late lunch upon arriving in Los Angeles. From then on, I simply ate normally and at normal times.

As I understand it, this is the core of the lesson from the study done by the Harvard Medical School. The idea is that this period of fasting, followed by eating at the “correct” time, is a trigger that signals your body to reset its internal clock to the new time zone. The study suggests that fasting 16 hours is enough to activate the trigger.


This was not a scientific experiment. There was no “control”, nor can I tell you how much one tool paid off versus the other tools.

What I can tell you is that I made an 8-hour time shift in the more difficult direction and was free of jet lag within about 44 hours. I touched down Saturday afternoon and was able to hit work Monday morning feeling back to normal. I accomplished this with just the four simple tools described above (and lots of love, encouragement, and support from my understanding wife).

The overall approach may sound misery inducing, but I never felt miserable. Most of the time I actually felt fine.

For one thing, I’ve never enjoyed airplane food, so fasting was not a hardship. I’ve also never been entirely comfortable sleeping in-flight, so most of the sleep deprivation wasn’t an issue for me either. As for the drugs and the sunlight/sunset, those are just no-brainers as far as I’m concerned. The hardest part was staying awake Saturday until my correct bedtime the first night back home – but even that was not too bad (my wife helped by standing guard).

But if you’re not interested (or not able) to use all four of these tools, it’s possible that the ones you are willing to use can make a significant improvement for you the next time you have to adjust to a new time zone. And of course, there’s a wealth of additional research and advice available online for dealing with jet lag – the wikipedia entry is a fine start.

I hope this might help you hack jet lag sometime!