It’s a common term, but what do we really mean by jet lag?
I would say jet lag is a kind of circadian misalignment that happens when:
1. your body is aligned to your environment, meaning you’re sleeping at night and active when the sun is up, then …
2. you quickly travel to a place where the sun rises and sets hours later or earlier.
From the point of view of your body’s clock(s), this is pretty similar to the situation faced by shift workers who work, say, 7 pm til 7 am, but also want to spend time with their family, who want to be up and active from 7 am to 7 pm: it’s like they live in New York City but travel to Beijing for work. Hopefully the commute is shorter, at least.
Earlier this summer, I traveled with my wife to the Netherlands, where she gave an invited talk at a conference in Eindhoven. I was excited to get a chance to test out the science behind Arcascope’s tech firsthand! For reference, we were hoping to be waking up 7 hours earlier than we normally do.
If we made no adjustments beforehand, we’d land in Amsterdam aligned to the central US. Boom, jet lag. To avoid that, we started preparing ahead of time. Basically, we wanted to suggest to our brains that the sun had a schedule similar to that of north-western Europe. In the Netherlands, the sun has been setting nearly at 10 pm, which is 3 pm in the central US. Conveniently, that’s also around the time I’d expect our circadian clocks to enter their delay region, the hours when light causes our internal clocks to slow down, which causes us to lag behind our environment’s natural sense of time. This delaying effect is usually counteracted by the advance region in the morning that makes our clocks run faster than our environment. But, if we “skipped” the delays, then advancing in the morning would add up to waking hours earlier than before. (Our CEO, Olivia, has written about this strategy before.) Here’s what our app Arcashift would tell me to do on day one.
To this end, we would put on dark sunglasses after about 4 pm. Dark enough that it was like being in very dim lighting, but not totally black. We could feel ourselves getting super tired hours much earlier! I was surprised by how dramatically tired I’d get; I expected to feel sleepy somewhat earlier as our clocks moved, but perhaps the experience was amplified by our melatonin not being delayed by evening light. In any case, we were waking up earlier than usual in a day or 2, naturally around 4:45-5:00. Once awake, we were getting the brightest indoor lights we could until early afternoon to get as big of a push as possible from our advance regions– the brighter the light, the bigger the effect of advance or delay.
Here’s what my “day 2” of adjustment looks like on Arcashift; our sleep wasn’t adjusting that fast, but we also weren’t following the advice that closely, since we got light for a few hours in the afternoon instead of dimming for good at lunch.
The effectiveness of this strategy was incredible! We landed in Amsterdam early (local time) on a Saturday, met up with some friends and traveled to Eindhoven. Yeah, we were groggy that day, but we’d also kind-of-slept for about 3 hours on a plane. Settling into our room that night, it felt like 8:30 pm, and our bodies were winding down. The following morning, my eyes opened around 6:30 am, nearly my normal wake time in the US, having slept through without the 3 am wide-awake I was expecting. No sudden drowsiness around 11 in the morning, as I’ve had before when traveling to Europe. It was as though we’d been there for a week; no jet lag at all, even on subsequent days.
Self-awareness time: we had our first child last summer, so it’s possible our threshold for “I feel rested enough to function” is extraordinarily low right now. But I got some of the best sleep I’ve had since, with our little one safe and happy across the Atlantic with grandparents, and it’s hard to argue with unbroken sleep blocks as a sign that sleep drive and circadian rhythm are in sync.
A few days before we returned, we again started using sunglasses to adjust ourselves. This time, we wanted to delay as much as possible; hence we wore sunglasses in the morning and then got as much light as we could in the afternoon and evenings. Here’s what Arcashift would tell me if I were trying to adjust my wake time 7 hours later, the shift we were trying to do to come back. How did it go? To be honest, not as well as the other direction. This could be for a few reasons, such as we wanted to explore Amsterdam in the mornings, and it’s very bright outdoors even with sunglasses on. So, we probably didn’t block as much advance region as we could’ve had we stayed indoors. We’re also big morning larks, so staying up late and waking up late is not something we enjoy, which also lowers the amount of adjustment we really took advantage of– had we gotten light until 3 in the morning, as Arcashift recommends, it would have really amplified our delaying.
Arcashift dynamically finds the patterns in your activity data, so knew that we weren’t staying up late and getting all of that boost, so when we got back and felt jet lagged, Arcashift could see we still needed to do quite a bit of adjustment.
Arcashift also gives the user control over the intensity of the adjustment. We didn’t like staying up late, so wanted a more gentle schedule that didn’t ask as much of us. Here are the first 2 days of Arcashift’s recommended schedule if we were to start moving on the day I’m writing this (October 5th), but with a Gentle intensity. Checking out our alignment score, by Sunday, October 8th, we’re nearly aligned on the gentle schedule; that’s a day later than the Moderate schedule that has us staying up until 3 am tonight.
I know my job exists because the science underpinning our tech is true, but to get such a big effect advancing to Europe from such a simple intervention as sunglasses took me by surprise, making me a “true believer.”