We should have fixed jet lag by now

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In September 1970, a story with disturbing implications for business travellers appeared on page 36 of the Financial Times.

It was about what the newspaper called “the so-called jet lag”, and it revealed that an experiment on 14 volunteers who had flown from London to San Francisco and back had produced unhappy results.

Scientists who collected reams of measurements from the guinea pigs, and 50 gallons of their urine, concluded the flyers’ performance had been “significantly upset” by the trip for as long as five days. The travellers took up to 20 per cent longer to reach a decision, raising fears they might have appeared feeble at the negotiating table. Worse, there seemed to be no cure in sight.

I found this story last week when a haze of jet lag from a 23-hour flight to London from Australia made me wonder how long researchers had been studying the tedious scourge, and whether they were any closer to a decent solution.

The answers are not quite what I expected. As the 1970 Financial Times story shows, scientists have spent more than 50 years studying what happens to the human body when it is shunted across multiple time zones at speed.

In that time, big strides have been made in understanding the root cause of jet lag — a body clock thrown out of whack — and what should help to tackle it. 

The most promising solutions concern light, a key regulator of the circadian rhythms that make us alert or drowsy over the course of roughly 24 hours.

Left to its own devices, the body takes about a day for every one hour timezone crossed to adjust to a long flight, meaning it takes more than a week to recover from a trip like mine from Australia.

But researchers now know the system resets faster when exposed to light at the right times before, during and after flights. Their findings have been used to develop a raft of smartphone apps and online calculators that help flyers figure out the best times to get a dose of light or darkness — in theory.

In practice, almost no one uses these things. Just one out of 460 passengers on Australia’s Qantas airline used a jet lag app, a 2020 study found, and only half went outdoors to adapt to their new timezone. Even savvy international business travellers seek out help for jet lag from the internet, colleagues, family and friends, not calculators, another study showed.

“It’s been hard to put into practice what we know from circadian biology,” one author of both studies, the University of Sydney’s Dr Yu Sun Bin, told me last week.

I have an idea what the problem is, having tried a couple of jet lag calculators. You need a will of steel to follow their sometimes complex advice to spend, say, three hours in the dark after 4.30pm on your first day in Sydney, or remember to be in light at midnight three days later.

Stanford University scientist Jamie Zeitzer showed eight years ago that being exposed to short bursts of light while sleeping did a better job of resetting body clocks than continuous light.

His research has been used to develop an app-controlled sleep mask with LED lights that is supposed to help curb jet lag. But there’s a catch: its $298 price tag.

I can’t imagine making an investment that size, so I was relieved to hear what Zeitzer said when I asked how he dealt with long-haul flights.

“I am not opposed to sedating myself,” he said. Sleeping pills might not be perfect, he added, but they do help conquer the exhaustion that intensifies jet lag for those of us lacking the ultimate aid: a seat in business.

Zeitzer also advises care with coffee while travelling. A cup that has little effect at home can play havoc on the road, when unfamiliar surroundings make it hard to sleep. But his key recommendation for avoiding jet lag again comes back to light — find a reputable app that can show you when to get and avoid it.

I suspect a more systematic approach is needed. The importance of getting the right dose of light or dark should be more widely understood. Airlines could provide jet lag guidance whenever a ticket is booked. Employers could offer travelling staff similar advice. Ultimately, we have more knowledge than ever about how to tackle this problem. It seems a shame not to make better use of it.