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When Jay Olson was invited to give a talk on the psychology of magic at Columbia University in New York, the 25-year-old researcher at Simon Fraser University in Burnaby, B.C., was determined to avoid jet lag on his big day.

So he created a jet-lag prevention app.

Olson was familiar with the body of evidence showing that exposure to bright light is the most powerful way to reset the circadian rhythm, or "body clock."

But when he looked at the existing apps designed to reduce jet lag, he found they were based on dated research, Olson says. "Nobody had come up with a simple, effective and free method of doing this."

Drawing from the best studies he could find, Olson created an algorithm to determine when a traveller should seek or avoid light to prevent jet lag.

His website,, calculates the ideal timing and duration of light exposure based on four factors: the number of time zones travelled, the direction of the flight, and the traveller's usual waking and sleeping hours.

A person travelling from Vancouver to London may normally wake up at 7 a.m. and go to bed at 11 p.m. Olson's calculator suggests that upon arrival in London, the traveller should seek light from 8 a.m. to 12 p.m. (local time) and avoid light from 12 p.m. to 4 p.m. The next day, the person should seek light from 9:30 a.m. to 1:30 p.m. and avoid light from 1:30 p.m. till 5:30 p.m. The cycle should advance by an hour and a half each day until he or she no longer feels jet-lagged, Olson says.

Another option is to begin resetting the body clock ahead of time. Starting a few days before the flight, the London-bound traveller would wake up an hour earlier each day and seek light for four hours after waking, and then follow the recommendations for light exposure after arrival.

To get enough light, Olson recommends going outside or using a portable therapeutic light box. To avoid light, he suggests staying indoors away from sunlight, or wearing dark sunglasses.

According to a 2003 study from George Washington University, light intensity must be at least 2,500 lux to have an effect on circadian rhythms. Indoor light in a room with shaded windows ranges from 100 to 500 lux, whereas outdoor light in bright sunshine is about 20,000 lux.

At 5,000 lux, outdoor light on a cloudy day can still shift circadian rhythms, Olson says, but indoor artificial light is not usually strong enough unless it is a special therapeutic light box or visor, which provide about 10,000 lux.

Olson notes that exercise and melatonin are not as effective as exposure to bright light in shifting the body clock. But timing is everything. Simply trying to adapt to local time can work if a person happens to be exposed to light at the right times. But otherwise, he says, "jet lag can continue for many days longer than necessary."

Olson's Web-based app, now featured in Scientific American's Mind Matters blog, will remain free of charge, he says, since he wants to encourage travellers to avoid the negative consequences of jet lag.

Being out of sync with a new time zone is associated with gastrointestinal problems, fatigue and decreased alertness. If a person is driving in a new country during their peak drowsy period, Olson adds, "it can lead to accidents."

Moreover, a 2006 study from the University of Virginia found that older mice subjected to chronic jet-lag conditions had earlier deaths.

Jet lag is a side interest for Olson, who has applied to research the psychology of magic at the doctoral level. But as a frequent flier, he says he's relieved to have found a way to outsmart jet lag. In the past, he says, "it would ruin the first few days of the trip."

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