How to beat jet lag: Why is jet lag worse when flying east?

West if best, east is a beast. Heard that one before? It's the rhyme of the jet-lagged traveller. It is well known that travelling east, your body takes longer to adjust than travelling west and science has some fresh ideas that explain this phenomenon.

In an article in the journal, Chaos, researchers concluded that for most of us, our circadian rhythms – the internal sleep-wake clock that tells us when to sleep and when to get up – are slightly longer than 24 hours. Therefore travelling west, and coping with a later sleep-wake time than at home, comes more naturally than travelling east, and hitting the sack earlier. So for Aussie travellers on holiday in Europe, the jet lag is likely to be worse when they get home than it is in Europe.

If our bodies are working on a longer-than-24-hour clock, how is it that we are not wildly out of sync with the day? The reason is that there are a couple of external cues that help our body clock adjust, and the big one is light. The bright light of day resets our circadian clock and tells us to get out and start hunting and harvesting, or sightseeing; darkness tells us it's time for bed, and this is the reason that science says the blue light of a tablet device at bedtime could contribute to poor sleep.

Why is it then that waking up in your gasthaus to a bright Bavarian morning on day one of your trip does not reset your body clock immediately and say auf wiedersehen to jet lag? According to researchers at Oxford University, the reason is the protein, SIK1, which inhibits the impact of light on the brain. Bright light acts as a stimulant but then along comes SIK1 and quietens things down again, limiting our ability to adjust quickly when we cross time zones. When the researchers experimented with mice, halving their levels of SIK1, they found that the mice could adapt to a six-hour change in the daytime-night-time cycle in just one day, versus six days for the control group. No doubt SIK1 is vitally important for the functioning of our organism but evolution just wasn't thinking about jet lag when it was designing mammalian architecture. Any scientist who finds a way to safely block SIK1 for humans is on the road to riches, and you can bet there are clever minds working on the problem now.

Armed with this knowledge, science says we can still strategically use light to regulate our body clocks and get over the effects of jet lag more quickly. Let's say you've travelled from east coast Australia to Italy, covering eight time zones, assuming this is the northern summer. Travelling west, you want to delay your body clock. If you normally hit the sack at 10.30pm, that equates to 2.30pm in Rome. That needs sorting, and exposure to bright light will help you push back your bedtime, and here there are two theories.

According to Steven W. Lockley, a consultant to NASA's fatigue management team, trying to fit in with your new time zone right away is wrong since it leads to exhaustion. "What you need to do is to ease yourself into the new time zone by consciously manipulating your exposure to light." Lockley advocates a gradual shifting of sleep-wake patterns until you're in sync with wherever you happen to be, and using light to assist. Travelling west from Australia to Rome, you want to push back your sleep times and therefore you would avoid bright light when you wake and ramp up your exposure later on in the day, gradually cranking your bright-light time closer to your wake-up time each day. There's even an iPhone app to help you work out these gradual changes in your light-exposure schedule, Entrain, developed by researchers at the University of Michigan.

Another jet lag study published in the Cleveland Clinic Journal of Medicine supports this softly-softly approach, and posits that most travellers can push their body clock back by two hours a day, which suggests it would take four days to get over jet lag and adjust to normal waking and sleeping hours in Italy. This implies that on day one of your Italian journey you would be in the sack at your Australian bed time plus two hours, say 4.30pm Italian time, and would spring awake eight hours later, at 12.30 am.

Really? Beddy-byes in mid-afternoon, awake for a new day just after midnight? In summer in Italy? What the scientists are not taking into account is the stimulating effect of being in a foreign country, and that's worth several hours of adjustment at least. In bed when the Italians are heading to the piazza for an Aperol spritz? Not on my watch.

For what it's worth, my strategy for overcoming jet lag is more "When in Rome…". Get in the local groove from the get-go and eat and sleep according to the time zone you're in.