We all know what it’s like: you’ve scheduled a number of important meetings to make the most of your business trip, then, thanks to the time difference between your destination and your home town, you’re half asleep and struggling to focus through most of them.Jet lag can be a business traveller’s worst enemy, making you feel tired, run down and often physically unwell at exactly the time when you need to be at your best. The reason for this dreaded condition is the disruption we experience to our circadian rhythm when we travel through two or more time zones.What Is the Circadian Rhythm?The circadian rhythm is what most of us know as our ‘body clock’. It reacts to light and dark to tell our body when to sleep and when to be awake. Unfortunately, while human beings have found a way to travel quickly through time zones, our bodies have yet to catch up and it can take several days for our circadian rhythm to adjust.Why does this matter? Because sleep is an important factor in performing to our best - mentally and physically. Losing just an hour and a half of sleep can lessen our daytime alertness by a third, having a detrimental impact on our memory and thought processes.So, now we know how important it is, what exactly can we do about it?Before You GoPreparing for a business trip can be a stressful time, but try to get everything ready well in advance to make sure that stress before the flight is kept to a minimum. The best preparation for a long-haul flight is a good night’s sleep the night before and, if you can fit it in, an exercise session before you set off. This way your body will be relaxed and ready to sleep when you need it to.On the FlightOne of the most important things you can do to help your body adjust while you’re actually on the flight is to stay healthy. That means: eating well and drinking plenty of water. Try to avoid alcohol and caffeine, which can both affect sleep patterns and the quality of sleep you will be getting.It’s a good idea to try to move around a bit during a long-haul flight, so get up and wash your face and brush your teeth to prepare your body for sleep if you’re travelling through the night. It will not only help with circulation but will ready your mind for sleep.Comfort is important in being able to sleep, or even just relax, inflight. Use pillows and blankets to help you get comfortable, take off your shoes and wear loose fitting clothes.Most sleep scientists agree that light is the key factor in adjusting to a new time zone and you can start to prepare your body for this on the flight. If you are flying at a time that will be night in your new destination, try to limit the amount of light you see during your flight by wearing sunglasses. If, however, you’re flying in the dark but at a time that will be daylight where you’re going, keep the lights on.When You ArriveAgain, light will play a major factor in helping your body adjust, so if you’ve flown into daylight make sure you get outside. Try to soak up as much light as you can to help your body clock work out what’s going on.If you arrive at night, keep lights dim. Try to avoid TV and computer screens, as the bright light they give off will only confuse matters. Tip: apps like Flux and Dimmer will help avoid this problem.With business drinks and meals it can be difficult to eat well on a business trip, but limiting alcohol, avoiding caffeine and trying not to eat overly rich foods will all help with promoting a good night’s sleep.At Work in a New Time ZoneBe kind to yourself - if possible, try to arrange meetings for a time of day that would have been part of your working day at home. For example, if you’re five hours ahead, try to book in meetings in the morning or midday and avoid the afternoon, which would be late night back home.Try to let as much light (preferably daylight) into the meeting room as possible. This will queue your body to be awake and alert.The thing to remember about travelling across time zones is that it will have an impact on your performance. Give yourself the best possible start by taking some of the advice above and you’ll be sharp and focused for everything you want to achieve.