After crossing an ocean and a couple of time zones, it's likely you'd welcome a lengthy power nap over embarking on any kind of ambitious sight-seeing tour or serious meeting with your customers and suppliers.

As it turns out, the dreaded jet lag, as it's called, happens when you travel through multiple time zones, confusing your body's 24-hour inner clock and throwing off your "circadian rhythms." These rhythms control the release of hormones, which tell us when we're tired or hungry. Signs of jet lag include fatigue, insomnia, headaches and disorientation. For each time zone you travel, it typically takes a day to adjust back to the normal cycle of night and day. Travelers typically experience more acute jet lag when traveling through multiple time zones and when traveling east, as opposed to west.

While the temptation is to combat jet lag by settling down for a major sleep once you arrive, it's often a better strategy to force your internal clock to make the adjustments immediately—meaning you should stay awake until it's the local time to sleep. And even altering your daily schedule slightly before hitting the road can help you adjust.

Here are some suggestions for easing the effects of jet lag and ensuring you don't lose out on any productivity or time for fun.

Reset your clock. This is something you should do both for your internal clock and your wristwatch. If you're taking a big trip across many time zones—flying to Asia, for example—start helping your body clock adjust by altering the time you go to bed and wake up slightly over the course of a week or so prior to your departure. Also be sure to reset your watch to the proper time of your destination as soon as you board the plane so you begin to make the mental adjustment immediately.

Stay hydrated. Drink plenty of water during the flight to stay hydrated. No matter how tempting it might be and how much time you have to kill, try to refrain from coffee and alcohol, this will only dehydrate you even more.

Keep active. Be sure to walk around as much as possible on the flight or do stretching exercises to keep your blood circulating. When you arrive, resist the urge to hunker down and get to bed and instead spend some time outside in the daylight—both the exercise and sunlight can help reset those circadian rhythms.

Watch what you eat. Meals that are heavy in carbohydrates will promote sleep, while those that are protein rich will help keep you awake. Be sure to choose accordingly. What you eat the day or so before you travel can also help. Be sure to eat three balanced meals the day before you travel consisting of plenty of fruits and green vegetables.

Use travel aids. Bring an eye mask and ear plugs along for the ride to help you get sleep on the plane. Talk to your doctor about medications that can help you sleep during the flight, though make sure you have enough time on the plane to sleep off the prescribed dosage. Also note that some medications can cause disorientation and drowsiness the next day, so they'll only exacerbate any jet lag symptoms.