For thousands of years, people didn't experience disruption in their sense of time and place because there were no rapid means of transportation. They could only go as fast as their feet could take them, their animals could carry them, or their boats could transport them. It took weeks, months, years, or even generations to travel great distances.The invention of the airplane changed all this. However,although we can travel by place now, our bodies have not yet adapted to long-distance air travel. That is way we suffer the consequences-jet lag.