Scientists are studying causes and cures for the peculiar jet age malady known as "jet fatigue", according to a recent article in Travel and Leisure. Our bodies are programmed for rhythmic changes during each 24-hour period called the "circadian cycle," generating more energy during busy daytime hours, less at night, and so on. But when we hop a jet and fly east or west through six time zones, the system is thrown out of whack. Energy signals are issued at the wrong times, and we may spend the first days of that dream vacation feeling tired and dragged out.

The article suggests these steps to help combat jet fatigue: 1) Start adjusting to your new time schedule a few days before beginning your trip. 2) Get as much sleep as possible en route to your destination. 3) Break long trips with stopovers. 4) Upon arrival, take it easy, but try to adjust to local time schedules.

Q. Underline the short expression which supports the conclusion arrived at in question No. 1.