How to prevent travel upsets.

If you're planning a vacation or important business trip, the last thing you want is to wind up suffering from an upset stomach or jet lag. According to two specialists at the University of Oklahoma Health Sciences Center, "staying on schedule" is the key to hassle-free long-distance travel, whether by plane, train, or automobile.

Constipation is the main stomach problem travelers encounter, points out Robert A. Rankin, associate professor of medicine and a digestive diseases specialist. "Constipation is not related to what you eat, but to your bathroom habits. If you get up every morning at 7 a.m. and go to the bathroom, your body's going to be used to that. If you change that routine to another time, you may suffer constipation. Or if you're traveling in the car and need to go to the bathroom, but there isn't one for 25 miles, you just suppress it. And you get constipated. You're more apt to get constipated as you get out of your daily routine."

Crossing time zones and trying to adjust biorhythms to the new time also can be difficult, notes O.H. Rundell, adjunct assistant professor of psychiatry and behavioral sciences. "Eastbound travel is much more disruptive of one's sleep and much more disruptive of one's biological rhythms than is westbound travel. When you go east, you're moving forward in time and against the biological rhythm. If you go two time zones east, you would be going to bed two hours earlier and getting up two hours earlier. That's hard to do."

To reduce travel bugaboos:

* Stay on your regular schedule when eating.

* To prevent heartburn, restrict intake of rich foods and drink. If...