Riding in the car for long periods of time can cause your joints to become sore and stiff from the lack of activity. Asta O'Donell, an exercise therapist in Washington, DC, who works with people with chronic conditions, suggests that you stop to get out of the car and stretch about every hour and a half along the way--or more often if your body becomes stiff quickly.

Following are some exercises O'Donell recommends doing on your trip.

• Raise and lower your shoulders a few times, then rotate your shoulders forward and backward.
• Sit up or stand up as straight as you can, pulling in your stomach muscles, lifting your rib cage and keeping your shoulders down.
• Maintain good posture by adjusting your rearview mirror so you have to sit up very straight to use it.
• Tilt your head gently to the left, then to the right. Then turn your head very slowly to either side.
• Flex and rotate your ankles a few times.
• Stretch your arms in front of you, then to the side and toward your back, squeezing your shoulder blades together.
• Make fists with both hands, hold for a few seconds, then release. Make a clawing motion by curling your fingers and releasing. Then open your hands and stretch your fingers as wide as you can.