There's been a lot of talk lately about personal health when it comes to long-haul air trips, the best precautions being the same as they are on the ground. In short, passengers should understand the effects of flying at high altitudes.

Most at risk for flight-related illness are those who have health problems on the ground. These are the same people who should take precautionary measures when they board a plane that will take them 30, 000 feet above sea level. Commercial jet aircrafts have to maintain a relative cabin altitude between 5, 000 and 8, 000 feet during routine flight.

What that means is oxygen content is lowered and the air extracted from the outside environment at high altitude to be mixed with recycled air tends to be extremely dry, causing the inside cabin humidity to remain low, ranging anywhere from 10 to 20 percent, causing medical conditions, most notably those involving the respiratory system and skin.

Airlines are conscious of passenger needs and comfort. A common practice is that flight attendants are trained to make sure passengers have enough water throughout the flight to prevent dehydration.

Although these unique factors of long-distance flying do not pose a health or safety threat to most, there are guide-lines you can follow that will improve your comfort level during and after a flight. Most important is that passengers should perform isometric leg exercise and simple arm movements, especially during long flights. We recommend you do these exercises three or four times every hour. None of them should be performed if they cause pain.

We recommend that passengers prepare for a flight long before it takes place. It's also important to avoid pre-flight stress. One should obtain an adequate amount of sleep before beginning a trip.

Tips for the Traveler

• To reduce stress, allow extra time for check-in and connections
• Drink eight ounces of water per hour in flight
• Drink any caffeinated or alcoholic beverages in moderation
• Perform in-flight exercises, and walk around the cabin if possible
• Eat lightly
• Consult your doctor before flying if you suffer from any chronic ailment
• Consult your doctor if you suffer from motion sickness

Ankle Circles:
Lift feet off the floor. Draw a circle with the toes, simultaneously moving one foot clockwise and the other foot counter-clockwise. Reverse circles. Do each direction for 15 seconds.

Forward flex:
With both feet on the floor and stomach held in, slowly bend forward and walk your hands down the front of your legs toward your ankles. Hold stretch for 15 seconds and slowly sit back.

Knee To Chest:
Bend forward slightly. Clasp hands around the left knee and hug it to your chest. Hold stretch for 15 seconds. Keeping hands around the knee slowly let it down. Alternate legs. Repeat 10 times.

Arm Curl:
Start with arms held at a 90-degree angle: elbows down, hand out in front. Raise hands up to chest and back down, alternating hands. Do this exercise in 30-second interval.

Knee Lift:
Lift one leg with knee bent while contracting your thigh muscle. Alternate legs. Repeat 20-30 times for each leg.

Neck Roll:
With shoulders relaxed, drop ear to shoulder and gently roll neck forward and back, holding each position about five seconds. Repeat five times.

Shoulder Roll:
Hunch shoulders forward, then upward then backward, then downward, using a gentle circular motion.