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3 Ways to Combat Dehydration
and Fatigue in Flight

By MS. RUTH ANN REPLOGLE, Staff Writer

When we think about humidity, we usually associate it with dehydration due to high temperatures, but high altitudes and low humidity can dehydrate you, too.

Cabin-relative humidity is approximately one-third of one percent and the outside maximum absolute humidity of this atmosphere is a fraction of that.

Low ambient humidity can cause your body to dry out and become dehydrated. Dehydration in-flight particularly affects your respiratory tract, which includes your nose, throat, and lungs, as well as your eyes. This can lead to weariness, muscle cramps, and fatigue, all of which affect task performance in the air.

So what can you do about it?

1STAY HYDRATED. The longer the flight, the increased loss of bodily water. Men can lose up to 2 liters of water and women up to 1.5 liters of water during a 10-hour flight—that is nearly 4 percent of your body’s water weight! You can replenish with fluids or fluid-like foods. Drinking water (with or without electrolytes) is your best bet. Sip, do not chug, 8 to 10 ounces of water for every hour you are in the air. You also can eat your water by consuming a banana, pickles, dates, or a packet of tuna.

2AVOID CAFFEINE. Caffeine (e.g., coffee or tea) can actually do the opposite of keeping you alert. While it may temporarily give you an energy boost, the buildup of caffeine in your blood stream can mess with your heart rate and cause you to be tired. Also, caffeine is a diuretic, which means you are more likely to lose the essential electrolytes that keep your body hydrated through more frequent urination.

3MOVE AROUND AND STRETCH. Aerobic exercises—such as static stretching or yoga—increase blood flow and relieve muscle tension. Here are a few static stretches to try:

  • Shoulder Stretch: Relax your shoulders, bring one arm across your body, and hold it with the other arm just above the elbow, pulling gently toward your body.
  • Chest Stretch: Clasp your hands together behind your back. Gently straighten your elbows and raise your arms as high as possible.
  • Quadriceps Stretch: Standing, hold onto a chair or press against a wall with one hand. With your other hand, clasp your ankle and pull your heel into your butt. Switch sides.
  • Hip Flexor Stretch: Kneel on your right knee, with your left foot in front of your body. Lean forward from the hips. Switch sides.
  • Overhead Stretch: Interlock your fingers and reach above your head.

If you are one of the crew members whose duties require you to stay seated, there are aerobic exercises you can do sitting down:

  • Arch back while stretching arms upward. Reverse arch and slump forward.
  • Rotate head and neck.
  • Extend both arms level from shoulder to side and rotate shoulders.
  • Rotate arms from elbows.
  • Extend each knee so your leg is straight, contracting thigh muscles.
  • Move toes up and down, then side to side.
  • Rotate ankles.

Following these three steps will help keep your mind sharp and your body strong whether you are on short-range or long-range flights.