The Upside and Downside of Caffeine

by Paul Engstrom, Aviation Writer and IFA Member

Most pilots know what a great pick-me-up coffee can be on days when they're a bit more tired or less alert than usual. But how many know that the caffeine in coffee might let them down after the third cup?

Three or more refills may 'produce deterioration of psychomotor performance and changes in mood which can impair a pilot's efficiency and effectiveness to operate an aircraft,' write Melchor J. Antunano, MD, and Stanley R. Mohler, MD, in the publication 'Human Factors & Aviation Medicine.'

Research confirms that the first two, 6-ounce cups of joe, each containing an average of 100 milligrams of caffeine, do indeed enhance performance. In the cockpit, we feel less drowsy and more able to focus, reaction time is improved, our muscles are energized, we can hear and think better.

It's a different story beyond 300 mg, however. That much caffeine can trigger nervousness, restlessness, mild trembling, gastrointestinal distress and greater sensitivity to touch, pain and other sensory stimuli.

High doses of caffeine also restrict blood flow to the brain. The result: less oxygen to fuel those all-important mental tasks that keep us moving safely through the air. Even just two cups of coffee can reduce the blood flow by 15 to 20 percent, according to David Kerr, MD, who has studied the issue for the British military.

Furthermore, coffee junkies who can't get more brew during a long flight may experience withdrawal symptoms'headache, fatigue, irritability and less vigor and alertness. Who needs any of that when the situation aloft calls for all the acumen a pilot can muster?

There are other considerations, as well:

• First, caffeine is also an ingredient in tea, chocolate, cola beverages and some prescription drugs, such as those for migraine headaches. So, even if you drink only one or two cups of coffee while flying, there may be more caffeine in your body than you realize.
• Second, caffeine doesn't counteract the depressant effects of alcohol. When you push the limits of the '12 hours from bottle to throttle' rule, don't count on coffee to give you an edge.
• Finally, all that java you're drinking could be masking a more serious threat: fatigue.

Maybe what you really need is a good night's sleep'something for which caffeine simply isn't a substitute.

When he isn't flying, Paul Engstrom writes and edits from Sebastopol, Calif. 

The information contained here in is meant for informational purposes only. Neither IFA, nor Paul Engstrom assume any responsibility or liability for events that occur due to actions you or others on your behalf take based on the information given in this article. You are proceeding at your own risk. It is strongly advised that you seek the opinion and advice of a qualified aviation medical examiner and appropriate medical physician for any medical needs you may have.