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By James D Lakin
Minnesota Flyer 

Jet lag: Is this Brussels or Bangkok?

Aeromedical Forum


PhD, MD, FACP CFI, CFII, MEI FAA Senior Aviation Medical Examiner

An alarm clock is something I rarely need. That good ol’ internal ticker goes off just about sunrise.

Likewise, I need a good reason to stay up long after it gets dark. “Sorry Honey. It’s my bedtime.” In other words, I have a strong circadian rhythm. That puts me in the company of most living creatures. Plants, animals, even single-cell organisms follow a relentless daily activity pattern linked to the light-dark cycle.

Why this sleep/wake pattern is so strongly imprinted on almost all living things is a mystery. Some biologists have suggested that circadian rhythm originated at a very early stage of evolution to protect the DNA of single-cell life forms from high ultraviolet radiation during the daytime. It’s when we are sleeping that cell division and growth spurts are at their peak.

Indeed, when our little grand-daughter has a sleep-over, I think she grows an inch a night. Circadian rhythms are not only important for regulating sleep patterns but they also regulate brain wave patterns, cell regeneration, hormone production and a score of other biological activities.

You might call it the body’s preventative maintenance cycle. As you get older, normal circadian rhythms gradually change. You get sleepy earlier. You wake up earlier. The need for daytime napping increases. That’s why our grand-daughter and I get together for another growth spurt in the afternoon. It’s no surprise that if something so primal in our internal wiring is disrupted, it can mean trouble. For example, the first day after flying to Europe, I might just as well be on Mars for all that I notice. That’s not a big deal if I’m merely a tourist asking the way to the Champs Élysées. If however, I were to be expected on the flight line in 24 to 48 hours, it would be a problem. Indeed, I would be suffering from “Circadian Rhythm Disruption” or CRD. As pilots are flying faster and more capable aircraft, they become increasingly susceptible to CRD, crossing more and more time zones. An airman suffering from CRD may experience

• Oversleeping and difficulty getting up

• Negative moods

• Trouble falling asleep and staying asleep

• Late-night insomnia

• Daytime sleepiness

• Lack of energy in the morning

• Increased energy at night

• Difficulty maintaining alertness, focus, concentration

Put that all together and you can expect a slowed reaction time, decreased attention span and impaired memory in the cockpit. You could easily fly over KMSP even without being distracted by your laptop!

The FAR’s recognize the importance of rest periods for flight crews. Admittedly Part 91, governing general aviation operations does not mandate any specific rest requirements. Common sense coupled with §91.3 – “The pilot in command …is directly responsible for, and is the final authority as to, the op eration of that aircraft” — strongly suggest getting a good night’s sleep. Commuter and On Demand Operations (§135.261-135.273) as well as Flag and Domestic Operations (§121.467-121.525) are regulated by obligatory rest and duty periods. However, until the last year none of these regulations took into account the effects of time zone transition and CRD. Fortunately 14 CFR Part 117 now provides detailed instruction on permissible flight duty and required rest periods for travel that, among other things, exceeds 60 degrees of longitude. If you bust through more than four time zones, a flight crew member must be in the new location for 72 hours or be given at least 36 consecutive hours free from duty before being considered “acclimated”(§117.3) --- in other words knowing up from down! These regulations apply to Part 121 operations. Although on-demand operators as well as GA pilots would do well to read them over.

So what’s a jet-jockey to do when he suddenly finds himself half-way round the world? Obviously you should get a good night’s sleep before the flight The best way to manage jet lag if you are going to be in the new location for a while is to assume the wake-sleep pattern of the destination site immediately.

If however, you’re doing a quick turn-around, the FAA recommends trying to stay on your original time zone. Make sure your hotel room has good shades on the windows. You might even consider a sleeping mask and ear plugs if the hotel the airline booked for you is next to the Moulin Rouge.

They can have some pretty noisy street fights about 4:00 a.m.! Using 3 mg of melatonin about three hours before you go to sleep may help. After waking up, caffeine can be useful. I’d highly recommend a double espresso with almond flavored biscotti. If you are not at the controls, strategic napping may be useful. If you still feel dog-tired in spite of all these smart ideas, it would be better to reschedule the flight. The good old U.S. of A. will still be there when you finally arrive!

Fly wisely. See you next month!

As always, comments, questions and suggestions are welcome: jdlakin@mnallergyclinic.com.


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