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On the Spot: What's the culprit in jet lag?

Could airplane cabin pressurization be the culprit behind a bad case of jet lag?

February 26, 2012|By Catharine Hamm, Los Angeles Times

Question: In January, my husband and I flew to Rio de Janeiro from LAX, as we have done many times. But this time, something unusual happened. We had never had jet lag like this before, and we had it at both ends of the trip. If it had been just one of us, I might have thought one of us was coming down with something. The fact that it happened to both of us, both ways, same symptoms, makes me wonder whether they might be pressurizing the plane differently. Is it possible that caused our jet lag?

Monica Hobin

Santa Barbara

Answer: As I write this, it's 9:26 a.m. in Los Angeles and 3:26 p.m. in Rio. Writing in the New England Journal of Medicine, Dr. Robert L. Sack said about 30 million people suffer from jet lag, which kicks in after five time zones are crossed and your body clock gets confused about what time it is. Jet lag has a variety of symptoms, including insomnia, digestive upset and cognitive impairment, he noted. That means there are about 30 million zombies out there with bad stomachs at any given time, which may explain America's recent fascination with the undead. Something has to.

Why some people suffer horribly from jet lag and others do not (I, thankfully, fall in that latter category) is not really known, said Dr. Charles D. Ericsson, head of travel medicine and a professor of medicine at the University of Texas Medical School at Houston. It could be genetics (thanks, Mom!). But Ericsson added that as we age, we don't tolerate time changes as well.

That's not all, said Dr. Ryan S. Hays, assistant professor of neurology and neurotherapeutics at the University of Texas Southwestern Medical Center in Dallas. "Other factors that can worsen the symptoms include the direction of travel (east versus west), the time of departure [or] arrival and how well-rested the person is prior to travel," he said in an email.

But could pressurization be the culprit or even a culprit? That's not known with certainty. What is clear is that flying can make you feel lousy.

"Typical cabin pressures mimic an elevation of around 8,000 feet above sea level," Dr. Tanvir Hussain, a Los Angeles cardiologist, wrote in an email. "At sea level, a typical person's blood oxygen saturation (a measure of the amount of oxygen being carried by red blood cells) may be around 98%." At 8,000 feet, "a healthy person's blood oxygen saturation will drop to around 90% or so." That can cause mild hypoxia and alkalosis, "a mild acid-based imbalance in the blood," he said. "It's a combination of mild hypoxia and alkalosis that is thought to cause the soft symptoms of jet lag, e.g., nausea, headache, fatigue, essentially a mild form of altitude sickness."

So what happened to Hobin could be any one of these things, all of them or … none of them, and it could be a blip on the body's radar. As for addressing jet lag, all time-zone-crossing travelers have their own solutions: the feasting/fasting diet before a trip (I've used one from Argonne National Laboratory that can be found at; resetting your schedule before you go so that your activities here match the activities there; acupuncture; and prescription sleeping medication.

If you still feel like a zombie, rent any movie with "of the Living Dead" in the title. Any one of those could put you to sleep.

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