Why do i get so tired flying every week?

Every time I fly (which over the last three years has been nearly twice a week), I get tired.  Not debilitatingly tired but enough that I just feel ‘off’ and less productive.  Many people would simply chalk this up to jet lag but the reality over the past three years is that I’ve found that this happens to me even if my flight spans only a single timezone or even within the same timezone.  Also, the rule of thumb that it takes one day to recover for every hour of time difference that you fly seems ridiculous.  If this were the case, it would take me the entire work week to recover from my Monday morning flight across the country (in reality, I’m probably productive by Tuesday) or the entire duration of my trip to Europe to recover.  Evidently this can be true for people with extremely rigid sleep schedules (also not me).  So here’s what I’m chalking my weekly flight fatigue up to…

1.  Dehydration

A study published in the New England Journal of Medicine in 2007 found that air cabins pressurized to 8,000 feet lower oxygen in the blood, making passengers feel uncomfortable and dehydrated (source).  Cabins are also very low in humidity, typically ranging between 10-20%.  This is much lower than a comfortable typical indoor humidity of 30-65% and even the lowest humidity cities in the US average around 30%.  Low humidity increases the risk of catching a respiratory virus, such as a cold since the moisture in the air keeps your airways moist so the lining can help trap germs trying to enter your body.

  • Solution:  Obviously, hydrating but it doesn’t help that drinks in airports cost more than a Qdoba burrito and bubblers (yes, bubblers) are hard to come by.  I didn’t realize this until I had traveled for a while but flight attendants will bring you additional water even if their big beverage show is over.  Don’t be afraid to be “that guy” and order a water AND an orange juice or even ask for additional water after the beverage road show.  It’s probably worth the extra trips to the gross plane bathroom even if you’re in a window seat and the guy next to you thinks you have a growing problem.  I’ve also been told to avoid caffeine and alcohol while flying but I’ve decided that I like coffee and Jack & Gingers too much.

2.  Poor Air Quality

In addition to the low humidity on planes described above, the overall quality of air on planes isn’t ideal.  Surprisingly, this is less a result of recycled air but more likely the cause of being in extreme proximity of already sick people.  Cabin air on planes is completely refreshed 20 times per hour (compared with just 12 times per hour in an office building) (source), only about 50% of the air in the cabin is likely to be recycled, and the oxygen level on aircraft remains pretty constant (source).  Also, most aircraft air is circulated through hospital-grade HEPA filters, which remove 99.97 percent of bacteria, as well as the airborne particles that viruses use for transport (unfortunately, many regional jets lack these filters).  Additionally, cabins are divided into separate ventilation sections about every seven rows of seats (source).  There have been reports of infections (including TB) being transmitted during flights but there is disagreement whether this is due to the the very fine filters not working or simply because the victim is seated close to someone with an infectious disease (source).  This is most likely due to either close proximity to a sick person or a result of the poorer air quality circulated through the cabin at the gate (air circulation is greatly reduced when the engines aren’t on).

  • Solution:  I suppose you could ask to be moved if the person next to you shares that they are ridiculously sick but on a full plane this isn’t realistic.  Otherwise, hope you have an immune system of steel and get a flu shot.

3.  Dozing off while taxiing on the runway

Something about the comfortable (sometimes) seat, the constant subtle vibration, and the ambient white noise always causes me to fall asleep while planes are taxiing.  Evidently, I’m not alone but few discuss this phenomenon in a scientific way.  It does make sense, however, since the brain naturally craves sensory input (people in sensory deprivation tanks hallucinate) and constant white noise, gives the brain a tonic signal that dampens its own internal systems (source).  I suppose the reasons that the low vibrations of taxiing cause me to sleep are also similar.  The problem, however, is that short naps for me are a crapshoot – sometimes refreshing me and sometimes making me more tired.  On a plane, I often don’t reach the 10-15 minutes required for a refreshing “power nap” and as a result just wake up more tired than when I started.

4.  Nutrition

Have you ever tried to eat healthy in an airport?  It will cost you twice as much as shopping at Whole Foods.  As a result, I always eat garbage while traveling and I believe this compounds my fatigue on my travel days.

  • Solution: Pay more for healthier food if you can afford it.  Otherwise, keep eating double cheeseburgers from McDonald’s and enjoy the 10-15 minutes of happiness.

5.  Jet Lag

I just got back from a vacation to Europe where I experienced many of the classic jet lag symptoms (especially insomnia on my second night there due to circadian rhythm disruption).  Although it’s on a much smaller scale, I suppose this does affect my shorter weekly flights.


Trying to fit a normal life in to the three days that I’m actually home on the weekends probably doesn’t help the issue.  Over each weekend, I typically relax my sleep schedule so by Monday morning, even if I weren’t flying, I would likely feel a mini jet lag due to slight changes in my circadian rhythms (aka a case of the Mondays).

Let me know your thoughts and if any of you have any that I should add.

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