Flight Training - February 2015 - 50

INSTRUCTOR REPORT»

CAREER PILOT

Flight physiology

Humans weren't meant to fly, and here's why
» By Pete Bedell

IN THE DECEMBER 2014 issue, I
discussed a marathon flying day
I had many years ago ("Advanced
Pilot: Fit to Fly?"). I was in my late
twenties then, and I quickly learned
why spending half a day at altitudes
from 8,000 to 11,000 feet really can
take a toll on those of us who live at
lower elevations.
In the late 1990s, as a reviewer
of products for AOPA Pilot, I
got a chance to play with a pulse
oximeter and used it on several
flights. The results were eye opening. I always attributed headaches
following long flights to my

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David Clark headset-affectionately known otherwise as "David
Clamps." I should've given my
old DCs some slack. After cruising home from Wichita at 11,500
feet, a check of the pulse oximeter
showed my oxygen saturation level
(SpO2) at about 88 percent and my
pulse was pushing 100 beats per
minute (bpm). At sea level, I registered 99 percent SpO2 and pulse
of 60 bpm. No wonder I felt so beat
after long flights!
I almost always climb high for
long flights since that's where
light airplanes achieve their best

true airspeed on minimal fuel. But
what the pulse oximeter so vividly
told me was that I was starving my
brain of oxygen while my heart
was working overtime to keep it
satisfied. I descended to 9,500 feet
where SpO2 was 92 percent but
my heart was still beating fast.
I began to bring an oxygen bottle
and learned the positive effects that
using it had even at the so-called
"breathable" altitudes, where the
regulations don't require supplemental oxygen. After strapping on
the oxygen at 11,000 feet, SpO2
returned almost instantly to 98 percent and, over time, my heartbeat
settled down to a much more reasonable 70 bpm. Most important,
when I landed after a long flight at
altitude, I didn't feel like I'd been
run over by a truck anymore.
Later, when I started flying long
flights for a major airline, I noticed
the importance of staying hydrated.
At first, I noticed sinus problems
because of the dry air at altitude.
I also could drink a liter bottle of
water on a four-hour flight and
not have to visit the lavatory. After
a little research, I found that the
cockpit of an airliner has about 3
percent humidity, even less than the
Sahara Desert. Airline cabins are
dry, too, but better (10- to 20-percent humidity) since there are so
many people breathing back there.
With desert-like conditions, I've
learned to combat the effects by
drinking plenty of water. Pilots are
ripe to get kidney stones and word
in the crew lounge is that passing one of these will be a lifelong
reminder that staying hydrated is
a good thing. I use a saline solution
to keep my sinuses hydrated and
apply lotion containing sunscreen
to give my skin something to drink,
while combating the UVB rays of a
less-filtered sun up there.
I like to avoid alcohol within two
nights prior to a trip. While alcohol
is great for getting you to sleep, it
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Flight Training - February 2015

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