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ACRO E-mail Archive Thread: [Acro] Cardio and G tolerance- all the replies

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ACRO E-mail Archive Thread: [Acro] Cardio and G tolerance- all the replies


Thread: [Acro] Cardio and G tolerance- all the replies

Message: [Acro] Cardio and G tolerance- all the replies

Follow-Up To: ACRO Email list (for List Members only)

From: "Eric Minnis" <acroeric at>

Date: Tue, 07 May 2002 21:44:49 UTC


I had a ton of request to post some of the replies so here goes. I
removed the names from the replies because it was so hard to cut and
paste but I am sure you can figure out several of them. There is some
excellent information and a good bit of actual experience. Thanks again
to all that replied!
Eric Minnis
N43740 Swick Tcraft
For what it's worth, here's my story. When I started to fly acro I was
an avid bike rider (about 25-30 miles a day). At the time I was flying a
Great Lakes and I found that in the hard pulls (+5) I would start to
gray out, even with a full grunt going. What made me realize that acro
and distance biking was not compatible for me was my instructor having
me fly a hammerhead and pull directly into a loop at the bottom without
grunting. Next thing I remember was my instructor's voice somewhere off
in dream land telling me that he had control of the aircraft and to sit
back and relax. Also keep in mind that "time in G" can be a factor as
well. Whereas 7 or 8 Gs can put you out right now, 3 or 4 Gs for 30
seconds can induce G-loc as well. 
I think military fighter pilots are limited on how much cardio they are
allowed to do as well. I think it's something like 30min three times a
I found that once I moved into the competition box I could no longer
tolerate the bike riding. Once in the box the maneuvers come much faster
than in practice and for me, I found it hard to keep my G tolerance up
under those circumstances.
As my instructor once told me "fat guys can handle more Gs".
I have been flying competition for about 15 years and currently fly an
Extra 300 in advanced.  I have been running for 25 years, marathoned for
a number of years in the late 70's and early 80's, and currently run
about 40 miles a week, bike about 40 miles a week, and do light weight
training 2-3 times a week.  My comments are purely from experience, not
technical or medical.  Clearly, dehydration affects G tolerance.  I pay
close attention in hot weather to hydration, especially when flying.
Overall, the lower blood pressure associated with good aerobic fitness
can reduce G tolerance, but I have not found it to be a big problem.
Work at developing good techniques during flying to maintain blood to
the brain---various gruntings and squeezings.  There is plenty written
about these techniques.  Be careful on your long run days if you plan of
flying.  In the summer here, mornings are better for running and flying,
and I notice more "gray" time if I go straight from a run to a flight.
Positive seems to have more effect than negative, but again it is a
blood pressure and flow issue, so the transitions between positive and
negative will catch you quicker if you are dehydrated, or prior to
hydration after a run.  We all choose how to manage our interests, and
while running does conflict with flying sometimes, I have never felt the
need to drop either.  I am sort of a perenial advanced competitor.  If I
really worked hard and wanted to fly unlimited on a regular basis, I
might need to temper running.  But so far that has not been my goal with
flying so I've not felt compelled to cut back.
I have always been told that running can affect
your G Tolerance, but I have been a runner all of my
life, I have run 15 marathons and I lift weights, 5-6
days a week and I have not had a problem with G
tolerance.  I have been flying acro now for close to 8
years and have competed throughout that time.  The
net-net is that being  fit, is always better than not
being fit.  
Most civilian, nonmilitary, planes cannot sustain high G's long enough
for your cardio training to be a factor.  If your acro was in a F-16,
F-18 etc. where sustainable G's are available, weight training would be
an excellent thing to do.
Your are not going to have a problem, It is mostly  with the Unlimited
folks that problems occur.   If you are having problems during a pull be
sure the you tighten the stomach and butt muscles before the pull.
Another helpful hint is to turn your head to the side if you really
start to get light in the head during a pull, this seems to restrict the
neck blood flow.
I fly a S2A.  Run and work out daily - I fly acro three times a week - 3
slots of 45 min per afternoon. I do flight training on weekends - some
doing loops, spins and rolls  - no snaps - in a clip wing.
Been doing the acro for about three years, the running forever and
weights for about four. Currently running doing five miles in 30 minutes
pulse rate tops out at 175. Although 20 years ago I was doing it iin 20
Ted Wheeler does acro and a lot of running (does Iron Man competitions,
believe, and is currently or just recently on Everest so might not
for a while).  He might be able to answer with personal (ie- anecdotal) 
experience.  He's at ted_wheeler at
Also if you haven't already heard from Scott Poehlman (who I bought my
share from), you may want to contact him.  He's an acro pilot and
and is currently writing the Human Factors column in the magazine.  I
have his email but can get you his phone number if you'd like.
Myth.  Myth, myth, myth.
Cardio is GOOD for G-tolerance, as is weight training.  Cardio because
your heart can pump more blood, weight training to help with anti-G
straining maneuvers.
I am the IAC Human Factors Chair, as well as a practicing physician. My
first advice to you about G tolerance is to read the article in the most
recent Sport Aerobatics--which covers positive g tolerance issues. In
Primary and Sportsman, positive G tolerance is really the only issue. It
references an Adivsory Circular (I _think_ AC 91-61, but I don't have
the references here in front of me)--go get that AC--you can get it off
the AOPA web site.
As far as training is concerned, the "classical wisdom" in aerobatics is
that strength training, particularly lower body strength training
improves positive G tolerance, while aerobic conditioning, such a
running, particularly long distance endurance running impairs G
tolerance. This makes very good sense from a theoretical basis, since
aerobic endurance training increase vagal tone and lower heart rate, and
intrinsically lowers resting blood pressure.  All of these are important
compensatory mechansisms in the response that allows tolerance to
positive Gz.
Fortunately (or un-...) none of this theorizing is borne out by actual
data. In the studies that have been published looking at exercise and G
tolerance to date, no one has seen an increase in positive Gz tolerance
as a result of strength training, NOR have they seen a diminution of G
tolerance when subjects are aerobically trained. I am presently working
with a personal trainer and exercise physiologist here in Austin, and
you'll see a more detailed answer to this question sometime in the Fall
in Sport Aerobatics.
For the present, my advice has to be something like this: "I wouldn't
radically change my exercise program and expect my G tolerance to remain
the same. However, if you have a program that works for you and you are
able to maintain reasonable G tolerance, then press on, because it is
better to exercise than not."
Hope this help--if I can give you any further info, please feel free to
e-mail me directly.
I have competed in bodybuilding and in cycling and speedskating at the 
national level for many years. I compete in Advanced category (Sukhoi
and Pitts S1T).  
In my experience, the weight lifting increases G tolerance.  Aerobic
has not adversely affected my G tolerance ,possibly due to the weight 
lifting. I am used to +7/-5 in the Suke and +6/-4 in the Pitts.
from a long aerobic training session will  lower G tolerance
Capillarization anaerobic (lactate) workouts can cause some pooling of
This would be a workout such as one legged squats  X  50 reps each leg
at a 1 
/sec pace with a new set each minute, done for 30 to 60 minutes
This ruins my G tolerance, so I don't even do them until after aerobatic

season is over.   Extra body weight lowers G tolerance. caffiene lowers
tolerance.  Heat does too, even when well hydrated. Keep  your training 
going!  If you have no problem with +6/-4 in the S2 C, that's all you'll
My experience is to fly acro before you exercise if you are doing both
on the same day and stay hydrated.  When flying, if you pull hard and
see "stars" just call it a day and land because you are too fatigued or
dehydrated.  If you feel tired before you fly, just don't fly.  Being
younger also helps.
I used to run 60 miles/week and if I flew after running, even later in
the day, it just did not work for me.
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