Pulling Gs: Is it good to be short and fat?

[Bernie Kosar]

I’ve read that being in good shape allows you to pull more Gs. Meaning, you will not pass out as easily if you are in good shape (I believe it was in the “Pilot’s handbook of Aeronautical Knowledge”). According to a Naval Aviator in this video (link below) short, fat guys with high blood pressure can pull more Gs without passing out? What do you guys think? I’d like some other opinions……

http://video.google.com/videoplay?docid=5970999225038103880

 

[nittany03]

I think the guy in the video was being somewhat facetious. Granted, the flight docs actually recommend not running more than 20 miles a week for just this reason. It lowers your blood pressure too much. I've also heard of being shorter helping, but I still don't get how being stocky or barrel-chested, let alone fat, helps G-tolerance. If you can think of the blood supply between your heart and your head as a column of liquid, the G force will try to drag it down. The higher your blood pressure, the greater the force resisting that and keeping blood flowing up. Also, the shorter that column, the easier it is to push the smaller quantity of liquid up to your brain.

There is also a cardiovascular reflex which kicks in when you go under about 5 seconds or more sustained G. You heart starts pumping harder to move more blood up to your brain, so aerobic conditioning will help there. Strong legs also help your AGSM. More muscle tension allows more blood to be squeezed out of your legs. Overall strength is also important just to move around in the cockpit and try to find the other guy. I'm sure the Hornet folks can speak more to this, but I was amazed how hard it was to keep sight on my first defensive sets in the Goshawk, and that was just 3-4 Gs sustained. Note that the Blues, who pull Gs without any mechanical assistance, tend to be fairly muscular guys.

I need to find a source for this, but I believe the Air Force actually did a study after the Gulf War which indicated that though the heavy weightlifters could pull the most G, it was the medium-distance runners who were the best over the long haul because their endurance training aided their recovery time without compromising their blood pressure. They could fight more often without getting as worn out.

Also, the more G you pull, the more your body will get used to it. Your tolerance will go up if you fly dynamic flights on a regular basis. Come back after a couple weeks of not pulling any Gs, and you will wonder where your tolerance went.

 

[Gatordev]

Nit,

It's because you don't have to work as hard to keep your hydralics at the same pressure. Longer, skinnier guys (like me) have longer plumbing, but since we all have the same amount of blood, it takes more effort to keep the blood where it needs to stay (ie maintain the pressure). Mind you, this is a very simple, gatordev-speak, explaination. I'm sure Feddoc can hit you with actual techical terms and "facts."

 

[scoober78]

since we all have the same amount of blood

Just a minor point, but I'm pretty sure thats not true. I mean the average is 5 to 6 litres but it varies with size and some other variables.

I've always heard the explanation about blood pressure that nittany pointed out. The lower your resting BP the harder it is to maintain blood flow under G's...

 

[Gatordev]

Just a minor point, but I'm pretty sure thats not true. I mean the average is 5 to 6 litres but it varies with size and some other variables.

I've always heard the explanation about blood pressure that nittany pointed out. The lower your resting BP the harder it is to maintain blood flow under G's...

Like I said, other people might bog you down w/ "facts." Could be, but generally, tall, skinny guys will have a lower blood pressure than more rotund guys. Not saying one is healtier than the other, just lower. The basic reason is hydralics, which I was trying to convey above, albeit poorly.

 

[scoober78]

Like I said, other people might bog you down w/ "facts."

 

[skidkid]

it's never good to be short and fat

"Son, Fat Drunk and Stupid is no way to go through life"
-Dean Wormer

 

[feddoc]

Short folks generally can pull Gs better because of decreased head to heart distance. Fat guys usually can't pull Gs worth a darn because of decreased muscle tone.

Running can decrease G-tolerance, most likely because running (to excess) will re-define how your muscle cells react to stimulii. In other words, when you train aerobically, you are telling your muscle cells/fibers to become more effecient at processing more O2 and become a bit less effecient at events which require a high degree of short duration, high intensity exercise.

The point at which aerobic training becomes a problem is ill defined; there is only one study which suggests that running more than 30 miles a week is detrimental to pulling Gs...that study is about 23 years old. My instinct tells me that is about right. This is not to say that any running is bad as you will need some sorty of aerobic base to provide you with sufficient abilty to recover from repeated bouts of high intensity exercise---which is what pulling Gs is.

BTW, an elite weight trained athlete can have a blood pressure that is on par with an elite marathoner, all other things being equal. It is all about the demands placed upon the heart. Aerobic training places a volume demand on the heart while strength training places a pressure demand on the heart. Either way the left ventricle becomes more efficient at pushing blood out to working tissue (aka ejection fraction).

Train like ya' fight...pulling Gs is short duration, high intensity....train your body accordingly.

 

[Carno]

Thanks for the informative post!

 

[pourts]

Come back after a couple weeks of not pulling any Gs, and you will wonder where your tolerance went.

So, pulling G's is just like drinking? Can one be good practice for the other? :tongue2_1

 

[whitesoxnation]

Pete Mitchell is small so it must be true.

 

[nittany03]

So, pulling G's is just like drinking? Can one be good practice for the other? :tongue2_1

Not that I have ever done it, but pulling Gs while hung over should probably qualify as one of the inner circles of Hell . . .

 

[Fly Navy]

Not that I have ever done it, but pulling Gs while hung over should probably qualify as one of the inner circles of Hell . . .

Add a Mexican out-and-in to that and it's like being tortured by Lucifer himself.

 

[MasterBates]

I take it altitude + mexican = bad?

 

[Fly Navy]

I take it altitude + mexican = bad?

Can be, and for some reason, whenever you eat Mexican, you seem to eat TOO much. G-suit pushing on full stomach = the suck.