Hi

Does the pressurization / relatively short time between changes in atmospheric pressure have any impact on the body and it's internal workings? I find that on my flights I start to rip some nasty farts coming out of 8,000 feet or so. This subsides until initial descent. Is there a substantial difference in pressurization between different aircraft? I get headaches during the descent stage on the older SWA 737's and usually rip the nastiest farts on MD-88's.

PEK777 wrote:

I find that on my flights I start to rip some nasty farts coming out of 8,000 feet or so. This subsides until initial descent.

The linguistic skill required for that sentence is incredible.

You might want to fly on the 787 instead. On the other hand, from your post I can't tell if "ripping nasty farts" is supposed to be a good thing or a bad thing.

Not a doctor here but I have some basic understanding because I have taken a flight physiology class. In a slow but unplanned depressurization passengers may feel some discomfort and the normal side effects of reduction of pressure. Use of oxygen masks should help these symptoms.

In the case of an explosive depressurization the cabin will fill up with condensation and lose objects will go flying which can be dangerous to passengers. Getting sucked out if you are a passenger is unlikely but has happened. This of course would result in death. Assuming a passenger stays in the aircraft (they almost always do) they can sometimes experience a burst eardrum and unconsciousness. At 35000 feet a person in perfect health can assume a 30-60 second Time of Useful Consciousness (TUC) which is how long a person will be able to function effectively and cognitively ASSUMING PERFECT HEALTH. If a person is a smoker or is drunk they can cut their TUC in half. Because of this short TUC it is important for crews to have quick donning oxygen masks. During the depressurization passengers all of the air will be forced out of the passengers lungs and this can cause lung damage if the depressurization is violent enough. The ear drum issues and the lung issues happen within 5 seconds of the depressurization. After this is it imperative that passengers don oxygen masks before exceeding their TUC as if they do they will become unconscious.

I hope that helps. I'm only familiar with the effects on the body of an explosive depressurization. If you want info on a normal depressurization I won't be able to help you with that. Hope that helped!

kabq737 wrote:

In the case of an explosive depressurization the cabin will fill up with condensation and lose objects will go flying which can be dangerous to passengers.

I don't think this was the kind of "explosive depressurization" the OP had in mind. Dangerous to passengers, certainly. As for loose objects, not gonna touch that one.

AirstairFear wrote:

kabq737 wrote:

In the case of an explosive depressurization the cabin will fill up with condensation and lose objects will go flying which can be dangerous to passengers.

I don't think this was the kind of "explosive depressurization" the OP had in mind. Dangerous to passengers, certainly. As for loose objects, not gonna touch that one.

Haha I was also skeptical of that one but that's what I was taught. It's possible it's wrong because it seems unlikely.

I recently flew EK BCN - DXB, and I had ordered a vegetarian meal. I ended up with a vegan meal that was at least 50% legumes (by volume). While very nice, it made for an unpleasant DXB - TPE flight, with a great deal of very ominous gastric rumbling and increased gaseous emissions. I sincerely hope that the emissions were not too obnoxious, for the sake of those around me.

It does seem to me, from my pretty regular flying, that being at altitude, and the associated lower atmospheric pressure, does allow the gas produced by the gastric flora to expand more rapidly and require more frequent release. I don't think that the flora produce any *more* gas, just that the pressure differential allows it to expand more.

I definitely have some bloating issues on long flights. Not so much on short flights, but flights of 5+ hours can be problematic.

It makes sense. I've seen bags of potato chips actually explode in the overhead bins. I've had containers of shampoo do the same (before the 3 ounce rule). Stuff expands up there. It would be the same if you were climbing a mountain, I'm sure. The human body gets used to whatever altitude it's actually at most of the time. Maybe people in Denver don't have much of this issue, because they're already at 5,000 feet, so going to 8,000 feet cabin pressure isn't a big deal. But going sea level to 8,000 feet and staying there for 5+ hours will definitely start to expand whatever gas you have inside you. This is exacerbated by whatever food you eat up there; basically all food naturally produces at least some gas. I try to minimize the intake of food I know will be the worst offenders when I'm up there.

I think this is the real reason airplanes recycle their air 100% about 10 times per hour

I once suffered greatly on a Virgin Atlantic flight to JFK due to a young man lying flat on his stomach in "upper class". As he slept, he didn't stop farting for 6 hours. I have PTSD from the experience. I will always fart once or twice during a flight, and certainly my feet expand - it's very difficult to put my shoes back on (I always wear the socks to help control the swelling. Aside from this, DVT's can happen during flights and the medical community believes air pressure changes coupled by stagnant legs movement, it is very dangerous and very rare, but it happened to me in the late 1990's- landing me in the hospital for 9 days. Yes, funky things happen to your body.

I find exactly the same on older 737s, to the point where I began to avoid them if possible. Not too sure of the cause.

I also find the 747 leaves me feeling especially dry and 777 particularly fatigued.

Funniest was on an A380 just after EK had started flying them. DXB-SYD (14-15 hours) non stop full load with lots of extremely tasty curry and beans on the menu. Downstairs forward cabin, almost no engine noise at all and then another five hours with the entire flight impounded by Australian Quarentine on board. You can imagine.......

How do soda cans not explode?? I have always wondered that!

Also, not a doctor but some years ago I found a very good article about that subject.

The body adapts to the new ambient pressure and hence lower partial pressure of the oxygen. makes it harder to grasb. This adaption process takes about 2 hours and causes some fatigue, like an easy jog during that time, so one will feel tired. As this process takes some time short haul crews with stakes length below 2 hrs will feel more fatigue as their body is constantly trying to adapt, back during transit and forward again on the following leg and so forth. This is also why one feels so tired after a short hop but less after a longer flight.

Due to the lower ambient pressure all gases in the body will expand and will find a way out of your body, either direct or via your metabolism and exhaling. Planes with a higher cabin pressure eg. B787 and A380, will put less stress on your body as the diffrence between before and after is smaller. Dryness and fatigue one will find rather on older models. Here the air is fully exchanged and rather dry, wereas newer models recycle, filter the air and add just a fraction of fresh (dry) air. So the level of moisture is higher and give more comfort.

As for your nasty frts, is nasty the volume or the smell? If the smell persists, see you doctor. Maybe your colon bacteria need a tune up. This should also take care of the volume.

But hey, its a mans world

I often have this problem as a pilot. After a long day at work (8-10 hours in the air), my body feels bloated for hours after I get home from work and I am farting more. Not the nasty kinds of farts though lol

AZa346 wrote:

How do soda cans not explode?? I have always wondered that!

The same reason the big soda cans do not explode. The material is strong enough to carry the load.


David

Hi all, this is my first post after being here for 10+ years. I hope you find this useful.

I went through the US Air Force's training for enlisted flight medics (they like to call it "Aerospace Medicine Specialist"). We had to be quite well versed in the atmosphere's effects on the body. It's been a long time (20+ years), but here's what I recall:

Any gas that is "trapped" somewhere in your body will expand as you ascend (decreased pressure). For most folks, the effects are most obviously demonstrated by intestinal gas. I think most folks get this intuitively if not by personal experience. However, people can also run into problems with air trapped in their sinuses, ears, and their teeth (certain circumstances of cavities), and probably elsewhere.

At altitude, the bigger concern is that the atmosphere is hypobaric and hypoxic, so you have less pressure driving less oxygen across the lung's tissue. There are a number of disease states that can be exacerbated by this. Many of these diseases arise from the pulmonary or cardiovascular systems (very oxygen sensitive).

One thing that does not seem to be impacted by altitude (but is often blamed for it) is a blood clot (DVT / PE). The clots can be fatal, so they have to be taken seriously, but they are thought to be more likely a function of immobility and perhaps dehydration than anything else (look up Virchow's Triad). Despite their "coach class syndrome" moniker, these clots can happen in any class of service. My recollection from training is that air crew do not have higher rates of clots than passengers, so that is part of the basis for thought leaders not suspecting the altitude itself.

For those with particularly nasty ear or sinus (drainage) problems, the decent can be the most painful phase of flight. It can range from discomfort all the way to ruptured ear drums.

Anyway, there are actually medical guidelines freely available on the web. They are written by medical professionals for medical professionals, so keep that in mind. I'll link to the guidelines. https://www.asma.org/publications/medical-publications-for-airline-travel/medical-considerations-for-airline-travel

Regards
Gumby

PEK777 wrote:

Hi

I find that on my flights I start to rip some nasty farts coming out of 8,000 feet or so.

That's a feature, not a bug!

spacecadet wrote:

I definitely have some bloating issues on long flights. Not so much on short flights, but flights of 5+ hours can be problematic.

It makes sense. I've seen bags of potato chips actually explode in the overhead bins. I've had containers of shampoo do the same (before the 3 ounce rule). Stuff expands up there. It would be the same if you were climbing a mountain, I'm sure. The human body gets used to whatever altitude it's actually at most of the time. Maybe people in Denver don't have much of this issue, because they're already at 5,000 feet, so going to 8,000 feet cabin pressure isn't a big deal. But going sea level to 8,000 feet and staying there for 5+ hours will definitely start to expand whatever gas you have inside you. This is exacerbated by whatever food you eat up there; basically all food naturally produces at least some gas. I try to minimize the intake of food I know will be the worst offenders when I'm up there.

I think this is the real reason airplanes recycle their air 100% about 10 times per hour

Ah, the lowlanders of Denver. I live at 6500 feet and work at 8400 feet. While I might rip some nasty ones on my morning drive, I'm not sure any of that is due to altitude change.

Driving to/from work with a head cold though, that can be brutal.

I nearly always need to take a dump after a longish flight, but maybe that's the airline food more than air pressure!

Hope this helps.
When you're flying, your body pressure is about the same as sea level (assuming you're living on a sea level). When you climb, the pressure outside decreases so there are differential pressure between your internal cavities and external air. Because the internal cavities is pressurized approximately same as sea level air pressure, the resultant effect is the gas inside the intestinal cavities expanding. There are two exit routes for intestinal gas, farting or burping, which can happen in flight, especially during ascent phase where body is still at sea level and trying to adjust to reduced outside air pressure.
Deep Vein Thrombosis (DVT) occurs mainly when blood is stagnant for a long period, increasing the risk of forming clots. The way to prevent blood clots is basically avoiding any blood stasis, by walking to the lavatory every couple of hours and doing some exercises as found on inflight magazines. It will help. If you're particularly at risk for thrombus formation, you can ask doctors for warfarin or aspirin prophylaxis before flight to prevent blood clots forming. It's a prudent idea to consult to your physician before taking long flights, especially if you're at increased risk. Big veins are usually low in blood pressure and relies on muscle contractions to pump blood back to heart, that's why exercises is important to pump the blood collecting in your legs back to your heart.
Because the fluid from tissues are not only drained from veins but also lymphatic system, the story is same. Lymphatic system relies only on muscle contractions and fluid tends to collect in lowest part of body, so without leg movement for a long period the fluid will collect in legs. The effect is cumulative between the vein and lymphatic system. You can observe this phenomenon (leg swelling), though not that extreme, by measuring the size of your legs at the morning and at night. Your leg will increase in size because the fluid is collecting in leg tissues and increases its size. That's why it's recommended to measure and buy shoes at night, cause your leg is in the largest size.
As for ear canal pressure equalization, I prefer Toynbee maneuver myself. It clears your ear more effectively than Valsalva maneuver, combined with less risk of over pressurizing the middle ear, increasing comfort and reducing pain from Valsalva maneuver. Both can be used as effectively to maintain equal ear pressure, though.
Basically what gumbyn said is right.

Something I remember from an EMT textbook is that blood pressure measurements taken on aircraft are very often wrong.


David

andymartin wrote:

I nearly always need to take a dump after a longish flight, but maybe that's the airline food more than air pressure!

Sounds like you're not able to handle the load like a soda can....

flyingturtle wrote:

Something I remember from an EMT textbook is that blood pressure measurements taken on aircraft are very often wrong.

I'm what way are they wrong? Do you mean it's always higher or lower than normal or is the blood pressure measurement at altitude not indicative of what the body is experiencing?

Oilman

I'll add to the growing consensus here - up on planes that are pressurized, farts tend to find their way out more frequently... and this corresponds to the fact that the volume of gas is pressurized to sea level on the ground. Once we're up in the air (pressurized at roughly 8,000 feet), atmospheric air pressure drops from roughly 15 PSI of atmospheric pressure to roughly 10 PSI if the plane is pressurized around 8,000 feet. Any gasses inside you - will, by virtue of the sudden decrease in pressure, actually INCREASE the outward/expanding in pressure inside your body, and work their way out.

Wow...this is some thread indeed!!

Yes, while I am personally not affected by "added farting" whilst flying, I am indeed aware of the large amount of intestinal gases being passed by some passengers on long flights, to the extent of once having had a bitter argument with a neighbor because of said reason. She was constantly passing nasty air so much she was making the flight for her immediate residents a real stinking inferno.. Of course she denied any allegation, and silently kept farting her venomous wind for the remainder of the flight. I swear the entire seat was enveloped in a cloud of bad odour when she finally got up in AMS. Awful.

I am personally more seriously affected by the dry air, and always end up being really dehydrated despite drinking colossal amounts of water. I get particularly dry lips and face skin, and have to use a lot of lotion/cream and lip balm during long flights. I also find the 777 and older 747s particularly "tiring' on the body.

On a more..errr.. personal level, I invariably notice that my "junk" gets affected by flying- not sure whether it's induced by a change in body temperature or by pressurization, but I tend to get very low hanging testicles and a shrunken penis during long hauls. Any other man has noticed this? Yes, it's a man's world I guess...

Oilman wrote:

flyingturtle wrote:

Something I remember from an EMT textbook is that blood pressure measurements taken on aircraft are very often wrong.

I'm what way are they wrong? Do you mean it's always higher or lower than normal or is the blood pressure measurement at altitude not indicative of what the body is experiencing?

Oilman

Basically, what sphygmomanometer measures is the difference of pressure between your body and the outside air. Reduced air pressure in the cabin means the differential pressure is different between what is really is. I think aneroid sphygmomanometer is more prone to error than mercury ones. I think the aneroid shygmomanometer will show higher blood pressure than what really is though I never tried that by myself.