Exercise after Flight: Dangerous?

[Threethirteen]

Is exercise after flying hazardous to the health of the average person?:confused:

Should we abstain from working out for a minimum time after chocks, or is this an old wives' tale?:hmm:

Thanks.

313;)

[Bob the Doc]

Not aware of any reason whatsoever why one should not exercise after flying

Think it must be an old wives tale. If anyone has a good reason why I might be mistaken I am happy to be corrected!

[tolisshow]

i think exercise before flying is the dangerous fact and reduces pilot s performance and health

[Bob the Doc]

Why should exercise before flying be detrimental? I can understand that if you are dehydrated after exercise this will reduce your tolerance to G and that an exhausted person should not fly but if you are just cycling 10 miles to the airfield or having a game of squash before flying (as examples) I don't see why this should affect your performance. Conversely, I would have thought that flying straight after a high carb, high fat meal is probably much worse! I certainly need a nap after a meal like that and wouldn't want to call myself fit to fly!

[777fly]

Maybe the last 2 posters need to RTFQ?
For what it's worth, I have been a regular runner, squash player, swimmer and gym rat during a flying career spanning 1967- July 2009. I have never found that exercise straight AFTER a flight is easy or feels beneficial. Strangely, it is the same after multiple or early short haul or 12+ hours of longhaul. Maybe this is just my own mental and physical response, but I have always allowed overnight rest or several hours sleep before physical exercise after flying and have always not only felt better, but performed better during exercise too.

I do believe however, that any form of exercise before a flight is highly beneficial and should be done whenever possible. I feel that some physical pre-toning is a great preparation for the following hours of relative inertia and considerably enhances mental awareness.

[Threethirteen]

Thanks very much for the informative replies. :ok:

My next question was going to concern differences between multi-sector pressure cycles and sustained periods at altitude, so that's covered too.:)

The issue of rest and/or sleep in between end of duty and start of exercise is what continues to interest me; is this a blood pressure issue or simply one of fatigue?

[Bob the Doc]

777fly

I DID RTFQ!

I think you will find that I replied to the original question in my FIRST post. My second was a reply to the comment from tolisshow.

BtD

[gingernut]

Sorry, haven't worked out what RTFQ stands for.

I'm trying to work out, physiologically, why exercise after flying could be dangerous. Or perhaps what stands pilots out from the rest. Apart from the oxygen saturation thing, and the Boyle's law stuff, (which reverse quickly when on the ground),I can't see any reason why exercise is anything but beneficial.

The usual rules should apply, don't exercise if unwell, etc etc.

Probably not a good idea to go jogging with your pay packet in your pocket also-could cause a nasty sprain.:}

[Bob the Doc]

GN

From memory, RTFQ means Read The F@@**ng Question

BtD

[Pace]

I would imagine strenuous exercise after flight could be dangerous.

I have flown a lot in unpressurised twins sometimes up to 14000 feet unpressurised and without oxygen. Regularly up at 12000 feet without oxygen and up to 20000 feet with oxygen. I have also flown a lot in pressurised corporate jets.

We all know that your night vision is effected at 5000 feet so even in a pressurised aircraft over a long flight there must be effects?

How long the body takes to return to normal levels after landing? there are people better placed to answer in this forum.

I was told and this could also be an old wives tale that alchohol has a worse effect at altitude if you are a passenger consuming alchohol in a pressurised aircraft.

I was also told that the blood get thicker with a change in balance between red and white corpuscles (prob spelt that wrong) and that it is advisable to take an aspirin before high altitude flight?

I believe the heart works harder at altitude and blood pressure increases so any strenuous exercise straight after landing would not be advisable?

There are other changes! as a current Scuba diving enthusiast I know that every 33 feet in depth the pressure increases by 14.7 ibs psi or one atmosphere.

Divers breathing compressed air have a high level of nitrogen in the blood stream. This only returns to normal on the surface after quite a period of time. hence multiple dives can cause a major problem witrh no decompression limits.

In the same way although in reverse flying at altitude even in a pressurised aircraft for long periods of time will mean a decrease in sea level nitrogen levels as well as oxygen levels meaning an upset in the normal blood chemical balances.

after diving you cannot fly for at least 12 hrs.

While diving and flying are different and the effects also very different, the absorbtion of nitrogen in the system is pressure related. Increased as well as decreased.

I would imagine after flying it would also take time for the chemical blood balances to return to normal and while maybe strenuous exercise is ok for a young fit person maybe not so good for an older not so fit person.

My guess is that it would not be a good situation to be enjoying strenuous exercise straight after a long flight in even a pressurised aircraft.

Any answers from those that know??

Pace

nb just found this link which may be of interest

Effects of high altitude on humans - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Effects_of_high_altitude_on_humans)

[Bob the Doc]

Pace

To answer your questions in order...



We all know that your night vision is effected at 5000 feet so even in a pressurised aircraft over a long flight there must be effects?

Perhaps but don't see how this affects exercise (except jogging at night!). From memory, loss of night vision is likely to be a hypoxia effect so it should resolve pretty immediately on coming back down to normal oxygen levels anyway

I was told and this could also be an old wives tale that alchohol has a worse effect at altitude if you are a passenger consuming alchohol in a pressurised aircraft.

Alcohol worsens the effect of hypoxia (as both cause deterioration in brain function). Even at 8000 feet cabin alt, these two effects are still significant enough. Another reason why the semi-drunk get bumped off flights!

I was also told that the blood get thicker with a change in balance between red and white corpuscles (prob spelt that wrong) and that it is advisable to take an aspirin before high altitude flight?

Long term exposure to high altitude (well, more accurately, low oxygen tensions) causes something called polycythaemia (an increase the number of red blood cells) to increase the blood's oxygen carrying capacity. The increase in red cell mass makes the blood thicker (more viscous) and increases the risk of clots. Aspirin makes cells less sticky (although it's the platelets and not the red cell that become less sticky)

Short term exposure does not cause the same thing (as red cells take quite a while to be made). Dehydration (caused by inadequate intake of fluids, dry air in the aircraft, possible alcohol intake) can make the blood a little thicker so in theory the clot risk is increased. Aspirin probably reduces the risk of clots but the risk of side effects is probably more. If your risk of clotting is significant then you should seek medical advice about getting alternative treatments (like low molecular weight heparin (LMWH)).

I believe the heart works harder at altitude and blood pressure increases so any strenuous exercise straight after landing would not be advisable?

The heart does work harder at altitude. This increase in Cardiac Output (CO) is to increase the oxygen transport to the tissues. Again, this increased work is not required when back on the ground. Might be why people report feeling a little more easily tired after a flight though.

There are other changes! as a current Scuba diving enthusiast I know that every 33 feet in depth the pressure increases by 14.7 ibs psi or one atmosphere.

Correct

Divers breathing compressed air have a high level of nitrogen in the blood stream. This only returns to normal on the surface after quite a period of time. hence multiple dives can cause a major problem witrh no decompression limits.

Also correct. The increased dissolved nitrogen takes some time to come out of solution

In the same way although in reverse flying at altitude even in a pressurised aircraft for long periods of time will mean a decrease in sea level nitrogen levels as well as oxygen levels meaning an upset in the normal blood chemical balances.

Correct(ish). It's the formation of bubbles in the bloodstream if the nitrogen comes out of solution that cause the problems. Not the chemical effect of the nitrogen (this is an issue at depth with Nitrogen Narcosis). It is, however, true that the amount of dissolved nitrogen after a period of decompression (altitude) will be less but the change is generally insignificant. You would have to rapidly decompress to high altitudes to get the bubble formation that causes the Bends

after diving you cannot fly for at least 12 hrs.

This is an absolute minimum. I would suggest at least 24 hours or more would be more appropriate, depending on the depth you dived to. 8000 feet cabin altitude is about 70% (can't remember the exact amount) of sea level pressure so the change is usually not significant but if you are effectively rising from 2 atmospheres (10 metres diving depth) then the relative change is much larger and the bends can ensue.

I would imagine after flying it would also take time for the chemical blood balances to return to normal and while maybe strenuous exercise is ok for a young fit person maybe not so good for an older not so fit person.

Not really. Nitrogen has a minimal chemical effect at normal pressures. It is the physical effect of the bubbles that causes the problem as mentioned above

Hope that helps. Sorry for the long post

BtD

[Pace]

there are people better placed to answer in this forum.

BTD Thanks for clarifying these points so well

Are there any benefits in taking an aspirin for flying a non pressurised aircraft? Just as a side issue The FAA stipulate up to 12500 feet ad infinitum and 12500 to 14000 feet for 30 mins which is more lax than the European regs.

Pace

[Bob the Doc]

Pace

Not an expert on Venous ThromboEmbolism (VTE) but from the knowledge that I do have, managing the risk is better done physically than chemically. Obviously, in smaller aircraft, some of this is a little more challenging than in airliners but here goes...

Maintain hydration - multiple benefits here but part of it may be a reduction in risk of VTE. Certainly, the increased requirement to go to the loo helps with...

Keep mobile - one of the causes of venous stasis in the legs (where nearly all Deep Vein Thromboses (DVTs) originate) is immobility, especially if the venous drainage is further impeded mechanically. Pregnant people have a large mass pressing on their pelvic veins which causes them increased risk but just sitting (especially if you are cramped) increases the obstruction to venous outflow and increases the chance of DVT. Sitting cramped and immobile for a long time (imagine a cattle class flight to the West Coast of the US for instance) is especially bad. Try and get up and move around. There are various devices available that may or may not work (graded compression socks, pillows you 'knead' with your feet etc). I appreciate that moving around a small aircraft is nigh-on impossible and I am afraid I don't know enough about how much rudder action your legs get (I suspect not much at all if you have trimmed the a/c well!) on longer flights but trying to keep your legs moving every so often will certainly help.

Avoid constricting clothes. These can increase the obstruction to flow. Wear socks without tight bands at the top. Consider removing belts from trousers and/or undoing the top button. If you have imprinted bands on your skin after flying, your clothes may be too tight there!

As I have said before, I remain to be convinced that for people with a normal risk of DVT (no predisposing medical condition), aspirin makes any real difference at all. LMWH (see other comment) certainly reduces your risk of DVT but the other advice probably reduces it as much, if not more.

The pressure effect of higher altitude is likely to make a very small difference to the risk of DVT I would have thought but am happy to be corrected by a more qualified aviation physician.

It's called economy class syndrome for a reason. I haven't heard of many aircrew getting DVTs. It's the pax that seem to get them!

Happy flying

BtD

PS...if you're flying unpressurised fast jets then you should be fine. The pumping action of the G-trousers should mean that the blood flow is kept good!

[Pace]

PS...if you're flying unpressurised fast jets then you should be fine. The pumping action of the G-trousers should mean that the blood flow is kept good

No my normal transport are unpressurised piston twins, pressurised turbine twins and corporate jets, so no unpressurised fast jets :)

Pace

[gingernut]

what happened to the rant? I was quite enjoying it.

[Pace]

Gingernut

Sadly I think he removed his own post and left the pprune forum for the Daily Mail one where the true experts abide.

Obviously not enough good information here for him mine was cr_p but the rest i thought was very informative :)

Pace

[gingernut]

Oh well, back to Jet Blast:}