Hello,
I thank you Belgian Waffle for posting this question as I am finding the question (and responses) quite interesting. Why not open up this issue to a wide audience and hear what others have to say? I am glad you have been checked out medically with no issues noted.
Since this only happens to you after very long flights, I think it may have to do with the dry environment. As we all know:
"The air at altitudes of 30,000 to 35,000 feet, where most commercial airlines fly, is extremely dry, and the recirculation systems used in airplane cabins dry the air out even more. The lack of humidity sucks moisture from the tissues of the nose and mouth, compromising the body's natural defense system."
It is stressful on the body to fly, especially for such long periods, and your body may be more sensitive than most to this condition. For future flights, I would go above and beyond to stay hydrated.
Meaning:
- No alcohol/caffeine a few days prior to the flight, during the flight, and the day after the flight (while your body adjusts).
- Drink lots of coconut water the day/evening before (electrolytes), and buy some in the airport to take with you on the plane.
- Drink at least one glass of water per hour on the flight (when you are thirsty, your body is already dehydrated).
- Bring your own water on the plane if the airline doesn't provide (or runs out of) extra bottles of water. If you have to urinate a bit more often, so be it.
Hydration is also good to prevent DVT (plus taking a baby aspirin the night before the flight and the day of the flight if you don't have problems with aspirin). Compression socks, too.
Anything you can do to boost your immune system would also be good (the obvious - plenty of sleep, proper diet, boost your vitamin C by eating some oranges, lots of fruit and vegetables, juicing, maybe some supplements if you are open to that, probiotics.)
I don't know what preparation you make before long flights, but if you don't already do any of the above you may wish to try for your next flight and see what happens.
I just got back from Australia (14 hour flight and 10 hour flight, each way) and it certainly is tough on your body to fly for so long even in business class lying in a pod.
