Two long-haul concerns come up more often after 50, and both have real, specific answers rather than vague reassurance: the blood-clot risk everyone has heard of but few explain correctly, and what to do about medication that is supposed to be taken on a strict schedule while crossing several time zones.
Blood clots: what the CDC actually says
The CDC's own guidance is more specific than "get up and walk around," and worth reading in full before a long flight. Anyone travelling more than four hours by any means — air, car, bus or train — has some increased risk from prolonged immobility, and age itself is a real factor: risk rises after 40 and continues climbing with age. Other risk factors that stack with age: a personal or family history of blood clots, recent surgery, active cancer, pregnancy, obesity and varicose veins. For a healthy traveller with none of those, the absolute risk stays low — this is a real but generally manageable risk, not a reason to avoid flying.
The CDC's prevention advice, in the order it is usually given:
- Walk the aisle every one to two hours on a long flight.
- While seated, flex and extend your ankles and roll your feet regularly — the calf muscle is doing the pumping work that a moving body normally does on its own.
- Choose an aisle seat if you can, specifically so getting up does not depend on waking a neighbour.
- Properly fitted, below-the-knee graduated compression stockings are a specific, named recommendation for at-risk travellers — not the same thing as ordinary compression socks bought without fitting.
The CDC's own advice for anyone with additional risk factors is to talk to a doctor about the specific trip before travelling, not to self-assess. That conversation is where compression-stocking fitting, and whether anything else is warranted for that individual's history, actually gets decided.
Medication on a strict schedule, across time zones
This matters most for medication that has to be taken at a consistent time — heart, thyroid and diabetes medicines are the most commonly affected. The American Pharmacists Association's practical approach, and the one worth following:
- Review the medication schedule with a pharmacist or doctor four to six weeks before departure, not the week before — this leaves room to actually adjust a schedule if needed.
- During the flight itself, go by hours-since-last-dose, not the clock on the seatback screen: if a pill is due every 24 hours and was last taken at 8am departure time, the next dose is 24 hours later, wherever the plane happens to be.
- For a time change of three hours or less, most guidance is to simply keep the original schedule rather than adjust anything.
- For a bigger change, shift the dose time by one to two hours a day toward the new local schedule rather than jumping straight to it — a six-hour change this way takes three to four days to fully shift.
- Time-sensitive medications — anticonvulsants, contraceptives and HIV medication are the examples pharmacists flag most often — are where even a one- to two-hour shift can matter, and where the pre-trip pharmacist conversation matters most.
One more practical point that costs nothing to plan for: keep medication in original, labelled containers in carry-on luggage, not checked baggage, on any flight where a delay or a missing bag would otherwise mean missing a dose entirely.
The short version
- Blood-clot risk from prolonged sitting rises with age (starting around 40) and stacks with other factors like recent surgery or a personal/family clot history — talk to a doctor beforehand if any apply.
- CDC advice: walk every 1–2 hours, flex ankles and calves while seated, take an aisle seat, and use properly fitted below-the-knee compression stockings if advised.
- Get a pharmacist's medication-timing plan 4–6 weeks before a long-haul trip, especially for heart, thyroid, diabetes, seizure, contraceptive or HIV medication.
- On the flight, go by hours-since-last-dose, not the clock; on arrival, shifts under 3 hours usually need no change, bigger ones shift gradually over a few days.
- Carry medication in original containers in carry-on luggage, not checked bags.