The health advice given to travellers is dominated by vaccinations and tropical disease, which is appropriate for some destinations and irrelevant to most trips. What actually derails an ordinary holiday is more mundane and much more preventable.
Medication: the border problem
Some medicines that are ordinary prescriptions in one country are controlled substances in another. This catches people out most often with strong painkillers, some sleep medication, and stimulants prescribed for ADHD, and the destinations most commonly involved are Japan, Singapore, the UAE and parts of the Gulf.
- Check the destination's rules for each medication you take, on the embassy's own site, before you fly.
- Carry everything in original labelled packaging, never decanted into a daily organiser for the flight.
- Carry a copy of the prescription or a doctor's letter listing the generic names, not the brand names, which differ between countries.
- All medication in hand luggage, with several days' surplus beyond the trip length.
- Split it. If travelling with someone, put half in each bag.
Refills abroad are harder than people assume. A foreign pharmacy generally cannot dispense against a foreign prescription. If you run out, you need a local doctor's appointment first — which on a Sunday, in a small town, with a language barrier, is a lost day at best.
What actually makes people ill
- Dehydration, by a wide margin. It presents as fatigue, headache and poor decisions rather than as thirst, and it compounds over days. Aircraft cabins are extremely dry, hot ports are worse, and alcohol accelerates it.
- Stomach upsets, usually from unfamiliar food volume and timing rather than contamination. Eat smaller and earlier for the first two days.
- Norovirus on ships. This is the one genuine outbreak risk in cruising and it spreads by hand contact with surfaces, not through the air. Hand washing with soap works; alcohol gel is markedly less effective against this particular virus.
- Sunburn, which at sea and on water is worse than it feels because of reflection and wind.
- Falls. Wet decks, marble stairs, cobbles, unfamiliar bathrooms at night. Among the most common serious travel injuries, and the least discussed.
Aircraft and cabin air
Cabin humidity on a long flight is typically 10 to 20 percent, which dries out the airways and the eyes and is the main reason people arrive feeling terrible. Water, no more alcohol than you would have at home, and saline nasal spray if you are prone to sinus trouble.
For anyone at risk of clots: move every hour or two, avoid crossing your legs for long periods, and ask your doctor about compression stockings before a long-haul flight. This matters more with age and is worth an actual conversation rather than an assumption.
The habits that hold a long trip together
- One rest day a week. Not a travel day, not a light sightseeing day. A day with nothing in it. Three-week trips fail in week two almost entirely for want of this.
- Drink water on a schedule, not on thirst. Thirst is a lagging indicator.
- Protect sleep over sights. A missed cathedral is a small loss; four bad nights compound into an ended trip.
- Eat one familiar meal a day if your digestion is sensitive. Breakfast is the easy one to keep constant.
- Shoes with grip and a stiff sole. The most effective piece of medical equipment you will carry.
- Know where the nearest hospital is in each place you sleep. Ninety seconds of looking, once, on arrival.
The small pharmacy worth carrying
Not a first aid kit — a short list of the things that are needed at 2am when nothing is open: painkillers you know you tolerate, an anti-diarrhoeal, rehydration salts, an antihistamine, plasters, and any personal medication. Everything else can be bought locally in daylight.
Rehydration salts in particular are worth the space. They replace the salts that water alone does not, and they work far faster.
The short version
- Check whether your prescriptions are controlled substances at your destination. Japan and the Gulf are the usual traps.
- Original packaging, hand luggage, surplus supply, split between bags.
- Dehydration and falls cause more ruined trips than anything exotic.
- On ships, wash hands with soap — alcohol gel is weak against norovirus.
- Book one empty day a week into any trip longer than a fortnight.
- Carry rehydration salts.
General guidance, not medical advice. Speak to your own doctor or a travel clinic about your circumstances, particularly regarding vaccinations, clot risk and any long-term condition.