Question 1

What is altitude sickness, and how do you acclimatise?

Accepted Answer

Illness caused by **reduced oxygen availability at altitude**, and the single most important fact about it is that **fitness does not protect you** — it affects people unpredictably, and the main determinant is how fast you ascended.

**Why it happens.** Atmospheric pressure falls with altitude, so although the air is still 21% oxygen, each breath delivers fewer oxygen molecules. The body compensates by breathing faster, raising heart rate and, over days, producing more red blood cells — but the adjustment takes time.

**Acute mountain sickness (AMS).** The common form, typically appearing above around 2,500m. Symptoms are headache plus any of nausea, fatigue, dizziness, and poor sleep. **It is frequently mistaken for a hangover, dehydration or exhaustion**, which is why it goes unrecognised.

**The two serious forms**, which are medical emergencies:

**HAPE** — high altitude pulmonary oedema. Fluid in the lungs, causing breathlessness at rest, a cough, and extreme fatigue.

**HACE** — high altitude cerebral oedema. Fluid in the brain, causing confusion, loss of coordination and altered behaviour. **The inability to walk a straight line is the classic warning sign**, and confusion means the person cannot assess themselves — so companions must.

**Both require immediate descent**, which is the definitive treatment for all altitude illness.

**How acclimatisation works.** Slow ascent gives the body time to adjust. Common guidance suggests, above around 3,000m, limiting the gain in **sleeping altitude** to a few hundred metres per day, with a rest day every few days, and following **"climb high, sleep low"** — daytime ascent above your sleeping altitude promotes adaptation.

**What does and does not help:**

**Descent works.** Nothing else reliably does.

**Acetazolamide** is used to assist acclimatisation, on medical advice.

**Hydration and avoiding alcohol** help, and neither prevents altitude sickness.

**Fitness does not prevent it**, and fit people frequently ascend too quickly for exactly that reason.

**Never ascend with symptoms**, and never leave someone with symptoms alone.

This is general information — seek medical advice before travelling to altitude.

Question 2

What is DVT on long flights, and does anything actually prevent it?

Accepted Answer

Deep vein thrombosis is a blood clot forming in a deep vein, usually in the leg. Long-haul travel raises the risk modestly, and the mechanism is better understood than the folklore around it

Question 3

Why does airline food taste bland?

Accepted Answer

Because your sense of taste genuinely changes at altitude. The food is usually seasoned more heavily than restaurant food, not less — you simply cannot taste it properly. Three things happen in a

Question 4

Why do planes cruise at around 35,000 feet?

Accepted Answer

Because it is the altitude where fuel efficiency, weather avoidance and engine performance balance best. Fly lower and you burn more fuel; fly much higher and the engines run out of air. Thinner air

Question 5

How does cabin pressurisation work, and why do oxygen masks drop?

Accepted Answer

Because the air at cruising altitude is far too thin to breathe, the cabin is artificially pressurised — and the masks exist for the brief window in which that pressurisation is lost. The problem

Question 6

Can you fly while pregnant, and what are the airline rules?

Accepted Answer

Generally yes, and flying is not considered harmful in an uncomplicated pregnancy — but airlines impose their own limits, and those limits exist mainly because they do not want a birth on board

Question 7

What health precautions should I take before traveling internationally?

Accepted Answer

Taking health precautions before international travel is essential for safety. Consult a healthcare provider, get necessary vaccinations, and pack a health kit.

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