How to Stay Hydrated on a Long-Haul Flight
Why Hydration Matters at 35,000 Feet
The cabin air on a long-haul flight has a humidity level of around 10–20% — far drier than most desert environments. That means your body loses moisture faster than you realise, leading to dry skin, fatigue, headaches, and even impaired concentration. Staying properly hydrated isn't just about comfort — it's essential for your health and performance when you land.
How Much Water Should You Drink on a Flight?
A general rule of thumb is to drink at least 250ml (one cup) of water for every hour you're in the air. On a 10-hour flight, that's around 2.5 litres — significantly more than your usual daily intake. Avoid waiting until you feel thirsty; by that point, you're already mildly dehydrated.
What to Avoid
- Alcohol — it accelerates dehydration and disrupts sleep quality in-flight.
- Caffeine — coffee and energy drinks act as diuretics, increasing fluid loss.
- Salty snacks — they increase your body's need for water without providing it.
Tips to Stay Hydrated on Your Next Long-Haul Flight
- Bring a refillable water bottle — fill it up after security and ask cabin crew to top it up regularly.
- Use a hydrating nasal spray — dry cabin air affects your nasal passages too.
- Apply a quality moisturiser — skin hydration matters as much as internal hydration.
- Opt for herbal teas — a caffeine-free hot drink can supplement your water intake.
- Consider an electrolyte supplement — electrolytes help your body retain and absorb water more effectively, making every sip count.
The Role of Electrolytes in In-Flight Hydration
Drinking plain water is a good start, but electrolytes — minerals like sodium, potassium, and magnesium — are what allow your cells to actually use that water. When you're in a dry, pressurised cabin, your body loses electrolytes faster than usual. An electrolyte supplement taken before or during your flight can make a significant difference to how you feel on arrival.
At Mach, our supplements are formulated with travel in mind — supporting hydration, energy, and recovery so you land feeling your best, not your worst.