How to Avoid Travel Dehydration: An Evidence-Based Traveller's Guide

Travel Dehydration also known as Jet lag is the temporary mismatch between your body clock (circadian rhythm) and the local time at your destination. It is not an illness — it''s a normal physiological response to crossing time zones quickly. The good news: with a few evidence-based habits before, during and after your flight, most travellers can reduce how long it lingers.

This article is general information about travel and circadian health. It is not medical advice and does not describe a treatment for any condition. If you have a sleep disorder or take medication, speak to your GP or pharmacist before changing your routine.

What causes jet lag?

Your suprachiasmatic nucleus — a small region of the hypothalamus — sets the body''s 24-hour rhythm using light as its primary cue. When you fly across several time zones, that internal clock takes time to realign with the new light–dark cycle at your destination. The result can include daytime sleepiness, broken sleep at night, low mood, reduced concentration, mild digestive upset and a general "off" feeling.

As a rough rule, your circadian rhythm shifts roughly one time zone per day on its own. Eastward travel is usually harder than westward travel because your day is shortened rather than lengthened.

Before you fly

• Shift your sleep schedule gradually. Two or three days before departure, move your bedtime and wake time 30–60 minutes closer to your destination''s schedule each day.
• Plan your light exposure. For eastward flights, seek morning light and avoid bright light in the evening. For westward flights, do the opposite.
• Arrive well-rested. Don''t board sleep-deprived — it amplifies how rough the first 48 hours feel.
• Pre-hydrate. Cabin air is dry (typically below 20% relative humidity), so start your trip well-hydrated rather than playing catch-up at altitude.

On the plane

• Set your watch to destination time at the gate. Eat and sleep on the cabin schedule that matches your destination, not your origin.
• Sleep strategically. If it''s night-time at your destination, try to sleep. If it''s daytime, stay awake — read, watch films, walk the aisle.
• Move every couple of hours. Short walks and ankle rotations support circulation on long sectors.
• Go easy on alcohol and caffeine. Both interfere with sleep and add to fluid losses.
• Drink water regularly. A useful guideline used by aviation health resources is around 250 ml of water per hour of flight. Electrolytes (sodium, potassium, magnesium) help the body retain and use that fluid effectively, which is why many frequent flyers add an electrolyte drink to their in-flight routine. TRAVELYTES™ FLIGHT is a low-sugar electrolyte stick designed to be used this way during any flight — it''s a hydration product, not a remedy for jet lag.

When you land

• Get outside. Natural daylight is the single strongest signal for resetting your body clock. Aim for at least 30 minutes of outdoor light at the right time of day for the direction you''ve travelled.
• Eat on local time. Three meals at local breakfast, lunch and dinner times help anchor your rhythm.
• Keep moving. Light exercise — a walk, a swim, a short gym session — helps push back the urge to nap at the wrong hour.
• Limit long daytime naps. If you must nap, keep it to 20–30 minutes before mid-afternoon.
• Stay hydrated. Continue drinking water through the first 24–48 hours after arrival; cabin dehydration doesn''t resolve the moment you step off the aircraft.

Eastward vs westward: which is harder?

Most travellers find eastward flights (for example, London → Singapore, or New York → London) harder. You''re asking your body to fall asleep earlier than its current rhythm allows. Westward travel extends your day, which most people tolerate more easily because staying up later is generally easier than falling asleep earlier.

How long does jet lag last?

It varies by person, age, direction of travel and number of time zones crossed. A common rule of thumb is one day of adjustment per time zone for eastward travel and slightly faster for westward travel. Good light exposure, consistent meal timing and adequate hydration tend to speed the process up; alcohol, irregular sleep and staying indoors slow it down.

What about supplements?

Some travellers use melatonin to support sleep timing when crossing multiple time zones; in the UK it is a prescription medicine, so speak to a pharmacist or GP. Electrolyte drinks and oral rehydration products support hydration but are not treatments for jet lag — claims to the contrary are not permitted under UK ASA and US FTC/FDA advertising standards, and we don''t make them.

The TRAVELYTES™ approach

We make low-sugar electrolyte sticks formulated for travellers. FLIGHT is designed for in-flight hydration. CRUISE is formulated for warm-climate and at-sea travel. MAX adds 80 mg of caffeine for travellers who want a hydration option with an alertness boost on long, early or jet-lagged days. All three are food supplements, not medicines, and are intended to support normal hydration alongside the lifestyle habits described above.

Quick checklist

• Shift sleep 2–3 days early
• Plan light exposure for the direction of travel
• Set your watch to destination time on boarding
• Around 250 ml of water per flight hour, plus electrolytes
• Limit alcohol and caffeine in-flight
• On arrival: daylight, local meal times, light movement, short naps only

Safe travels.