Unpacking the Symptoms and Causes of Jet Lag

Jet lag can turn the excitement of travel into a challenging ordeal, disrupting your sleep and leaving you feeling out of sync with your destination’s local time. 2025 is the year of travel for many people, with anticipation for sun, sand, and sea growing every day! Although we all dream of being sun-kissed in long-distance destinations, a long-haul flight rarely comes without jet lag.

Explore the symptoms and causes of jet lag, from insights into why it occurs to how to alleviate its effects. Whether you’re a seasoned traveller or a first-time flyer, understanding jet lag can help you navigate your journey easily and ensure your travel experience is as enjoyable as possible.

Jet lag definition:

A maladjustment of circadian rhythms that results from travelling through several time zones in a short span of time. Rest, work, eating, body temperature, and adrenocortical-secretion cycles may require several days to adjust to local time.

Source: APA dictionary

What is jet lag?

To get technical, jet lag, also known as “time zone change syndrome” or “jet lag disorder” is the name for a temporary sleep disorder caused by travelling across multiple time zones. Generally, it occurs when travelling across three or more time zones.

Travelling can take a toll on your body, especially regarding sleep. Many of us have experienced the symptoms of jet lag, which occurs when your body is still in your home time zone. This means you find it difficult to sleep and wake with the local time. This can leave you feeling exhausted, frustrated, and struggling to sleep properly when you arrive at your destination or return home.

What are the symptoms of jet lag?

While the severity and the number of symptoms suffered differ depending on the person, the number of time zones crossed and even the direction of travel, they include:

Insomnia
Nausea
Confusion
Anxiety
Fatigue
Headaches
Gastrointestinal issues
Irritability

Check out the NHS guide for more information on symptoms, and speak to a doctor if any of these symptoms remain or become unmanageable.

What causes jet lag?

According to the NHS, jet lag is a range of symptoms experienced while adapting to a different light-dark schedule following a flight to a new time zone.

There are 24 different time zones in the world, and once you cross them, your body’s 24-hour clock is disrupted. This confuses your daily circadian rhythms, such as sleeping and waking, appetite, and even bowel habits.

Plane travel worsens jet lag symptoms, which can include insomnia, daytime drowsiness, difficulty concentrating, and mood swings. Such symptoms usually occur for the first day or two after travel.

Other causes may include:

Long periods of sitting on a plane.
Lack of oxygen and decreased air pressure in the aeroplane cabin.
Warm cabin temperature and low humidity cause dehydration.

How to treat jet lag

To tackle jet lag right after your flight, try soaking up some natural sunlight to help your body adjust to the new time zone. It’s also a good idea to skip the alcohol and caffeine for now—just stick with water to stay hydrated.

While jet lag can’t be completely cured, managing it effectively is possible with the right strategies and a bit of planning. We contacted Dr Tom Paulson from the ParalympicsGB group to gain some expert insights. He shared his tips on how high-level athletes prepare for significant time zone changes. Dr Tom advises that light exposure is one of the primary elements in managing jet lag. He says:

The cause of jet lag is this mismatch between your internal body clock and how your body is physiologically working, with the cues in the environment. Exposure to light has a huge impact on sleep patterns.
When we’re travelling over to Tokyo, you have to advance your body clock, so looking for exposure in the afternoon. This is because when it’s the afternoon in Tokyo, the athletes would usually be asleep at home.
It’s quite difficult to do, but we advise that they start to progress their body clock towards Tokyo time, to knock any jet lag on the head.

These little tips are great for the everyday traveller, but just to be safe, here’s some more advice to keep in mind ahead of your travels.

Dr Pixie McKenna and her guests discuss how to make the most of your sleep when travelling abroad. Pixie is joined by travel expert Simon Calder, who has been writing about travel for over 25 years, as well as Dr Richard Dawood, who has practised as a travel health expert for the last 35 years.

Listen here:

Spotify

While each of these treatments in isolation is thought to offer some reduction in the duration of jet lag, the best solution is likely to be a mixture of several. One meta-analysis of jet lag studies concludes the following:

Long-haul flights over several time zones cause both travel fatigue and jet lag. The most obvious consequences of jet lag are poor sleep at night, excessive sleepiness during the day, and poor mental and physical performance. These consequences occur because the human circadian system cannot immediately adapt to time cues in a new time zone. This manuscript has presented recommendations on how to minimise jet lag using judiciously timed light exposure/avoidance and ingestion of melatonin to help adapt your circadian system to a new time zone.

Jet lag can vary significantly depending on how far you travel and in which direction, so being mindful of it and planning are your best defences against that groggy feeling upon arrival. These tricks should help you prepare for your journey abroad.

However, don’t worry if everything doesn’t go as planned. Even top athletes, like Paralympic cyclist Lora Fachie, face their challenges with sleep. She shared:

Sleep for me has always been a struggle, I can only sleep in 3–4-hour blocks. Now, I’m in a good routine, but I’m concerned about going to Tokyo, as I don’t cope well with clock changes. In 2011, I went to Australia for a World Cup, and I was climbing the walls ready to ride my bike at 2 am!

So, if jet lag gets the better of you, don’t stress. Read up in advance, do your best, and make adjustments to your schedule as needed. Remember, you’re travelling to relax and enjoy life, so make the most of it no matter what!