Jet Lag and Circadian Rhythm Disorder
Most people have experienced jet lag at some point. That groggy, heavy, out-of-sorts feeling after a long flight is a classic example of jet lag and circadian rhythm disorder. Circadian rhythms are your body’s natural 24-hour cycles that guide when you feel awake, sleepy, hungry, and even how your mood shifts. When your internal clock falls out of step with the world around you, like after crossing time zones, your sleep, energy, mood, and even digestion can all take a hit.
What Is Jet Lag?
Jet lag (or jet lag disorder) is a temporary sleep problem that occurs when you travel quickly across time zones. It’s part of a group of conditions called circadian rhythm disorders. Your circadian rhythm is your body’s internal clock, a natural 24-hour cycle that tells you when to feel awake, when to get sleepy, and even influences digestion, hormones, and body temperature. When you suddenly switch time zones, your body clock stays stuck in your original schedule while your new environment runs on a different schedule.
That mismatch leaves you feeling tired when you should be awake, or wide awake when it’s time to sleep. Beyond fatigue, many people also notice mood swings, stomach upset, and difficulty concentrating. While jet lag usually fades after a few days, frequent travellers can experience more lasting disruption that affects their overall health and wellbeing.
Symptoms of Jet Lag
Everyone experiences jet lag a little differently, but some of the most common symptoms include:
- Trouble falling asleep, staying asleep, or waking much earlier than usual
- Feeling sleepy and drained during the day
- Difficulty focusing or performing at your usual level
- Stomach upset (constipation, diarrhoea, or indigestion)
- Irritability or mood changes
- A general sense of being “off” or unwell
These symptoms typically start within a day or two of crossing at least two time zones. They tend to be worse after eastward travel and usually last about one day per time zone crossed.
Why Does Jet Lag Happen?
Jet lag comes down to timing. Your circadian rhythms adjust slowly, roughly one day per time zone, so your body takes time to catch up.
A few key factors can make symptoms better or worse:
- Direction of travel: Flying east (losing hours) is harder to adapt to than flying west (gaining hours).
- Light exposure: Natural light tells your body when to release melatonin, the hormone that helps regulate sleep. Getting the wrong light at the wrong time can confuse your body clock.
- Travel strain: Long flights mean cramped seats, disrupted sleep, dehydration, and irregular meals — all of which add to fatigue.
- Age and frequency: Older adults and frequent flyers often find recovery slower and symptoms stronger.
Managing Jet Lag
The good news is that jet lag is temporary, and you can take steps to soften its impact. Research shows that the right mix of light exposure and timing of sleep can help your body adjust more quickly.
- Plan ahead: Before your trip, start adjusting your sleep schedule by going to bed earlier if travelling east, or later if heading west. Even small shifts help.
- Use light wisely: After eastward travel, seek bright morning light. After westward travel, evening light works best. Cut back on late-night screens that throw off your body clock.
- Hydrate well: Drink plenty of water before, during, and after your flight. Minimise alcohol and caffeine, which worsen dehydration and interfere with sleep.
- Sync with local time: As soon as you land, eat meals, get outside, and schedule activities according to the local clock. Try to avoid long naps, which delay adjustment.
- Sleep smart on the plane: If it’s nighttime at your destination, create a dark, quiet environment with an eye mask, earplugs, or noise-cancelling headphones. If it’s daytime there, do your best to stay awake.
- Consider extra support: Some frequent travellers use melatonin supplements or light therapy. Always check with a healthcare provider before trying these, as timing and dosage are important.
What to Do Next
For most people, jet lag is a temporary nuisance. But if you find your sleep problems are persistent, severe, or not linked only to travel, you may be dealing with a circadian rhythm disorder. In that case:
Most cases of jet lag are temporary and resolve within a few days. But if your sleep difficulties are severe, persistent, or not clearly linked to travel, you may be dealing with a broader sleep disorder.
- Consult a healthcare provider or sleep specialist. They can assess your symptoms, rule out other conditions, and suggest targeted therapies if needed.
- Use practical strategies.Try our 5-Step Sleep Coach Method, which offers easy, evidence-based tools to help you adjust your sleep, manage fatigue, and support your body clock.
- Apply travel tips. Follow the light, schedule, and sleep strategies in the “Easing Jet Lag” section to help your body adapt faster after flights.
With the right mix of preparation, daily habits, and medical advice when needed, you can keep your body clock better aligned and protect your sleep, energy, and wellbeing no matter where you land.(1)(2)
References
- Sack, R.L., Auckley, D., Auger, R.R., Carskadon, M.A., Wright, K.P., Vitiello, M.V. and Zhdanova, I.V., 2007. Circadian rhythm sleep disorders: Part I, basic principles, shift work and jet lag disorders. Sleep, 30(11),1460–1483. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC2082105/
- Lack, L.C. and Wright, H.R., 2007. Jet lag: heuristics and therapeutics. Sleep Medicine Reviews, 11(3), pp.157–167. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6069654/
