How to ‘re-sync’ the body after changing time zones

Seasonal Health 19 September 2018

Jet lag and time differences can cause our bodies a lot of stress. Along with sleep problems, insomnia or drowsiness during the day, a time difference of six hours or more can cause a whole variety of annoyances including increased lack of awareness and concentration, lack of motivation, nervousness, grumpiness…

Of course, these all ensure that going back to work is only made even more difficult…

What causes jet lag? 

As the time zone changes, our hormonal cycle continues to function according to the biological rhythm of the original time zone. 

The production of neurotransmitters, cortisol and thyroid hormones all take several days to ‘re-sync’ after we arrive in the new time zone. This has been demonstrated by a temperature curve analysis: 

The sleep/wake cycle, or the body’s circadian rhythm, normally rebalances within two days for a six hour time difference. However, body temperature, stuck on our usual 24h rhythm, can take up to a week to adapt. Other hormones can take between two to three weeks to readjust. 

So it’s no surprise that we can feel a bit out of sync!


Adapting your sleep and diet before your return journey…

A few days before your return, there are several things you can do to prepare yourself for the change back to another time zone.  

Start by going to sleep a few hours earlier/later depending on your time zone: 

– If returning from the Americas, go to sleep earlier and also wake up a little earlierin the mornings. In other words, opt for early morning excursions and avoid late nights out…!

– On the other hand, when returning from Asia, try to go to sleep later and also wake up a little later. 

In any case, avoid accumulating missed hours of sleep and as far as diet is concerned, try to eat immediately before departure and not during the flight to avoid the poor quality meals that can sometimes be served on board. 


During the flight 

If your flight is during the day, try to rest and sleep only for a few hours. However if your flight is during the night, try to sleep throughout and remember to bring ear plugs and a sleep mask! 

 Tip for regular flyers: set your watch on the arrival time zone as soon as you leave! 

Avoid eating in-flight – this is fairly easy to do if you have a healthy and balanced meal before departure. Of course, avoid all alcohol consumption which can cause a false sense of drowsiness and relaxation, majorly disrupting quality of sleep. 

Lastly, think about doing some yoga breathing exercises or cardiac coherence to help with relaxation. 


After your return 

Ideally, try to return 48 hours before starting work again – this makes it easier for you to ‘re-sync’ at your own pace and will allow for any jet lag related mishaps…!

Returning from Asia

Try going to sleep as late as possible to avoid getting up too early the next day. If, despite all effort, you do end up waking up before dawn, avoid doing any intense exercise which might use up all of your initial energy and avoid any strong, bright morning sunlight! 

If going out, wear sunglasses which can then be removed in the afternoon to help your circadian rhythm to adapt. 

A quick 5-20 minute nap can also help you to recover if you do get up too early!

Returning from the West (USA, Antilles, South America)

In this case, you can make the most of early morning sunlight and plan an early run or brisk walk to boost your energy and readjust to your original timezone. 

A breakfast high in protein will enable you to create more dopamine and noradrenaline, the two neurotransmitters responsible for awareness and ability to cope with everyday social and professional events.

If you start to feel tired in the afternoon, take a quick 15-minute nap. 

At the end of the day, avoid bright lights and physical activity to encourage your body to relax. Falling asleep can be aided with supplements including tryptophan, a natural precursor for serotonin and melatonin, the two ‘letting go’ hormones. 


Magnesium and adaptogen plants to ensure a quick return to normal

Magnesium and adaptogen plants (Eleutherococcus senticosus, Rhodiola rosea) enable the body to naturally regulate its production of neurotransmitters and stress hormones. 

Passionflower also acts as a slight sedative for sleep problems caused by summer time zone changes. 



Docteur Sylvie Royant-Parola Comment retrouver le sommeil par soi-même, éditions Odile Jacob, collection poche, 2008 et Les mécanismes du sommeil, éditions Le Pommier, 2013