Your jetlag is worse coming back to Australia and there's a scientific reason why.

If you want to support independent women's media, become a Mamamia subscriber. Get an all-access pass to everything we make, including exclusive podcasts, articles, videos and our exercise app, MOVE.

I recently returned from Europe and had the worst jet lag (I know, cue the violins). But it was torture. I could not sleep past 2:30am for the first four nights.

It was nearly to the point of losing sanity from sleep deprivation. It took me a full week to return to a sense of normalcy and being able to sleep.

I wanted to understand: was it just the 'returning to real life' and work doldrums?

Why is it you can get off the plane from Australia when arriving at your holiday destination and seemingly skip into a new time zone so much easier than the way back?

Turns out it's more than just those holiday feels, siestas and sunshine.

Watch: Modern Etiquette: Travel. Post continues below.

What actually is jet lag?

It's essentially a mismatch between your body's internal clock and the local time at your destination. Your circadian rhythm expects daylight and darkness based on where you took off, so when you cross several time zones, that rhythm stays stuck.

So, you might lie awake at night, struggle to wake up in the morning, and even see your appetite and bathroom schedule go completely haywire.

The science behind why coming home hurts more.

And here's the thing: it is generally true that jet lag is worse when returning to Australia, especially from destinations in Europe or the Americas.

The main culprit is the direction of travel. Flying eastward — like when you return to Australia — requires your body clock to adjust to an earlier time zone, which is naturally harder for most people than adjusting to a later one.

Dr Sarah Arachchi, a paediatrician, told Mamamia: "Flying east means you're losing hours, your day shrinks, your body gets really confused, and suddenly you're wide awake at 3am and falling asleep in your lunch at noon," she said.

"It's because your body loves stretching out the day, not shortening it. So flying west (like to Europe) is often easier."

Think about it:

Westward travel (Australia to Europe/Americas): allows you to lengthen your day, which feels more like staying up late, something most of us are pretty good at.

Eastward travel (the dreaded flights home): forces you to advance your body clock, meaning you need to go to sleep and wake up earlier than usual.

Most people's circadian rhythms adapt more easily to staying up later than going to bed earlier. It's like your body is naturally a night owl, even if you're not.

The hormone havoc.

Sandy Milner, a lifestyle physiologist, explained to Mamamia: "The body thrives on biological rhythms and your circadian rhythm is controlled by two hormones: cortisol and melatonin.

"Cortisol is released in the morning and slowly decreases throughout the day, and melatonin peaks in the evening, which is what makes you feel drowsy." she said.

"Their release is influenced by light exposure — sunlight promotes cortisol release and darkness [promotes] melatonin release. Travelling east exposes you to daylight earlier than your body expects, suppressing melatonin and confusing your body's natural rhythm, making it harder to adjust to your new bedtime."

No wonder I was staring at the ceiling at 2:30am and I couldn't get my poor kids out of bed!

How to beat the homeward-bound blues.

Dr Sarah Arachchi has some practical advice that doesn't involve suffering in silence:

Before you even get on the plane:

• Start shifting your bedtime earlier a few days before you leave. Even just 30–60 minutes helps

• Get morning sun if you can and avoid screen time late at night (yes, even that one last scroll)

• Try to wake up early and go to bed early

• Try not to leave your packing until 3am the night before. Your body will thank you

On the flight home:

• Set your phone/watch/life to Aussie time as soon as you board

• Try to sleep when it's night in Australia, even if you're flying over Iceland in broad daylight

• Skip the wine and coffee — both mess with sleep (sorry, I don't make the rules)

• Water. Drink it like your skin depends on it (because it does)

Once you're back in Australia:

• Sunlight in the morning is your BFF. Go for a walk, even if you feel like a zombie

• Avoid long naps. Keep it under 30 minutes if you must

• Eat at normal mealtimes, even if your body is confused. It helps reset your internal clock

• Don't overbook your first few days back

Remember: it may take up to five days to recover from jet lag, so be kind to yourself. Your body isn't being dramatic, it's genuinely confused about what time zone it's supposed to be operating in.

So next time someone tells you jet lag is "all in your head," you can confidently tell them it's actually all in your hormones. And that eastward travel really is the villain in this story.

Feature Image: Supplied.

Dr Sarah Arachchi is a Paediatrician and author of Brown.Female.Doctor. You can hear more from her at @kidsdoctorsarah

You can hear more from Lifestyle Physiologist Sandy Milner at Lifestyle Fizziolology