As a fairly seasoned traveler, I always believed that I was above jet lag.

As long as I wasn’t continually checking the local time of my previous location, or whingeing about what hour of the night my body clock was on, I was fine.

I was flexible. I could time travel like an absolute boss.

Then, I frolicked away to Europe with all the other Aussies in search of some sunshine and an Aperol Spritz.

Like every other trip, it was seamless.

I slipped into my new time zone with the ease of a Swiftie entering the party during a Tay Tay song.

That is, until my wallet was as empty as my cocktail glass and I was trudging to my gate for the flight home to real life.

In a last bid to savor my precious annual leave, I threw caution to the wind and spent my two long flights watching movies, drinking white wine, and sleeping whenever I damn felt like it.

Not once did I check local Australian time to get my body pre-adjusted, or calculate when I should sleep for my 6 a.m. arrival in Sydney on Sunday morning.

And, boy, did I pay for it.

That week, I felt like I was being forced to complete my workday at three o’clock in the morning.

I snuck glances at the local time in Germany where I had just been, to validate my heavy eyelids and feel sorry for myself.

I drank coffee and ate chocolates and couldn’t decide if I was hungry or nauseous.

I left the window open in hopes that the cold air would keep my desk from beckoning me to have a nap on it.

So why was I suddenly a victim of jet lag now, when I had been blissfully ‘above it’ my whole life?

Health and wellness expert Dr Vincent Candrawinata says jet lag is a combination of three things: your circadian rhythm, hydration, and circulation.

Our circadian rhythms, or biological clocks, are disrupted when we fly across time zones, and it matters which direction we’re flying.

“Aussies are actually really lucky in a way,” explains the founder of Renovatio Bioscience, “because majority of the time we fly west, right? We fly back in time, but you’re excited for your trip. So a lot of times you don’t actually feel the jet lag, and while coming back, you’re flying into the future or you’re flying to the later time zone back, into our time zone.”

Dr. Candrawinata says, basically jet lag is generally worse after we Aussies touch down on home soil.

Talk about post-holiday blues.

And all those movies I binge-watched with the care of someone who’s got nothing better to do?

According to the researcher, the blue light emanating from our screens is only worse for our circadian rhythms.

If we want to sleep, we need to ditch the screens for at least 30 minutes beforehand.

The second step to becoming a jet-lagged shell of yourself is to get dehydrated.

“Imagine a bottle of water being squeezed and then expanding, our body is able to cope with that. But obviously, for … people whose body is not hydrated properly, it impacts your brain function, because 70 percent of our brain is water and that perception of time can even be made more sensitive or worse.”

In other words, the white wines I thought would lull me to sleep (which is partly true, as the effect of alcohol is heightened in higher altitudes) were actually dehydrating my brain and setting me up for a week of sloth mode.

And the lack of movement aboard a plane doesn’t help.

“Our body relies on blood circulation that delivers not only nutrients but also oxygen. When people are dehydrated, or not tolerating the cabin pressure very well, obviously that impacts the amount of blood and the quality of oxygenated blood that goes to the brain.”

Two tips Dr. Candrawinata has for jet lag sound almost too simple to be true: eating Vegemite, and brushing your teeth.

The doctor says the Australian staple, coupled with proper hydration, “is packed with the B vitamin, and is also quite salty,” making it the perfect way to replenish your electrolytes.

And, “whether it’s a morning flight or night flight,” the Indonesian-born doctor always brushes his teeth.

“Because it means that you get ready at least an hour before landing, and you get moving, you basically encourage your body and tell your body that come on, it’s time to get active again.”

Dr. Candrawinata also recommends some light exercise and proper hydration after your arrival to kick your body back into gear and avoid letting jet lag turn into something more.

“Because when your body doesn’t get rid of jet lag in the first 48 hours, it then makes the whole system sluggish.”