Anyone's who's travelled non-stop between Sydney and Los Angeles knows what an exhausting, draining, time-zone bending trip it can be.
Lucky for Dr Michael Breus, who endured the notorious flight this week, he is one of the world's leading sleep experts and a pro when it comes to sleeping in transit and combating the dreaded jet lag.
Dr Breus - or The Sleep Doctor as he's known to US television audiences - is in Sydney this week to promote the innovative luxury bed he developed with Princess Cruises, which is being rolled out across the company's fleet.
But before he could get on with the business of spruiking his partnership with the cruise company, the US-based doctor had to acclimatise to a time zone 18 hours ahead of his own.
"I left on Sunday evening from LA and arrived here on Tuesday morning at 6am," he told news.com.au.
"What I did was, I got on the aeroplane at 10.30 at night and made a point of staying up until about 2am - 2am according to my body clock time - and then I slept on the plane.
"I woke up with about half and hour before we landed, and I got up and brushed my teeth, washed my face and had something to eat.
"After I landed I went outside and got plenty of sunshine, which turns off melatonin in the brain (melatonin is a hormone that regulates sleep and wake cycles).
"I left the airport at about 6.30am, I was at [Sydney] harbour by 9am, I worked all day and was in bed by 9.30pm. It was just a matter of really taking a look at my schedule and understanding what I needed to do to sleep."
Dr Breus' expertise in sleep and travel made him a pretty ideal person to help Princess Cruises develop the Princess Luxury Bed, which will be introduced on Australia-based ships the Golden Princess and Sea Princess this month.
The bed is equipped with a bunch of features to make sure passengers at sea get the best sleep possible - even during those rocky patches.
The beds have already been installed on some of Princess Cruises' global fleet and Dr Breus reckons people enjoy them so much, they've become an unusual holiday souvenir.
"We started selling the beds off the ships," he said. "We sold out of all of them in a month. We didn't realise how popular they would be."
As part of his partnership with Princess Cruises, Dr Breus - who is a regular guest on The Dr Oz Show - is also offering information to cruise passengers about getting the best snooze while travelling.
"Sleep is kind of a mystery to most people. We think, I'm going to go into that room and I'll be in there for anything between six and nine hours and hopefully something happens so I'll feel refreshed after it," he said.
"There's still so much for people to learn. And we really don't want people to think they need a vacation from their vacation - the goal is to come back refreshed and come back feeling new."
So how do we get better sleep while we're travelling?
"The biggest thing to worry about is light," Dr Breus said. "When light hits the optic nerve it tells melatonin to stop, and melatonin is the key that starts the engine for sleep, so it's one of the things you want running and gunning when you want to go to sleep.
"Maintaining a high level of darkness, whether it's by using darkout curtains in your room or an eye mask, can help.
"And being cooler makes it easier to fall asleep than being hot."
What you eat and drink before bed can also determine how ready your body is for sleep, he said.
"Think carefully about caffeine, which can affect the body's ability to fall asleep ... so avoid it at night.
"Especially the first night [away], make sure you're hydrated. And watch your sugar. When you ingest a lot of sugar your body has to increase insulin, and that leads to high cortisol levels, and high cortisol levels also affect sleep."
Dr Breus also had some surprising advice for getting the best rest on a flight - even when you're crammed into the cattle class.
"If you're stuck on an aeroplane in economy class, which can be cramped, stay as close to - but not in - the exit row as you can be," he said.
"Sometimes the exit row seats don't lean back and that can be a hassle. But the reason you want to be close to the exit row is because you're closer to the centre of the fuselage and you're going to feel the least amount of turbulence there.
"Get a window seat, and you can roll up a jacket or bring a pillow and prop it up to rest your head. That's the best way: leaning [your seat] back three inches is not going to do a lot for you.
"And one thing I tell my clients is that if you have a [U-shaped] neck pillow, turn it around so the bottom of the U is under your chin.
"That's because your head tends to bob which will wake you up, and by rotating the pillow it stops your head from bobbing.
"Some of my patients also use melatonin, which you can take in supplement form.
Provided you have spoken to a doctor and understand how to use it, it's a perfectly appropriate way to get to sleep."