Panda eyes, mile-wide yawns, drinking coffee like water ... we've all endured extreme tiredness. But what effect does it have on the brain and should the sleep-deprived fear health problems down the track? Science reporter and new dad Jamie Morton asked an expert.

A colleague described it as a "yellowish" world, a hazy, day-to-day stumble that perhaps only a triple-shot espresso could relieve.

And that was just being a new dad.

For mums, having a newborn baby means absolute sleepless servitude to a crying, hungry, windy little organic alarm clock.

Dads have the luxury of grabbing a couple of hours' shut-eye each night as their partners are left to become one of the zombies on The Walking Dead.


Over the final trimester, baby veterans urged us to make the most of ordinary things while we could, as if we were somehow facing imminent incarceration or the end of days.

Have a night out and drink liberally, they said. Go to the movies. Travel.

Always, the biggest recommendation was to sleep. "Just sleep, mate. Sleep, sleep, sleep."

And how right they were.

Precious as our little fella is, baby Harry has brought the end of repose as we knew it. Sleep deprivation has become a pitiless way of life.

The Sisyphean task of changing nappies is managed easily enough, but constructing a 300-word article now takes twice the time.

Being almost too exhausted to write this very article about tiredness was painfully ironic.

The creative machinery that had run so smoothly for more than a decade simply appears to have seized up. Mind-blanks and zone-outs strike frequently and without warning. Thoughts trail off into nothingness and focus is elusive.

Finishing a story recently, I filed it with the note to editors: "for print". At least, I thought I had. Someone pointed out I'd instead inexplicably written: "FOR A MAN".

There has been senseless mumbling, a lost wallet, a burnt hand and near-successful attempts at horse-like, upright dozing at 4.15am to the dull hum of the microwave, the bottle's hypnotic circling inside it lulling me back to unconsciousness.

Other things may or may not have actually happened, things I couldn't even begin to explain, and I'm not one for LSD.

Ryan Reynolds nailed it when the Hollywood star told Men's Health: "You want to trip balls? Have a kid and see what it's like to be awake for a month straight.

"You'll have moments where you're like, 'Did I really ride a unicorn to work? I'm pretty sure I didn't, but I don't know."

I haven't yet ridden a unicorn, but I'm clearly among the quarter of Kiwis a recent survey found are tired on a daily basis, and definitely one of the 80 per cent who'd prefer a full night's sleep to a great night out.

When the chance came to attend a training workshop away from home, I jumped at it. Sociable as I am, after-work beers with colleagues I love couldn't compete with resting my head on those gentle white pillows at Rydges Auckland.

To paraphrase an old US Marines saying from the Pacific War: Never stand when you can sit; but never sit when you can lie down.

If we don't sleep enough, the neurochemicals that help us slumber simply keep working the following day.

Curious about what I was experiencing, I phoned sleep researcher Dr Karyn O'Keeffe, of Massey University's Sleep Wake Research Centre.

Nearly everything, it seems, can be clarified by the complex laws of biochemistry.

My opening question was why mind-blanks occur, as just trying to think of one to ask was a difficult feat.

Our brains, she explains, experience a build-up of neurochemicals that slow the firing rate, or activity, of neurons and hence promote sleepiness. When this kicks in, we get periods of blankness, or "micro-sleeps", where we momentarily disengage from the world.

We are programmed to sleep seven to nine hours each night.

If we don't sleep enough, the neurochemicals that help us slumber simply keep working the following day, when we should be riding those that promote wakefulness.

Because I'm running on about six hours' sleep each night, there's inevitably going to be a significant impact on brain performance.

In fact, I'd function better if I normally slept well and one time missed out on sleep entirely for 24 hours than I would if I went through two weeks of this hell. For the record, it has been eight weeks.

As expected, sleep loss makes some jobs harder to do than others. People in creative jobs, for example, find themselves less productive, less able to problem-solve, more fixated on single ideas and struggling to think outside the box.

Others who work in potentially dangerous situations - a construction worker or a truck driver - need to know being tired could cause them to take more risks and make poorer decisions.

Along my drive to work, a big billboard bluntly barks: Sleepy? Pull Over Now.

It's warranted: sleep loss is the most common cause of driver fatigue. In 2014, it accounted for more than 500 crashes on our roads - 31 fatal - and around $268 million in related costs.

Road crash researchers point to people driving long distances without pulling over, and also to workers clocking up too much overtime before climbing into the driver's seat.

Kiwis are famously good at working too hard. More than a quarter of us work more than 40 hours a week and a study last year indicated one in 10 drivers falls asleep at the wheel.

But work, and grizzly bubs like Harry, aren't the sole reasons for being tired. Increasingly, the norms of modern life are eating away at our sleep supplies.

If you watch TV or use a laptop, smartphone or tablet right up to lights-out, you're in good company - more than half of us do it.

Even with my low stocks of shut-eye, I'm still guilty of checking my Twitter feed for that one last time before lunging for the lamp.

This is a huge no-no for sleep seekers because bright light hinders our ability to fall asleep and determines how refreshed we feel when we wake in the morning.

Yes, your smartphone can give you a hangover. Blame shortwave blue light emitted from devices, which is registered by cells behind our eyeballs that tell our brain it's morning. Red lights indicate it's night.

This effectively resets our internal biological clock to an hour later, postponing the release of sleep-promoting hormone melatonin, and we find it tougher to get out of bed when the sun is up.

That said, I've never woken easily. If last year's Rugby World Cup was tough on the English, it wasn't easy on me, either.

So being woken every three hours in the night has been a shock to my biological system.

Our circadian clock - scientists call it a circadian oscillator - hard-wires our bodies to have the strongest drive for sleep from 2-5am.

Added to that an army of biochemicals build in our brain during the day that do their damnedest to make us sleep in the wee hours.

So, when Harry starts bawling at 3am, fighting the urge to roll back over and return to that dream about giant pizza mountains can be the biological equivalent of paddling up a waterfall.

We feel groggy, can't think clearly and have poor motor-function, which is why the odd onesie ends up buttoned back to front. Just as unsurprising, we can't regulate our emotions, leading to those incoherent post-midnight arguments parents are all too familiar with.

Ever see that horror film Paranormal Activity, where a family tries to capture a resident night-time poltergeist on CCTV?

My wife and I keep meaning to do the same thing in the hope we might record some incredible new insult one of us has invented.

But as harrowing as it can be, new parents shouldn't worry about this onslaught of fatigue.

Billions of humans before us have been through it and scientists say there aren't any related long-term major health risks, save for that toe you might drowsily dislocate against the side of the change table.

It's the perpetually sleep-deprived who put themselves in danger of developing such problems as high blood pressure, type 2 diabetes, stroke and heart disease.

Short-term sleep disruption does, however, come with a higher risk of weight gain.

Experimental studies have suggested this is because the hormones that regulate our appetite change, altering our levels of fullness and making us more likely to reach for those heavy, carb-loaded foods that pack on the kilograms.

This is good news for the bakery next to my office, given all the chicken pies it has been selling me.

We feel groggy, can't think clearly and have poor motor-function, which is why the odd onesie ends up buttoned back to front.

As for that other fatigue-buster we turn to - caffeine - O'Keeffe said this should be employed only when needed.

"Caffeine gives you a temporary boost in alertness and it's great because it's in your system really quickly," she says.

"The downside, of course, is that it takes a long time to clear." Straight after that first sip of your morning flat white, its caffeine takes just 45 minutes to pass through 99 per cent of the body membranes through which you absorb it.

On average, caffeine has a half-life (the time it takes for your body to eliminate half the drug) of three to five hours, although effects can last up to 14 hours.

If it's just that one cup of coffee in the morning, there shouldn't be any problem as it's all gone before we go to sleep that night.

But if we drink many during the day to stave off tiredness, we're robbing ourselves of more sleep later.

"Relying on caffeine heavily to get through your day means you're going to impact on sleep," O'Keeffe says.

"You won't have as much deep sleep as you need and of course that will create a vicious cycle where we wake up feeling unrefreshed so reach for another cup of coffee."

A better idea for me would be to take a walk around the block or strike up a conversation with someone in my office pod, although these tricks typically only help alertness for 15-30 minutes.

"Really, the only way to get through the day is to get enough sleep."

If that's not an option, I ask, can I adapt to sleep deprivation?

There is debate among researchers about how this works, but some papers suggest that if you miss out on sleep to moderate levels, the brain adjusts accordingly.

Once it adapts, it stabilises at a low level of cognitive performance, but the "baseline" appears to be a mimimum of six hours' sleep.

"If you are only getting around four or five hours every night, then performance will get worse night after night until you get to the point where you are not functioning well." So, what hope is there for us mums and dads, or those of us working double-shifts?

We do have the option of topping up our sleep in the weekends, or when we can, just like you'd keep paying off a credit card in overdraft.

Experts recommend catching up where possible, but it's most important to get enough sleep in every 24-hour period.

"There's also an issue that if you're sleeping in very small bouts, like several times a day, you don't necessarily get to experience all of the sleep stages that you need."

We've come to understand much more about why sleep is so important to us, but O'Keeffe says there are still big data gaps in New Zealand that urgently need filling.

In an era when we're bringing the office to bed, we need to get a better picture of how our work lives and technology use are conspiring against our sleeping habits.

In the meantime, I take comfort in the fact my extreme tiredness is fleeting, just like one of those big gummy smiles Harry has started treating us to. This world won't last forever.