If that morning alarm clock is getting harder and harder to wake up to every morning, that’s more or less what’s supposed to happen.

It’s one of the quirks of human biology that our daily circadian clock doesn’t operate exactly on a 24-hour cycle. Instead, it’s ten to twenty minutes longer than that.

That’s not the end of the world. But added up, it can make that alarm clock harder to bear.

It also makes it more difficult to emulate all those successful entrepreneurs, like Board of Directors founder Stefan Kazakis and five:am yoghurt founder David Prior, who start their days before 5.30am.

“That’s when we milk our cows, but it is a personal thing for me too — I get up every day at 5am,” Prior says.

Our circadian clock is not the only way our bodies work against us when it comes to being a morning person.

For many of us, we’re genetically predisposed to a lifestyle utterly different from the one we want, says associate professor Dr Sarah Blunden, the head of paediatric sleep research at Central Queensland University.

“The human race is more or less split into those that prefer the night and those that prefer the morning,” she tells SmartCompany.

People’s body clocks, or circadian rhythms – when they feel like they should be awake and when they feel the need to sleep – rarely match up to society’s accepted waking and sleeping times.

“It’s a temperamental and genetic trait. And many of us inadvertently choose jobs that go along with that – night people often choose work in hospitality, for instance.”

But biology is not destiny, at least, not entirely. Many people’s careers require them to work early, and there are strategies you can use to help your body adjust.

Dr Blunden suggests the few following:

Rhythm and rhyme: our bodies adjust to what’s regular

The first step, she says, is to build regularity into your daily routine.

“It’s just basic sleep hygiene,” she says. “Give yourself external cues – like your alarm clock, having breakfast, your morning coffee – to train you to be habitually awake and alert at the same time.

“With habit, we can override that desire to sleep in later. Not that that’s a problem, but it can be if you need to get up early.

“You want to keep that rhythm as habitual as possible. Of course, you can sleep in on weekends. But it’ll make getting back into that rhythm hard. Your body clock will move forward, particularly if it’s predisposed to doing this.”

Use the light to your advantage

Exposure to light is one of the main ways we can guide our circadian rhythm.

Melatonin is a hormone that, in layman’s terms, makes you sleepy. Our brains produce melatonin, but far less quickly when there’s light to our retinas. So, sunlight wakes you up, while in darkness, you feel sleepy.

“If you want to be alert and not sleepy, expose yourself to lots of light,” Blunden says.

“Between 6am and 9am is the best light for this. Open the curtains; have breakfast outside; get out into the air. Walking to work at that time does wonders. Light and exercise is a great way of regulating your rhythm.”

At the same time, you can reduce your exposure to bright light at night. Unfortunately for modern lifestyles, Blunden says the light of things like computer screens, tablets and phones is typically bright enough to inhibit production of melatonin.

“Gadgets confuse your rhythm,” she says. “They mean you won’t get sleepy as quickly as you would otherwise.”

Remember, sleep is not the enemy

The average adult needs between seven and nine hours sleep.

Different people have different sleep needs, and there’s no point in fighting that, Dr Blunden says.

“If Joe Blog sleeps 7.5 hours a night and wakes up shattered, but Joe Smith wakes up after seven hours feeling terrific, does that mean Joe Blog is lazy? Certainly not.

“We need to understand that sleeping is not laziness. It’s a physiological drive. The big bad world might give out badges of honour to people who sleep less and work hard, and that needs to be reassessed.

“While we can all ‘cope’ on less sleep than we need, in the long run, sleep is the foundation of all health. If you’re tired, your mental health and cognitive capacity suffers. You’re not likely to be doing your best.”

This article first appeared in LeadingCompany.