In April 1970, Frank Cole was driving home from a party to his parents' home in Melbourne when he began to feel drowsy.

In the chilly early hours of Sunday morning, the 21-year-old had on the heater in his EJ Holden and was following his cousin's car.

But after a week working on a sheep farm he was exhausted, and soon felt his eyelids getting heavy.

"I felt myself drifting off, then the next thing I knew I had wrapped my car around a power pole," Mr Cole said.

He was later to learn he had broken his neck and jaw, and would need to spend months in hospital before he was well.

It is a stark reminder of the dangers of sleep deprivation, a condition that nearly cost Mr Cole his life, and which is becoming more common in the developed world.

The Chernobyl nuclear disaster of 1986 and the Exxon Valdez oil spill in 1989 have both been linked to sleepy workers.

"It is quite likely that sleep is serving an absolutely fundamental process," said Dr Amy Jordan, a sleep expert and senior lecturer at the University of Melbourne's psychology department.

"If you take rats and sleep deprive them continuously, they will die after about 20 days.

"It is not like they all die from heart attacks ... They actually die from complex and various reasons."

And yet people continue to ignore their body's needs.

Soaring rates of sleep disorders in Australia

Everyone knows they feel better after a good night's sleep, but new research is starting to unlock the secrets of how, with evidence that sleep affects the body in ways that were completely unimaginable just a decade ago.

Scientists are starting to figure out how sleeplessness impacts on cancer, Alzheimer's disease, obesity and poor school results, among other things.

It is alarming stuff, particularly when you look at the skyrocketing rates of sleep disorders diagnosed in Australia.

The latest figures available from the Australian Institute of Health and Welfare show that in 1998–99 there were about 26,000 people who left hospital after being admitted principally because of a diagnosis of a sleep disorder.

Since then the number has risen each year, to be almost 75,000 in 2012–13, the most recent year for which figures exist.

The number of people with sleep disorders in Australia has risen sharply since 1998. ( Graph based on figures from Australian Institute of Health and Welfare. )

Every mammal, reptile and bird on earth dozes off at some point, but scientists are only just beginning to understand the importance of sleep, and what our disregard for normal sleep patterns is doing to our health.

A restful sleep may be just as important as stopping smoking when it comes to improving health.

Sleep deprivation can be expensive, too.

A Deloitte Access Economics study in 2010 found it was costing Australia an estimated $36.4 billion each year, although it said the figure could be much higher.

Melinda Jackson, a senior research fellow at RMIT University's Health Sciences school, has investigated sleep's effect on the body.

She said despite a commonly held belief that people could easily catch up on a string of late nights by having a long sleep on weekends, it may actually be much harder to regain normal functioning once we have become sleep deprived.

"Fantastic data has just come out, laboratory data, that has shown that after a week of sleep restriction it might actually take five nights of 12 hours' time in bed for someone's performance to come back to their baseline level," Dr Jackson said.

It is a common myth that people who deal with sleep deprivation on a regular basis become immune to the impact of sleep loss or learn to cope with it.

"We actually published a paper last year at the Austin Hospital comparing truck drivers to non-professional drivers. We looked at their responses to sleep deprivation, and the truck drivers were just as susceptible to the effects of sleep loss as non-professional drivers," Dr Jackson said.

The 24-hour work cycle of modern society and the ubiquitous forms of brain stimulants such as smart phones, tablets and TVs are causing people to drift from the in-built circadian rhythm that our bodies have been created to work within over many thousands of years.

So how does this affect people?

1. Road trauma

Sleep deprivation is linked to road deaths.

Superintendent Bob Rennie from NT Police said someone who was awake for 24 hours had the equivalent of a blood alcohol reading of 0.05 per cent, a level that would be illegal in Australia.

"I have put people into body bags who have fallen asleep behind the wheel," he said.

Fatigue was blamed for this car crash that killed a father and his two sons near Cultana in South Australia. ( ABC News )

Figures from the NT Government show more than 10 per cent of motor vehicle deaths in 2014 had fatigue as a factor.

In Western Australia the Office of Road Safety puts the figure in that state at 30 per cent.

2. Alzheimer's disease

One of the most startling discoveries in recent years is the role sleep plays in preventing dementia.

Plaques on people's brains associated with Alzheimer's disease may be linked to lack of sleep. ( ABC News )

For years it was known that people with symptoms of Alzheimer's commonly had sleep problems, but studies have now shown a link between sleep loss and brain plaques, a hallmark of the disease.

A 2013 study showed evidence that the connection between the two factors goes in both directions, with Alzheimer's plaques disrupting sleep, and lack of sleep promoting the plaques.

"When we looked specifically at the worst sleepers, those with a sleep efficiency lower than 75 per cent, they were more than five times more likely to have preclinical Alzheimer's disease than good sleepers," said Assistant Professor Yo-El Ju on a Washington University blog.

Australia's population is ageing, with more than 50 per cent of people in a study of 12,000 reporting they regularly felt tired.

3. Cancer

Dr Jordan from the University of Melbourne said work in the United States showed that cancer cells injected into rats spread far more quickly if the animals were sleep deprived.

"Certainly if you have cancer and you have on top of that sleep deprivation, then the cancer gets worse quicker and progresses further into the bone," Dr Jordan said.

"I believe the mortality was higher in the animals that were sleep deprived as well, so they died from their cancer sooner," she said.

Dr Jordan said a large study also showed that health problems were more common in nurses who did shift work than in nurses who worked only in the daytime.

"[The nurses on irregular shifts] have higher rates of cardiovascular disease, they tend to be more overweight, and they have higher rates of cancer," Dr Jordan said.

As well as having more cancer, sleep deprived people are less able to cope with the pain of some cancer treatments.

"If you have disrupted sleep or you are sleep deprived then you will find a noxious stimulus more painful than if you were well rested," Dr Jordan said.

"A lot of cancer patients have issues with pain, so a good night's sleep would also help in that regard."

4. Anxiety and Depression

Links between sleep disorders and depression have been well documented in numerous studies but as more data trickles in the full extent of the relationship is becoming clearer.

In 2005, a study published in the journal Sleep found people with insomnia were nearly 10 times more likely to have clinically significant depression than others.

The same study showed insomniacs were also more than 17 times more likely to suffer from anxiety.

"These results reaffirm the close relationship of insomnia, depression, and anxiety, after rigorously controlling for other potential explanations for the relationship," the study concluded.

5. Obesity

Dr Jordan said people deprived of sleep, or who had disrupted sleep, experienced changes in blood glucose levels that could predispose them to adult-onset diabetes.

People who are tired eat more than those who are well rested.

"There are changes in how much you eat, so people who have had four nights of just getting four hours of sleep a night, if you give them a free buffet, they will consume on average about 500 calories more than someone who is well rested," she said.

It is also thought that sleep-deprived people could be too tired to exercise, or be awake for longer, giving them more opportunities to eat.

A US government-funded study found the growth in obesity had accompanied a parallel growth in chronic sleep deprivation.

6. Academic results

Again in the US, a study looking at more than 43,000 students found the impact of sleep deprivation had as big a role in academic performance as binge drinking and marijuana use.

Psychiatry professor Mary Carskadon from America's Brown University told the ABC that good sleep enhanced learning gains that students had made the day before.

"Sleep prepares people for learning by enhancing alertness, attentiveness, motivation, and decreasing irritability, distractibility, and moodiness," Professor Carskadon said.

She said there was evidence that with certain types of learning, students who slept well were rewarded with a roughly 15 per cent gain in examination results compared with those students who did not.

"We think that most teens will do well with about 8.5 hours of sleep every night on a routine schedule. For optimal results, some teens may need a bit more sleep," she said.

Despite those findings, Australian parents seem uninterested in changing school times or letting children forgo early morning sports training in favour of more sleep, said the executive director of the Australian Parents Council, Ian Dalton.

"I think there is a general acceptance in Australia that body clocks are something that can be trained," Mr Dalton said.