Tony Wright was tired, and with good reason. He'd been awake for 11 days, two hours -- a world record.
"I tend to feel better in my body when I've been awake 4, 5, 6 days," he said.
Wright, a 43-year-old gardener from Cornwall, England, thinks sleep deprivation might open a world of enhanced brain function. Most sleep researchers strongly disagree.
Try sailing round the world on your own, and you'll suffer from sleep deprivation.
"I was so tired," said Ellen MacArthur, who broke the world record for the fastest solo circumnavigation of the globe in 2005. "Oh, God, it was just too much."
Doctors also suffer from sleep deprivation. "I was so tired I prescribed 20 times the right dose," one doctor said.
In our own very small way, even journalists suffer. Covering the tsunami, the combination of what we witnessed and a heavy workload kept us awake for days. This reporter looked and sounded drunk while doing a live shot from Banda Aceh.
"Researchers have compared the effects of alcohol intoxication to the effects of sleep deprivation," said professor Derk-Jan Dijk of the University of Surrey's Sleep Research Center.
But when you get right down to it, we don't know exactly how or why sleep revives us. What we can spend nearly one third of our lives doing, we know very little about.
"Sleep has been ignored by part of the scientific community and part of the medical community," said Dijk. "It's so much easier to study wakefulness."
At the University of Surrey's Sleep Research Center, they're trying to make up for lost time by analyzing the brain waves of sleeping volunteers like me.
They wired me up one morning at the center. I thought I'd had a good night's sleep and I drank four cups of coffee with breakfast, but within minutes, I fell asleep. Like many people, I'm sleep deprived without even knowing it. And sleep deprivation has a profound effect on how you function.
"You will find it very difficult to concentrate," said Dijk. "You will find it difficult to pay attention. You might find it difficult to speak and to construct sentences that make sense. Logical reasoning will certainly be affected."
Researchers at the university test brain function with psychometric tasks, such as identifying colors. They've discovered that a gene called "period 3" might be crucial. People with a short version of the gene did well picking yellow or green in the early hours. But 10 percent of humans have a long version: They struggled with the test and even struggled to stay awake.
After just 24 hours without sleep, everyone suffered mental impairment equivalent to being too drunk to drive a car, and researchers thought it unethical to push their human guinea pigs any further.
"It's clear that in animals sleep deprivation will ultimately lead to death," said Dijk. "If you keep rats awake for several weeks they will die."
Die of what?
"That is something that is not entirely clear," said Dijk.
Tony Wright has pushed it as far as any human we know of; he thinks his secret might be the raw food diet he's followed for 16 years.
"It was 1995," Wright recalled. "I decided I'd stay awake and see what happens."
At his first attempt Tony managed a weekend, 80 hours.
"I mostly felt very relaxed and a kind of mild feel-good factor, which is a surprise for most people because their experience of staying awake is of trauma and desperation," he said.
This summer, in a bar in England, he lasted 11 days.
"From about day five to about day nine, I was playing a lot of pool during the small hours," he said.
There were peaks and troughs, though. He says the "last couple of days" were very difficult, and when he passed the previous record, he said he lost focus and closed his eyes.
"It was somewhere between 5-and-a-half and 6 hours and that was it," he said. "I woke up and it was back to normal for me." But Wright believes what's normal for him isn't what's normal for everyone else.
"I don't know if I've felt totally normal for a long time," he said.
Wright's theory that sleep deprivation might bring a higher state of brain function is strongly disputed.
"In the brain we will see that the brain waves will become slower and slower as if the brain doesn't function optimally anymore," said Dijk.
Eventually we will shut down. We will fall asleep before we die like a lab rat -- but that can also be fatal. Last month a woman in Colorado drove 30 miles at speeds of up to 70 mph. All while dipping in and out of sleep. A fellow driver on the highway, Christian Pruitt, caught the SUV on his video camera.
"I turned on my video camera as we pulled alongside her. She nearly clipped us in our lane. She was asleep," he said.
Amazingly no one was killed. Dozy drivers cause 100,000 accidents a year in the United States, which result in 1,500 fatalities. And most sleepy drivers are young.
The Simple Solution
"And this is because -- and this may surprise you -- it's much easier to keep an older person awake during the night than it is to keep a young person awake during the night," said Dijk. "Because the older probably needs less sleep."
Older people do seem to require less sleep, but doctors don't know why.
"If we knew that we'd probably know more about the function of sleep," said Dijk. "Undoubtedly [it] has to do with changes in the brain that occur as we grow older. But what those changes are and what the function of those changes are, is unclear."
Caffeine and other stimulants can lengthen the attention span of an underprepared student the night before a big test, but they don't solve the problem.
"Here still, is that need of recovery," said Dijk. "It's not that by drinking coffee you can completely remove the need for sleep. Of course there may be an ideal drug to develop."
The U.S. military is trying to develop ways of keeping sleepy soldiers alert without using stimulants, in part by trying to figure out how migratory birds remain aware of predators on long flights. Apparently birds have a natural resistance to the ravages of sleep deprivation.
The military discovered that some parts of the human brain are more resistant to the ravages of sleep deprivation than others. Could soldiers be trained to use those parts of the brain? They say chocolate and leafy green vegetables might also help with alertness.
But Dijk has a much simpler solution for how to stay alert: Get enough sleep.
"Going to bed is always a wonderful solution and it's a wonderful countermeasure," he said.
So, how can you get that good night's sleep? The researchers suggest keeping your bedroom at the correct temperature -- in the sleep labs it's 59.9 degrees. A little chilly for me, and personal preference plays a part here. Also, your room must be dark.
"Most importantly," said Dijk, "you need to take the time for sleep. If your sleep is interrupted very frequently you will feel still very tired in the morning. For sleep to be restorative it has to be deep and it has to be continuous."
We might not know much more than that about sleep. But one thing is for certain, very few of us enjoy being woken up.