Sleepless in battle

Soldiers that have no need of sleep have long been
the dream of military tacticians

The team of crack US Army snipers were close to exhaustion as they trekked across Iraq’s notorious Triangle of Death south of Baghdad. With daytime temperatures pushing 50°C, they had been forced to march through the night, grabbing fitful sleep whenever they could. Then one morning in May last year, what they had dreaded finally happened. Two Iraqi civilians blundered across the hide in which they were trying to get some sleep.

What happened next became the focus of a court martial earlier this year – and a conviction for murder. The jury heard that Sergeant Evan Vela had been ordered to kill one of the Iraqi civilians – and did so without a second thought. Yet Sgt Vela told the court that he couldn’t recall pulling the trigger or even hearing the shot. He was, he insisted, suffering the effects of extreme sleep deprivation – the result of having less than five hours’ sleep in the previous 72 hours.

Medical experts testified that such extreme lack of sleep could have led him to act like an automaton, unable to exercise any moral judgement. And the court appeared to agree. Vela was found guilty of murder, but received a sentence of ten years, rather than the maximum of life imprisonment without parole.

Fighting fatigue

The Vela case is hardly unique. For as long as wars have been fought, soldiers have had to battle with sleep deprivation and have sometimes lost, with terrible consequences. Nor are those in the armed forces alone in their struggle against fatigue: millions of ordinary people suffer from its effects as well, struggling to stay effective at work, or awake while driving. Research suggests that up to 20 per cent of all accidents on motorways are fatigue-related.

Now there’s growing excitement about a new generation of compounds that seem able to keep drowsiness at bay for days on end, with minimal side effects. Known as eugeroics – from the Greek for ‘beneficial arousers’ – they seem to offer the prospect of a whole new way of living, ridding ourselves of the need to spend around 20 to 30 per cent of every day asleep.

But there’s also growing concern about whether there may be a price to pay for interfering with a process every known organism appears to undergo naturally. “Saying we sleep just to stop feeling tired is like saying we need to eat just to stop feeling hungry,” says Professor Jim Horne, director of the Sleep Research Centre at Loughborough University.

Chemical solutions

For anyone needing to keep awake for just a few hours longer than normal, there’s a natural stimulant that according to some anthropologists may even have been used by Stone Age humans: caffeine. Found in dozens of plants and first isolated by chemists around 200 years ago, caffeine boosts brain activity and improves mental and physical performance. Research has shown it’s especially effective when taken just before a brief nap of around 15 minutes (see ‘Beat your body clock’, on p69). But it also produces a host of side effects, from ‘the shakes’ to the heart palpitations that put former PM Tony Blair in hospital in 2003.

Around 70 years ago, scientists synthesised what appeared to be a better remedy, known as dextroamphetamine, or dexedrine. First used during World War II, it appeared to have fewer side effects. Yet by the 1960s, a darker side was seen. Regular users needed ever-higher doses to achieve the same effects, while those who tried to give up the drug ran into a host of problems, from disturbed sleep to violent outbursts.

Banned from non-prescription use in 1970, dexedrine still found uses in special circumstances – the crew of the abortive Apollo 13 lunar landing mission of 1970 were ordered to take the drug by NASA officials after one of the sleep-deprived astronauts made a near-fatal error programming the onboard computer. It is still used by some military personnel.

Yet concern about the potentially deadly side effects of dexedrine remain. In April 2002 an American F-16 pilot accidentally bombed Canadian troops in Afghanistan, killing four. At the subsequent inquiry, defence lawyers claimed the pilot’s judgement had been impaired by taking dexedrine.

Soldiering on

The 21st-century battleground has pushed the search for safe but effective solutions to sleep deprivation up the research agenda. “Typical operational scenarios might include lack of sleep for 24 to 36 hours, or short sleep – four hours a night – for several days,” says Jan Walker of the US Defense Advanced Research Projects Agency (DARPA), Virginia. “Sleep deprivation interferes with the ability to do higher-order mental processing, such as complex problem solving.”

In the late 1970s, French scientists appeared to have discovered the perfect solution: modafinil. Originally developed to treat medical conditions in which patients suddenly fall asleep, modafinil boosts performance for hours on end, while not interfering with the ability to sleep. Tests revealed that troops given modafinil could perform effectively for 40 hours at a stretch – and then get a normal night’s sleep without the sleeping pills often needed after taking dexedrine, before taking more modafinil to keep going for another 40 hours.

Such results have impressed military commanders. Soldiers in the French Foreign Legion were given modafinil during the first Gulf War in 1991, while the US Air Force approved modafinil for use among some of its pilots in 2003. Britain’s Ministry of Defence has confirmed that it has been studying the drug’s effects since the late 1990s – though it has yet to approve its use.

The MoD’s more cautious attitude towards modafinil may prove well-placed. Quite how modafinil staves off the need for sleep is far from clear, and side effects ranging from nausea to anxiety and over-confidence have emerged in studies. Such findings cast a shadow over the vision of a sleep-free society, in which we all take drugs like modafinil to add years of productive activity to our lives. The long-term health effects of such drugs aren’t clear, and some people may be at high risk from side effects. Researchers at Vanderbilt University, Nashville, have found that modafinil raises heart rate and blood pressure, prompting them to warn about the potential risk to patients with cardiovascular disease.

Researchers are studying alternatives to modafinil, such as orexin and ampakines. While both appear to reduce the need for sleep in animals, studies in humans have so far proved disappointing – and their long-term effects are also unknown.

But there is another, more fundamental concern about attempts to create drugs for a sleep-free society. Even if the drugs themselves prove harmless, doing without sleep seems to be anything but.

Tiredness kills! 

While scientists admit they still don’t know the real purpose of sleep, they point to evidence linking disrupted and inadequate sleep to life-threatening conditions. Last December, the International Agency for Research on Cancer warned that women involved in shift working face a significantly higher risk of breast cancer. “Sleep loss – even just an hour a day – is associated with metabolic effects such as impaired glucose tolerance,” says Dr Adrian Williams, director of the Sleep Disorders Centre at St Thomas’ Hospital, London. “We shouldn’t think about reducing the sleep we get until we better understand these issues.”

His concerns are underscored by a recent major study of the impact of sleep loss on heart disease. Published in September 2007 by a team of researchers from the University of Warwick and University College London, the study examined the effects of changes in the sleeping patterns of over 10,000 civil servants.

The results showed that those who had cut their sleep from seven hours per night to five hours or less faced as much as a 70 per cent increased risk of premature death – and a doubling in the risk of dying from cardiovascular disease. Researchers suspect the explanation for the dramatic increase lies in the effect of the lack of sleep on risk factors for heart disease such as high blood pressure. But precisely what happens during sleep to keep the body healthy remains a mystery.

According to the study, a regular routine of sleeping for around seven hours a night is necessary to stay in peak condition. “Sleep represents the daily process of physiological restitution and recovery, and lack of sleep has far-reaching effects,” says Professor Francesco Cappuccio of the University of Warwick.

It seems that, however much we may want to get more out of our lives by cutting back on sleep, most experts agree that doing so may come at far too high a price. “The idea of the sleep-free society is pretty foolish,” says Prof Horne. “If sleeping each day is the only chance we get to unwind, then we should take more sleep, not less.”

Robert Matthews is Visiting Reader in Science at Aston University

Beat your body clock

How to control your body clock – instead of it controlling you
Many of us occasionally have to find ways of staving off sleep, whether it’s while night-driving for a few hours, or when trying to adjust to a new time zone or night-shift working pattern. And the techniques for success vary according to just how long you need to keep awake.

Staying awake for days on end is never advisable, because of its negative impact on mental performance. But if you’re looking to stay awake for a few more hours than usual, research by Professor Jim Horne at Loughborough University suggests that a combination of caffeine followed soon after by a quick nap works best.

It’s important to take the right amount of caffeine and sleep, and in the right order: around 150mg of caffeine – roughly one can of stimulant drink, or two coffees – should be taken first. This takes around 30 minutes to kick in, so the drinks should be immediately followed by a quick nap of about 15 minutes. The combination proved very effective at warding off sleep during night-driving in the Loughborough study.

Shift yourself
When you’re adjusting to a new time zone or shift-work, beating the body clock is less simple. If the time zone is behind the UK – such as the US – it’s best to keep going until as close to local bed-time as possible, using caffeine and bright lights to stave off doziness.

Time zones ahead of the UK – such as Asia – are a bigger challenge. Again, the best advice is to use caffeine and bright lights to stay awake until local bed-time, with another dose to fight off the feeling of being awoken too early the following day.
In either case, it can take up to a week for your body to become acclimatised to the new time zone.

Adjusting your body clock to suit night-working is hardest of all, taking around ten full nights to achieve. The best technique is to have 10-minute breaks every two hours, plus a couple of 15-minute naps – if management allows it.

Q&A with Dr Tom McLellan

Defence Research and Development Canada

What’s the focus of your research?
For the military, recent deployments involve sustained periods where personnel do not receive adequate sleep. As a result, both physical and cognitive function degrades and mission effectiveness is also reduced.

What’s been the biggest surprise in your research?
The extent of the cognitive impairment during an overnight period of sleep deprivation. We constructed vigilance tasks that required our participants to observe infrequent activities – one activity lasting 4-5 seconds every 15-20 minutes over a 90- to 120-minute period. Participants recorded what happened. The degradation in performance was quite astonishing: if their control score was about 80-85 per cent, their scores during the overnight period were reduced to about 40 per cent.

What are the other benefits of your research?
The greatest benefit would be in the transportation industry – ensuring that physical and cognitive function is optimal at a time when it would be compromised. So for truckers driving for long hours or for anyone driving late at night when they are not as alert as they should be, the use of this research could help reduce road accidents.

What questions would you most like to solve?
How long could we continue to maintain physical and cognitive performance with the use of caffeine during the night, and the use of restricted sleep periods during the day? I also would like to know if there is a penalty associated with the use of the drug for prolonged periods. How long will it take to recover so that the sleep cycle can begin again?

Find Out More

• Sleepfaring by Professor Jim Horne (Oxford, 2006)
• Loughborough Sleep Research Centre www.lboro.ac.uk/departments/hu/groups/sleep
• Sleep Council home page www.sleepcouncil.com
• The Journal of Sleep Research www.blackwell-synergy.com/loi/jsr