CAFFEINE NAP – HOW COFFEE PREVENTS DEATH WHILE DRIVING

CAFFEINE NAP – HOW COFFEE PREVENTS DEATH WHILE DRIVING

One of the major causes of deaths worldwide is road accidents and sleeping while driving is the most dangerous thing which can happen and I personally have suffered a loss of very close one due to the negligence of the driver who slept on the wheels at a very high speed. Constant yawning, tired and sore eyes, loss of focus in the vision, drooping head, slow reactions etc. are some of the symptoms which indicate a lack of sleep and over tiredness which if ignored can lead to dangerous consequences and in many cases loss of life.

Lot of people try to wave off this fatigue by singing, eating and listening to music but believe me this only helps for a very short period. Most people deny falling asleep in case they meet with an accident due to the same reason. But you don’t sleep, just a wink for only 2-4 sec can prove to be fatal. A car speeding up at 85kmph covers over 30m in app. 4sec which is equivalent to the size of a tennis court. This much time is enough for a mishap to take place.

In 1996, sleep researchers from the Loughborough University in Britain (L. Reyner & J. Horne), did tests on drivers who were fatigued and the methods which they can successfully use to stay awake. The fatigued and sleepy drivers were put in the driving simulators. The methods to stay awake included rolling down windows to get cold air exposure, slapping oneself on the face etc.

However, the most successful method they found was something called the Caffeine Nap. This means you take a cup of coffee and immediately take a nap for fifteen minutes. Caffeine acts as an adenosine receptor antagonist. It is the molecule which makes us sleepy. Adenosine accumulates in the brain during the time we are awake and it inhibits the functioning of those cells in the brain which helps us stay awake.

Also, caffeine will take around 40-60 min to get into the blood stream and show effect, so an immediate nap after a cup of coffee will make you ready to roll again as it will clear the accumulated adenosine from the brain and at the same time caffeine will block the adenosine receptors in the brain, giving you a double whammy.

Driver accidents are a serious issue for any nation, and sleeping while driving is a well controllable variable. A 2000 study in the journal Psychophysiology, Reyner & Horne, found that, sleep-related vehicle accidents are prevalent early morning, especially in younger drivers. For the purpose of study, following a night of either restricted or nil sleep, young experienced drivers drove for 2hr (0600–0800h) continuously in an immobile car on an interactive, computer-generated, dull, and monotonous roadway. This exercise followed ingestion (at 0530h) of 200mg caffeine (2–3 cups coffee) versus placebo. The study saw that, this caffeine dose, feasibly taken via coffee, effectively reduces early morning driver sleepiness for about 30 min following nil sleep, and for around 2 hr after sleep restriction.

To test this issue further, Reyner & Horne tested the effects of caffeinated energy drinks and their effects on sleeplessness, especially during driving. The study was done in 2002, published in the journal Physiology and Behaviour. For the purpose of the study, 12 healthy young adults drove a car simulator between 1400 and 1700h. Their sleepiness was enhanced by sleep restriction to 5h the night before. Following a pre-treatment 30-min drive and at the beginning of a 30-min break, participants were given double-blind 250ml energy drink (containing sucrose, glucose, 80mg caffeine, taurine, glucuronolactone and vitamins) vs. a control drink with the same volume and same taste but without caffeine, taurine and glucuronolactone. Compared with the control, the caffeinated energy drink significantly reduced sleep-related driving incidents and subjective sleepiness for the first 90 min of the drive. It was concluded that the caffeinated energy drinks are beneficial in reducing sleepiness and sleep-related driving incidents under conditions of afternoon monotonous driving following sleep restriction the night before.

In a 2001 study, in the Journal of Sleep Research, Belgian researchers, Valck & Cluydts, tested the effects of slow release caffeine on partial sleep deprivation and the driving abilities, on a driving simulator. 12 subjects between the age 20-25yrs were taken, and given 300mg slow release caffeine or a placebo. They were then tested for driving performance, sleepiness/alertness, and mood. The findings suggest that a lack of sleep can lead to a significant driving performance impairment, with drivers having problems to maintain an appropriate road position and a posted speed and more drivers getting involved in an accident. Secondly, the results indicate that caffeine and more specifically slow-release caffeine, can serve as a valuable countermeasure to these performance decrements, in the absence of any important side-effects, especially when its application is of an acute nature and when there is no opportunity to take a nap.

A 2006 study in the Annals of Internal Medicine, by a research team led by Pierre Philip, found that driving between 0200AM to 0500AM, increases the risk of traffic accidents by 5-6 times. The age group most susceptible to this is the one between 18-25. Nurses or physicians who often must stay awake for very long hours face the same risk. Traffic accidents occurring between the workplace and home are a major cause of injury and death among workers, and medical interns are particularly exposed.

The researchers designed a controlled, crossover study of real driving at night to study the effects of coffee or napping on night time driving performance. 12 healthy men were recruited as subjects, between the age group of 18-25. All participants performed 4 driving sessions: 1 session from 6:00 p.m. to 7:30 p.m. in the daytime and 3 sessions from 2:00 a.m. to 3:30 a.m. (coffee, decaffeinated coffee, or nap condition), with at least 1 week between sessions. Each participant drank 125 mL of instant coffee (about half a cup of coffee containing 200 mg of caffeine) or 125 mL of placebo (containing 15 mg of caffeine) 30 minutes before the night time driving session. All participants drove 200 km (125 miles) on the same highway in separate lanes (100 km [62.5 miles] one way and 100 km [62.5 miles] the other way) for all conditions. The night time driving session started 30 minutes after ingestion of coffee or placebo or 30 minutes after awakening from the nap.

The researchers found that, although caffeine and naps statistically significantly reduced sleepiness compared with placebo, no significant difference in fatigue was observed. This could be explained by the fact that coffee and a short nap mainly act on sleep–wake systems and not on central nervous systems involved in fatigue. Coffee and napping may not have exactly the same mode of action. Some participants respond very well to caffeine but do not improve greatly after a nap, while others benefit more from a short sleep than from caffeine. The researchers concluded that drinking coffee or napping at night statistically significantly reduces driving impairment without altering subsequent sleep.

To test the effects of coffee and napping on nocturnal driving in young and middle-aged people, a team of French researchers, led by Dr. Patricia Sagaspe, recruited twenty-four participants, 12 young (range 20-25 years) and 12 middle-aged (range 40-50 years). For the purpose of the study, a cup of coffee (200 mg of caffeine), a placebo (decaffeinated coffee, 15 mg of caffeine), or a 30-minute nap were tested. Participants drove 125 highway miles between 18:00 and 19:30 and between 02:00 and 03:30 after coffee, placebo, or a nap. The researchers found that, Caffeine improves driving performance in both young and middle-aged participants. Aging does not reduce the effectiveness of the response to caffeine. During the nap condition, younger drivers improved their performances much more than did middle-aged ones. Younger participants slept longer and more deeply than middle-aged ones and may have benefited from more restored functions.

A 2011 study, in the journal Psychopharmacology, by a team of researchers from Netherlands, led by Monique Mets, tested if Red Bull Energy Drink can counteract sleepiness and driving impairment during prolonged driving. For the study, 24 healthy individuals, divided into two groups, drove for 2hrs on a highway in a driving stimulator, and took a 15min break to have a Red Bull, or a placebo (Red Bull without the functional ingredients: caffeine, taurine, glucuronolactone, B vitamins (niacin, pantothenic acid, B6, B12, and inositol), and then drove for another 2hrs. The study proved that, Red Bull Energy Drink significantly improves driving performance and reduces driver sleepiness during prolonged highway driving. Red Bull significantly reduced the standard deviation of speed, improved driving quality, and reduced mental effort to perform the test during the 3rd hour of driving.

Taking all the above studies in consideration, researcher Susan Heatherley, of the University of Bristol, UK, questioned the effect of caffeine on sleep deprivation while driving, in her 2011 research in the journal Nutritional Neuroscience. She made the following glaring observations, which most people could have neglected:

  • It appears that caffeine does not have the ability to prevent severe sleepiness and should, therefore, not be used as a substitute for sleep.
  • These various results could indicate a net benefit of caffeine for simulated driving performance impaired by sleep restriction and deprivation. However, they are equally consistent with withdrawal reversal because, as the participants in these studies were caffeine consumers who were deprived of caffeine from the evening before the test day.

A team of Australian researchers, led by Lisa Sharwood, in an extensive study in the British Medical Journal, in 2013, evaluated 530 long distance drivers of commercial vehicles who were recently involved in a crash attended by police (cases) and 517 control drivers who had not had a crash while driving a commercial vehicle in the past 12 months. The researchers tested whether there is an association between use of substances that contain caffeine and the risk of crash in long distance commercial vehicle drivers. The researchers found that, 43% of drivers reported consuming substances containing caffeine, such as tea, coffee, caffeine tablets, or energy drinks for the express purpose of staying awake. Only 3% reported using illegal stimulants such as amphetamine (“speed”); 3,4 methylenedioxymethamphetamine (ecstasy); and cocaine. After adjustment for potential confounders, drivers who consumed caffeinated substances for this purpose had a 63% reduced likelihood of crashing compared with drivers who did not take caffeinated substances. They concluded that caffeinated substances are associated with a reduced risk of crashing for long distance commercial motor vehicle drivers.

A team of Serbian researchers, in the 2014 study in the journal Human-Transport Interaction Review, evaluated the driver’s attitude towards the consumption of coffee or energy drinks towards road safety. The researchers found that, “Fatigue is one of the important elements that affect the drivers and their behaviour while driving. In order to reach the destination earlier, many choose to eliminate fatigue by consuming beverages that will affect their central nervous system by removing fatigue and suppressing the need for sleep. They usually choose an energy drink that is sold in cans, easy to use and acting fast. Many studies indicated that the effects of energy drinks are strongest 30 minutes after consumption, and that their effect decreases during the next hour. Beside energy drinks, caffeine is also consumed, especially by older drivers. Caffeine is consumed in different ways, through fizzy drinks, chocolate, tea, but most often through coffee. Energy drinks and caffeine, which is the main ingredient of energy drinks, in large quantities might affect the health very adversely, thus affecting traffic safety, because large amounts of energy drinks may have effects similar to those of alcohol. They affect reflexes, perception and response of drivers. It was found that people who are over 55 almost never consume energy drinks, whereas 60% of respondents younger than 25 consume energy drink at least a couple of times a month. All age groups consume caffeine through coffee and tea, but the respondents who are under 55 consume it more than the older ones. We also found that respondents with higher education consume significantly more energy drinks when they are sleepy and need to drive than those with primary education. It should be emphasized that it is considerably better to drink a cup of coffee than a can of energy drink.”

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