Here’s an alertness tip straight from the beach! Ever wonder how lifeguards stay alert, even on those hot and humid dog-days of summer? They practice a technique that is known in the lifeguarding industry as the “Five-Minute Scanning Strategy.”

Every five minutes, lifeguards will change their postures (for example they’ll go from sitting to standing, walking) and also count the number of swimmers in their area. The combination of the mental and physical activity every five minutes helps keep them alert and responsive throughout their shift.

The “Five-Minute Scanning Strategy” was developed by Tom Griffiths, a Penn State University professor who studied thousands of lifeguards around the world. He found that after 15 minutes of performing a simple task, a person’s performance starts to get worse.

By breaking up a task into 5-minute blocks, you can improve performance. His research is applicable to anyone working in a safety-sensitive task that is at risk for fatigue: try changing your posture on a routine basis. Looking for more Working Nights Tips, subscribe to our Working Nights Newsletter.


Friday, 12 September 2014 19:21

Noise and Alertness: 5 Facts You Should Know

Why can soothing music or “white noise” can put you to sleep, while a loud alarm every five minutes has the opposite effect? Noise and alertness have a complex relationship.

Research finds that even the same noise can evoke varied responses in different individuals. For example, a study that simulated an assembly line found noise actually improved the speed of air conditioner assembly but reduced the speed for carburetor assembly1.

While noise’s effects aren'tt yet perfectly understood, consensus exists on a number of points:

1. Continuous loud noise is dangerous and can cause hearing loss
The National Institute for Occupational Safety and Health (NIOSH) recommends that the noise level not exceed 85 decibels (dB) —comparable to the sound of a lawnmower or electric drill. According to NIOSH, one in eight people exposed to a noise level over 85 dB develop hearing loss.

2. Continuous loud noise may reduce performance.Noise’s effect on performance depends on what kind of work one performs. For example, noise’s effect is negligible if a person has to react at certain definite times, receives clear warning signals, and has an easily visible stimulus, according to research. But problems arise when people perform a monitoring task for a long time and warning signals are less clear, or a task has several components.

Although performance problems may not always show up in lab tests, it’s still a good idea to minimize the noise level as much as possible. Along with effects on performance and hearing, excessive background noise can cause stress and anxiety and interfere with memory and learning.

 3. “White noise” causes on-the job problems for shift workers
White noise — a mix of sound waves extending over a wide frequency range — is commonly generated by engines, computers, and machinery. At work, white noise often has the effect of lulling people to sleep, especially shift workers struggling to stay awake during the overnight hours.

4. Technology can reduce noise.
There are specially-designed headsets that can reduce the external noise level by about 23 dB and allow wearers to listen to music that automatically mutes when a co-worker or supervisor needs to communicate.

5. Noise cancellation may minimize the effects of noise on alertness.
Noise cancellation devices are often built into earmuffs and produce a low-frequency noise wave that is the exact mirror image of the existing noise. Sometimes called “anti-noise,” these devices do not eliminate noise altogether, but they provide 15-20 dB of noise reduction. If your work environment has a lot of loud noise, or continuous white noise, suggest noise cancellation headphones to your shift workers.


Tuesday, 02 September 2014 18:43

Understanding Human Operating Procedures

“People don’t release smoke, grind gears, or have pieces fall off; but their equivalents – fatigue, error, injury, and ill heal
h do result in failure and breakdown."

Martin Moore-Ede, M.D., Ph.D., The Twenty-Four-Hour Society

While our technologies and operations have dramatically changed since the 1993 publication of The Twenty-Four-Hour Society, this statement remains as true as ever.

Why? Because like machinery, we aren’t designed to work outside of our limitations.

Below is an excerpt from The Twenty-Four-Hour Society, written by Martin Moore-Ede, M.D., Ph.D., which details the dangers of operations that are disproportionally machine-centric instead of people-centric.

The discrepancies between these mindsets are foundational to the safety and health of workers and the overall well-being of the operations.

The Twenty-Four-Hour Society: Design Specs of the Human Machine

SOME YEARS AGO I had an opportunity to work with some of the engineers who were designing the crew cabin of the space shuttle. Having been involved with NASA biomedical experiments since the Apollo moon mission days, I was invited to serve on a NASA expert panel advising on human factors considerations for the shuttle. For a young scientist, to work with the best in American engineering – the men and women who had put human beings on the moon – was a thrilling opportunity.

As we looked at several possible crew cabin configurations, my biomedical colleagues and I strongly urged NASA to abandon one scheme, which we felt almost guaranteed that the crew’s blood circulation would be drawn out into the legs during landing, causing unconsciousness. Despite our protests, we were eventually told that the engineers had selected this design.

A year later I learned that the design had subsequently been abandoned in favor of one of the others we preferred. When I expressed delight that the biomedical concerns had finally been acknowledged, I was told the reason for abandoning the previously selected design: undue stress from G-forces would damage the wings. We got the design we wanted, but we had done nothing to alter the mind-set of the engineers!

In most cases of discrimination one group discriminates against another, but here we have a case of discrimination against ourselves.

We treat our man-made machinery better than the bodies of the people who operate it. Machines are protected by operational manuals, warning labels, and training courses. Humans arrive in this world with no such protection. We tend to assume that people are adaptable, but that is true only within narrow limits.

A manager of an industrial plant or a pilot of a plane or a NASA space shuttle, who operated a complex piece of machinery outside of the specifications for which it was designed would be deemed reckless and irresponsible.

Operating a machine out its design specs, at too many rpm, too high a G-force, too high a temperature, or too low a pressure, creates unnecessary risks of breakdown or failure. Yet the most highly sophisticated pieces of machinery in that industrial plant, airplane, or space shuttle are not the complex electronic man-made systems, but rather the bodies and brains of the human operators or pilots.

People believe that machinery is inherently unreliable and must constantly be watched. Yet, with the advances in modern engineering, it is the human operator, more than the machine itself, that needs watching.

We hire people to watch the equipment in our factories, nuclear power plants, and airplanes, but we don’t have the equipment watch the person to ensure that he or she is awake and alert. We have the weak link of the chain watching the strong link, but not the strong watching the weak – the fallible watching the infallible, rather than the infallible watching the fallible.

Because we have been machine-centered in our thinking – focused on the optimization of technology and equipment – rather than human-centered – focused on the optimization of human alertness and performance, the reliability of machines has grown enormously in the twentieth century, while human reliability has tended to decline.

Human error has become the problem of our age because of the trade-offs and compromises, made to ensure the technological achievements of the modern world, have not taken into account the design specs of the human body. Creating and installing a human-centered technology to redress the balance will be one of the most important challenges of the twenty-first century.

The shocking truth is that we know far less about the design specs of the human being than we know about the hardware and software he or she operates. And we tend to abuse those design specs, particularly in around-the-clock operations, which are the core of our twenty-four-hour society.

People don’t release smoke, grind gears, or have pieces fall off; but their equivalents – fatigue, error, injury, and ill health – do result in failure and breakdown.

Source: Martin Moore-Ede, The Twenty-Four Hour Society: Understanding Human Limits in a World That Never Stops, Addison-Wesley 1993.


CIRCADIAN® is the global leader in providing 24/7 workforce performance and safety solutions for businesses that operate around the clock.  Through a unique combination of consulting expertise, research and technology, software tools and informative publications, CIRCADIAN helps organizations with traditional and/or extended operating hours optimize employee performance and reduce the inherent risks and costs of sleep deprivation and fatigue.
Thursday, 24 July 2014 21:18

The Nine Switches of Human Alertness

Construction worker
Right now, take a moment and estimate how alert you are on a scale of 1 to 10. Now, go a step further and try to pinpoint what factors are influencing your alertness levels.

In his book, The Twenty-Four Hour Society, Dr. Martin Moore-Ede identifies how a person’s alertness is triggered by nine key internal and external factors that can be considered the switches on the control panel of the mind.

Understanding these 9 key switches and how to manipulate them is the secret of gaining power over one of the most important attributes of the human brain: alertness.

Here are 9 switches – recognizing them can help you stay alert on the job.

1.  Sense of danger, interest or opportunity
Nothing pulls us faster from a drowsy state than the imminent threat of danger, or just surviving a near miss. The emergency fight-or-flight response is activated by the sympathetic nervous system, and the brain is placed on full alert. However, it is important to note that the presence of danger is not enough; the danger must be perceived and feared.

Although less extreme than the response to danger, a stimulating task or opportunity triggers a similar response. The flip-side is that alertness fades if what you’re doing is monotonous. An endless stretch of freeway or a quiet night in a plant where everything is running smoothly can prompt drowsiness.

2.  Muscular Activity
Physical activities such as walking or stretching also trigger the sympathetic nervous system and help keep you alert. However, many jobs require us to be sedentary. Extended periods without much movement, such as sitting in a chair or car, can make it difficult to stay fully alert or even awake.

3.  Time of day on the circadian clock
Circadian rhythms – daily ups and downs in body temperature, blood pressure, hormone levels and other physiological traits – have a major effect on alertness. We generally experience peak levels of alertness in the morning and early evening and lowest levels of alertness in the early afternoon and during the overnight hours.

4.  Sleep bank balance
How long you’ve been awake and how much sleep you’ve had in recent days affects your alertness level. If you only sleep four or five hours a day for several days, you build up a “sleep debt” that leads to reduced alertness. A long spell of sleep acts as a “deposit” that offsets your sleep debt.

5.  Ingested nutrients and chemicals
Caffeine and amphetamines temporarily increase alertness. Others, such as sleeping pills, antihistamines, melatonin and certain foods, may induce sleep. Of course, some of these substances have serious drawbacks because of their negative effect on overall health and potential for abuse or addiction.

6.  Environmental light
Bright light tends to increase alertness, particularly during the over-night hours. Whether you’re at home or on the job, dim light or darkness set the stage for falling asleep.

7.  Temperature and humidity
Cool, dry air, especially on your face, makes it easier to stay alert, while heat and humidity make you drowsy. Similarly, a cold shower is invigorating, while a warm bath prepares you for sleep.

8.  Sound
As you know, sound can be both a tool for promoting sleep and increasing alertness. Be conscious of the sound around you and adjust it to fit what you need. For example, the soft hum of computers in the middle of the night might lull you into sleep.

9.  Aroma
Some researchers believe that aromas like peppermint, pine and citrus can make people more alert. Lavender, meanwhile, seems to have a sedative effect.

At first glance the Nine Switches of Alertness may seem obvious and straightforward. However, many workplaces have not embraced the 'switches' to increase the alertness of their workforce.

One challenge is that the human desire for comfort intervenes. Making oneself comfortable is not compatible with optimal alertness, especially during the wee hours of the morning. In fact, the desire for comfort may be so dominant, and lack of awareness of the compromise one is making with alertness so large, that alertness takes a back seat.

Take for example, high-tech industrial control rooms that are being built around the world. Many of them are more focused on human comfort than on alertness because of the belief that comfort equals improved performance. However, the truth is that sometime to be fully alert one must be a little uncomfortable.

Want to learn more about alertness and human fatigue? Visit to download a free white paper about human fatigue.

Source: Martin Moore-Ede, The Twenty-Four Hour Society: Understanding Human Limits in a World That Never Stops, Addison-Wesley 1993.


CIRCADIAN® is the global leader in providing 24/7 workforce performance and safety solutions for businesses that operate around the clock.  Through a unique combination of consulting expertise, research and technology, software tools and informative publications, CIRCADIAN helps organizations with traditional and/or extended operating hours optimize employee performance and reduce the inherent risks and costs of sleep deprivation and fatigue.

Thursday, 10 July 2014 18:57

10 Dangers of a Sleep Deprived Workforce

tired sleep deprived worker With two-thirds (63%) of Americans reporting that their sleep needs aren’t met during the week, sleep deprivation is a societal epidemic that exists across all countries, economic statuses, industries, and seniority levels.1

Sleep deprivation is an issue that is often ignored, yet frequently the root cause of decreased productivity, accidents, incidents and mistakes which cost companies billions of dollars each year. Often companies are unaware of the impact fatigue or sleep deprivation is having on their operation until a tragic accident occurs… only then do managers ask the question: “What happened?”

Here are 10 dangers of having a sleep deprived workforce:

1. Decreased Communication
When workers are tired, they become poor communicators. In one study, researchers noted that sleep deprived individuals:

  • drop the intensity of their voices
  • pause for long intervals without apparent reason
  • enunciate very poorly or mumble instructions inaudibly
  • mispronounce, slur or run words together
  • repeat themselves or lose their place in a sentence sequence

2. Performance deteriorations
Performance declines frequently include increased compensatory efforts on activities, decreased vigilance, and slower response time. The average functional level of any sleep deprived individual is comparable to the 9th percentile of non-sleep deprived individuals.

Workers must notice these performance declines, right? Not quite. In fact, sleep deprived individuals have poor insight into their performance deficits. Also, the performance deficits worsen as time on task increases.3

3. Increased risk of becoming distracted
Sleep deprived individuals have been shown to have trouble with maintaining focus on relevant cues, developing and updating strategies, keeping track of events, maintaining interest in outcomes, and attending to activities judged to be non-essential. In fact, research suggests that there is a symbiotic relationship between sleep deprivation and attention-deficit hyperactivity disorder (ADHD) due to the overlap in symptoms.4

4. Driving Impairments
Due to federal regulations, the trucking industry is well aware of the driving impairments associated with sleep deprivation; however, plant managers are unaware of the ways in which sleep-deprived workers may be dangerously operating machinery (e.g. forklifts or dump trucks). In fact, 22 hours of sleep deprivation results in neurobehavioral performance impairments that are comparable to a 0.08% blood alcohol level - that’s legally drunk in the United States.5

5. Increased number of errors
The cognitive detriments of sleep deprivation increase concurrently with a worker’s time on a given task, resulting in an increased number of errors. These errors include mistakes of both commission (i.e. performing an act that leads to harm) and omission (i.e. not performing an expected task), which can wreak havoc at any work facility. Errors are especially likely in subject-paced tasks in which cognitive slowing occurs, and with tasks that are time-sensitive, which cause increases in cognitive errors.3

6. Poor cognitive assimilation and memory
Short-term and working memory declines are associated with sleep deprivation and result in a decreased ability to develop and update strategies based on new information, along with the ability to remember the temporal sequence of events.3

7. Poor mood appropriate behavior
Inappropriate mood-related behavior often occurs in outbursts, as most sleep deprived individuals are often quiet and socially withdrawn. However, a single one of these outbursts can be enough to destroy the positive culture of a work environment and cause an HR nightmare.

These behavioral outbursts can include irritability, impatience, childish humor, lack of regard for normal social conventions, inappropriate interpersonal behaviors and unwillingness to engage in forward planning.2

8. Greater risk taking behavior
Brain imaging studies have shown that sleep deprivation was associated with increased activation of brain regions related for risky decision making, while areas that control rationale and logical thinking show lower levels of activation. In fact, sleep deprivation increases one’s expectation of gains while diminishing the implications of losses.6

What does this mean for your workers? Sleep deprived workers may be making riskier decisions, ignoring the potential negative implications, and taking gambles in scenarios in which the losses outweigh the benefits.

9. Inability to make necessary adjustments
Flexible thinking, preservation on thoughts and actions, updating strategies based on new information, ability to think divergently, and innovation are all negatively impacted by sleep deprivation. A worker may be unable to fill a leadership role on request when sleep deprived, resulting in a frustrated management team.

10. Effects of sleep deprivation compound across nights
Four or more nights of partial sleep deprivation containing less than 7 hours of sleep per night can be equivalent to a total night of sleep deprivation. A single night of total sleep deprivation can affect your functioning for up to two weeks.3 To your brain, sleep is money and the brain is the best accountant.

The Conclusion: Rather When Than If

The moral of the story is the following: when you have sleep deprived or fatigued workers, your productivity levels and quality of work will be compromised. Furthermore, you will be creating an environment where it becomes not a matter of if your workplace will have an accident or incident but a matter of when, and to what magnitude.

Clearly sleep deprivation is no laughing matter, no matter how frequently our society treats the issue light-heartedly. Eventually our biological drive to compensate for sleep deprivation wins at the end of the day, and the loser might be your workers, your company, or even yourself.

Luckily, there are a variety of ways to monitor, manage, and mitigate the effects of sleep deprivation, such as biocompatible shift scheduling or corporate sleep education seminars. Want to learn more about the ways to keep your workplace safe from fatigue-related accidents?

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To help you manage the cost of fatigue, this white paper will:

• Review business practices which increase fatigue risk
• Examine the consequences of fatigue in the pulp/paper industry and other 24-hour operations
• Calculate the bottom-line costs of fatigue
• Provide solutions for mitigating the costs, risks and liabilities of fatigue




  1. National Sleep Foundation (2011, March 7). Sleep In America Poll. Retrieved from:
  2. Harrison, Y., & Horne, J. A. (2000). The impact of sleep deprivation on decision making: a review. Journal of Experimental Psychology: Applied, 6(3), 236.
  3. Durmer, J. S., & Dinges, D. F. (2005, March). Neurocognitive consequences of sleep deprivation. In Seminars in neurology (Vol. 25, No. 1, pp. 117-129).
  4. Owens, J. A. (2005). The ADHD and sleep conundrum: a review. Journal of Developmental & Behavioral Pediatrics, 26(4), 312-322.
  5. Dawson, D., & Reid, K. (1997). Fatigue, alcohol and performance impairment. Nature, 388(6639), 235-235.
  6. Venkatraman, V., Chuah, L., Huettel, S., & Chee, M. (2007). Sleep deprivation elevates expectation of gains and attenuates response to losses following risky decisions. Sleep, 30(5).

Are you capitalizing on the benefits of workplace power naps?

If not, your company may be losing money due to tired and dragging employees. With competition at its fiercest, many companies are searching for any way to boost employee productivity and have turned to sleep scientists who state that daytime napping is built into our biology and comes with many brain boosting benefits. If you don't believe us, take a look at our infographic about 'Napping in the Workplace'

So before you write off napping as a leisurely activity that should be banned at work, you might want to consider the ways in which napping at your workplace could make for happier, more productive employees, while also putting more money in your company's piggy bank.

energy drinksWith sleep constantly challenged by the demanding nature of our daily lives. Many of us resort to energy drinks and other caffeinated beverages to power through the day. But do you ever wondering how your body is affected by these drinks? Are they healthy? Moreover, are they safe?

Below are five crucial facts that you need to know before consuming your next energy drink. Knowing these facts could benefit your health and potentially save your life.

1. Energy drinks require no FDA preapproval when choosing ingredients

Traditional sodas are considered to be beverages, and therefore are subject to strict FDA regulations on caffeine contents and ingredients. On the other hand, energy drinks are classified as dietary supplements, and have avoided many FDA regulations due to a loophole created by the Jolt Cola beverage company. Because of this, energy drink ingredients must be listed, however there’s no requirement to list the specific amount of each ingredient existing in these “drinks”.1

2. Per ounce, energy drinks can contain over 5x more caffeine than regular coffee

Energy shots, like 5-Hour Energy, contain 100 mg of caffeine per ounce as compared to regular coffee, which contains approximately 18 mg of caffeine per ounce.2 What does this mean for the typical energy drink consumer?

Well, unlike hot coffee, which is often sipped slowly, energy drinks tend to be “gulped,” and are finished quickly. Therefore, the peak caffeine level of an energy drink will be reached quickly. With a long half-life, energy drink users can quickly find themselves in danger of reaching very high levels of caffeine in the body, especially after consuming several drinks in a short amount of time.

3. The half-life of caffeine in energy drinks can last up to 10 hours

The human body absorbs 99% of caffeine, reaching peak levels within 30-75 minutes.3,6 How long does this caffeine rush last? Well the half-life of caffeine can vary dramatically, with its effects lasting anywhere from 2.5–10 hours.4 There are several factors that can influence the half-life of caffeine, such as: 3-7

    • Impaired liver function
    • High levels of caffeine consumption (increases half-life)
    • Cigarette smoking (decreases half-life)
    • Weight
    • Age
    • Medications (i.e. oral contraceptives, antibiotics, theophylline, Echinacea)
    • Health Status
    • Gender
    • Individual differences

4. A variety of physiological side effects are associated with heavy caffeine use

There are no hard and fast rules on how much caffeine is safe, as caffeine sensitivity can vary widely depending on the individual; however, several major medical organizations have published guidelines for caffeine intake. For example, the Mayo Clinic recommends that people consume no more than 200-300mg of caffeine per day, which equates to roughly one 5-Hour Energy Shot.

In fact, one study found that people given a 300 mg shot of caffeine experienced the following symptoms (in order of prevalence):

    • Restlessness or muscle tremor
    • Heart palpitations
    • Dizziness
    • Headache
    • Diarrhea
    • Wakefulness
    • Polyuria (excessive urination)
    • Increased sweating
    • Abdominal pain
    • Ear/eye problems
    • Vomiting or nausea
    • Delirium

5. Energy drinks have been linked to death and cardiac failure

Between 2004 and 2012, 5-Hour Energy amassed 92 incident reports with 13 fatalities, Monster had 40 reports with 5 fatalities, and Rockstar had 13 reports with no fatalities. Over 50 of the incidents for all three energy drinks list heart problems (chest pain, arrhythmia, cardiac arrest, etc.) in the events, according to the U.S. Food and Drug Administration.

In 2012, Monster Energy received a great deal of attention, when the FDA published a report listing

Monster Energy drinks as a possible contributing factor to the deaths of five people over three years. One of those people was a 14-year-old Maryland girl, whose death certificate stated that she died of “cardiac arrhythmicity due to caffeine toxicity” after drinking two 24-ounce cans of Monster in 24 hours, which exacerbated a pre-existing heart condition. The family of the girl is now suing Monster Energy for failing to provide adequate warnings about the risks of consuming their drinks.

It can’t be all bad, right?

While the majority of studies published on energy drinks focus on the negative effects, not everyone agrees with their assessments. For example, energy drinks do appear to enhance physical performance. Drinking energy drinks also improves driving performance in sleepy subjects – including reducing driving mistakes, swerving, and self-reported sleepiness and alertness.9

So is it safe to have an energy drink?

Bottom line: Yes, but use energy drinks in moderation. If you can’t get going in the morning or are dragging during the middle of your night shift, an energy drink now and then is fine. But remember, whether you get your caffeine from energy drinks, soda, or coffee, read the labels (or do some research) and be aware of the levels of caffeine and other ingredients you’re putting in your body. As long as you use caution and keep track of what you’re consuming, feel free to enjoy the benefits of energy drinks – without ignoring the risks.

Want to learn more about energy drinks? Visit CIRCADIAN to download a free white paper titled

Energy Drinks: The Good, the Bad, and the Jittery that provides further information about energy drinks.


1. Energy “Drinks” and Supplements: Investigations of Adverse Event Reports. U.S. Food and Drug Administration. Accessed June 20, 2014.
2. Caffeine in coffee: US Food and Drug Administration
3. Carrillo JA and Benitez, J (2000) Clinically significant pharmacokinetic interactions between dietary caffeine and medications. Clinical pharmacokinetics, 39: 127-153.
4.Kaplan GB, Greenblatt DJ, Ehrenberg BL, Goddard JE, Cotreau MM, Harmatz, JS and Shader RI (1997) Dose-dependent pharmacokinetics and psychomotor effects of caffeine in humans. Journal of Clinical Pharmacology, 37:693-703.
5.Caffeine. How much is too much? Mayo Clinic. Accessed on June 20, 2014.
6.Mandel, HG (2002) Update on caffeine consumption, disposition and action. Food and Chemical Toxicology, 40:123
7.Magkos F, and Kavouras S (2005) Caffeine use in sports, pharmacokinetics in man, and cellular mechanisms of action. Crit Rev Food Sci Nutri 2005, 45: 535-562.
8.Carrillo JA and Benitez J (1996) CYPlA2 activity, gender and smoking, as variables influencing the toxicity of caffeine. British Journal of Clinical Pharmacology, 4(1): 605-608.
9.Reyner LA, and Horne JA (2002) Efficacy of a ‘functional energy drink’ in counteracting driver sleepiness. Physiological Behavior, 75(3): 331–335.

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