Specialists in Fatigue Risk Management

UNDERSTANDING AND MANAGING MICROSLEEPS

Clockwork Research White Paper 18/01 March 2018 2 Understanding and managing microsleeps

WHAT IS THE RISK OF A MICROSLEEP?

If you have ever struggled to keep your eyes open to watch just one more episode of your favourite box set, or to stop your head nodding during an important afternoon meeting, you are familiar with the experience of microsleeps. These brief, involuntary lapses in perception of the outside world occur when we are tired. They last for 0.5 to 15 seconds, and are preceded by behavioural signs of sleepiness, such as yawning. When we experience microsleeps we are not fully aware of what is going on around us, which is why even if you do watch the episode or get through the meeting, you probably will not remember it well.

The consequences of microsleeps depend on the task you are completing when you experience them. While there are no repercussions for having microsleeps while reading a book in bed, microsleeps can be catastrophic if you are driving a tanker, administering medicine, or responding to an emergency call-out. In the US working population, 27% of people report unintentionally falling asleep on the job in the last month, and 16% of people reported experiencing at least one ‘near miss’ safety incident due to fatigue1. In the UK, it is not difficult to find a factory worker, pilot, nurse or security guard who has battled to keep their eyes open at work.

When we finish work and are feeling tired, we then undertake what is for many of us the riskiest task of the day – the drive home. Driving requires continuous vigilance and a microsleep can be fatal. In the UK, approximately 20% of road accidents are related to a driver falling asleep at the wheel, with 1 in 25 fatal road accidents caused by fatigue2. Fatigue related accidents are more likely to result in more severe consequences as a driver who has fallen asleep cannot brake or swerve to avoid or reduce the impact.

OF ROAD ACCIDENTS ARE RELATED TO DRIVERS FALLING 20% ASLEEP AT THE WHEEL

1 National Safety Council. (2017). Fatigue in the Workplace: Causes & Consequences of Employee Fatigue. 3 Understanding and managing microsleeps

HOW DO I KNOW IF I HAVE HAD A MICROSLEEP?

Microsleeps are a result of not having had adequate sleep, or being awake for an extended period. One study found that when sleep was reduced to only 4 hours, the following afternoon when participants completed a monotonous tracking task for 50 minutes, the number of microsleeps during the task increased to an average of 27.9, compared to 11.9 microsleeps when the participants had had an average of 8 hours sleep the previous night3.

Although we are reasonably good at knowing how tired we are, many people are unaware when they actually experience a microsleep, and will underestimate how many have occurred. For example, a study found that participants who had completed a 45-minute task starting at 01:30, that was designed to be simplistic and not mentally demanding, had on average 7.4 microsleeps. However, the participants themselves estimated that they had experienced only 2.9 microsleeps4. Therefore, we need to take steps to manage tiredness proactively, rather than waiting for the later signs of microsleeps, such as head nodding.

2 https://www.gov.uk/government/statistics/reported-road-casualties-great-britain-annual-report-2016

3 Innes, C.R., Poudel, G.R. and Jones, R.D. (2013). Efficient and regular patterns of nighttime sleep are related to increased vulnerability to microsleeps following a single night of sleep restriction. Chronobiology International, 30(9), pp.1187-1196.

4 Torsvall, L. and Åkerstedt, T. (1988). Extreme sleepiness: quantification of EOG and spectral EEG parameters. International Journal of Neuroscience, 38(3-4), pp.435-441., Reviewed in Kennedy, G., Howard, M. and Pierce, R. (2001). Microsleep Literature Review. 4 Understanding and managing microsleeps

WHEN DO MICROSLEEPS OCCUR?

Microsleeps occur most frequently when we are tired, in the afternoon, at night, and during monotonous tasks. Shiftworkers can be especially vulnerable to microsleeps, because they are often simultaneously exposed to these factors - examples could be a sleep-deprived nurse filling out routine paperwork while on nightshift, or a security professional who has had 4 hours of sleep and is providing round-the-clock surveillance.

A U.S. ESTIMATE OF IS LOST IN PRODUCTIVITY PER EMPLOYEE PER YEAR $1967 DUE TO SLEEP LOSS9

Microsleeps are most likely to occur during the times of day when our circadian rhythm in alertness is low, i.e. during the mid-afternoon and night. Circadian rhythms are 24-hour rhythms generated by a cluster of cells in our brain known as our body clock. Humans are diurnal, meaning that our alertness is high when we are awake during the day, and low at night, when we are sleepy and prone to microsleeps. We also experience a circadian dip in alertness during the mid-afternoon. This is one biological reason for the mid- afternoon siesta that is common in some societies, and is also the reason for the increase in microsleeps that we are likely to experience around this time of day.

Nightshift workers, many of whom are chronically sleep deprived, and are awake all night, face an increased risk of accidents when driving home following a night shift. Nightshift workers have been shown to experience microsleeps on a post-nightshift drive at more than twice the rate of a post sleep drive5. Driving performance also dramatically decreased with workers having significantly more emergency braking manoeuvres and lane excursions on a post-nightshift drive. A study in nurses showed, at their most tired, driver’s eyes were closed for over 7% of each minute on the post-nightshift drive home, which for a 30 minute drive travelling at 30mph translates to driving over 1 mile with closed eyes6.

Research has shown that microsleeps are more prevalent during simple, non-engaging tasks7, and increase with time on the task. This means that the longer a task is performed, the more microsleeps are likely to occur. A study in airline pilots showed that rate of microsleeps was higher during cruise, where workload is low, compared to take-off and landing, which are tasks that are more complex. The rate of microsleeps also increased as the flight progressed, where the rate of microsleeps doubled after flying for 7 hours during the day and quadrupled after just 3 hours of flying at night8.

5 Lee, M.L., Howard, M.E., Horrey, W.J., Liang, Y., Anderson, C., Shreeve, M.S., O’Brien, C.S. and Czeisler, C.A. (2016). High risk of near-crash driving events following night-shift work. Proceedings of the National Academy of Sciences, 113(1), pp.176-181.

6 Ftouni, S., Sletten, T.L., Howard, M., Anderson, C., Lenné, M.G., Lockley, S.W. and Rajaratnam, S.M. (2013). Objective and subjective measures of sleepiness, and their associations with on-road driving events in shift workers. Journal of Sleep Research, 22(1), pp.58-69. 7 Buckley, R.J., Helton, W.S., Innes, C.R., Dalrymple-Alford, J.C. and Jones, R.D. (2016). Attention lapses and behavioural microsleeps during tracking, psychomotor vigilance, and dual tasks. Consciousness and Cognition, 45, pp.174-183.

8 Samel, A., Wegmann, H.M. and Vejvoda, M. (1997). Aircrew fatigue in long-haul operations. Accident Analysis & Prevention, 29(4), pp.439-452.

9 Rosekind, M.R., Gregory, K.B., Mallis, M.M., Brandt, S.L., Seal, B. and Lerner, D. (2010). The cost of poor sleep: workplace productivity loss and associated costs. Journal of Occupational and Environmental Medicine, 52(1), pp.91-98 5 Understanding and managing microsleeps

INEFFECTIVE MANAGEMENT OF MICROSLEEPS

When we experience microsleeps, many of the things we do to try to stay awake are not effective. We try to look awake, but microsleeps can occur with our eyes open or closed. We try to stay focused, but we cannot stop our brain from drifting towards sleep. We stand up when our head starts to nod, but we can sleep on our feet. Ineffective strategies we use while driving include winding down the window, and turning up the radio10. This might give us a short burst of alertness, but ultimately does not prevent microsleeps.

10 Reyner, L.A. and Horne, J.A. (1998). Evaluation of ‘in-car’countermeasures to sleepiness: cold air and radio. Sleep, 21(1), pp.46-51. 6 Understanding and managing microsleeps

EFFECTIVE MANAGEMENT OF MICROSLEEPS

Microsleeps are not as rare as we might like to think. Many of us do not get our ideal amount of sleep each night, and as a consequence, we experience cumulative sleep loss, and do not perform or feel at our best. This can happen for many reasons, such as extended work hours, social or family commitments, or sleep disorders.

To manage microsleeps effectively, we need to recognise that they are a sign of severe sleepiness. Microsleeps occur when we are so tired that our brain snatches brief periods of sleep against our will and without our knowledge. When we are showing the signs of a microsleep, our cognitive performance is already impaired, and has been for a while. Therefore, if you are struggling to keep your eyes open, or your head is nodding, it is time to stop what you are doing, get some sleep, and come back when you are alert.

Once microsleeps start, sleep is the only real solution, and in some workplaces, employees are able to take a nap in a controlled manner. Caffeine can provide short-term relief from sleepiness, but it is a temporary solution. Caffeine can also disrupt sleep if it is consumed 4-6 hours before bed, leading to a vicious cycle of sleep loss and consequent microsleeps.

Rather than responding to the occurrence of microsleeps, we need to look at proactive strategies for limiting sleepiness in the first place. At Clockwork Research, we help organisations working in safety critical industries, such as aviation and medicine, to understand and quantify the incidence of microsleeps among their employees. Microsleeps are not usually often reported at work, because employees aren’t aware of their significance for safety, or are concerned about a possible negative response from management. The organisations and employees are often surprised to learn how often microsleeps occur, even during the most safety-critical tasks.

All drivers need to be particularly careful to ensure that they are well rested before starting a long drive on the motorway, and as soon as they are yawning, pull over and have a nap. Examples of strategies for limiting microsleeps in the workplace include schedules that are designed to consider the science of sleep and circadian rhythms; regular breaks; additional pilots on flights to enable the crew to take longer in-flight breaks in the bunk; improved hotels for people who travel for work; and reviewing on-call working arrangements. These strategies reduce microsleeps, and enable the organisations to thrive and benefit from having a safe, well-rested, and efficient workforce. Specialists in Fatigue Risk Management

Clockwork Research Ltd 201 Borough High Street, London, SE1 1JA

Tel: +44 (0) 203 805 7792 www.clockworkresearch.com

Design: PadCreative.co.ukApril 2014