“Night shift workers in any occupation are 30% more likely to make a mistake than their day-shit counterparts.” (Costa G. et al: Shift work and occupational medicine, Occupational Medicine 2003; 55:83-88)
Across the developed world roughly 15% of the working population are shift workers. It will come as no surprise that shift work is associated with tiredness and fatigue. But what might come as more of a surprise is the evidence which supports the extent of the health and performance consequences and the link to poor sleep in shift workers.
According to research conducted by NASA, 75% of shift workers report sleepiness on the job, with 20% having fallen asleep on the job in the last 12 months. 20% of shift workers report frequently or occasionally making errors due to sleepiness. 29% indicated that sleepiness interferes with daily work activities a few days a week and 68% of shift workers report sleeping problems a few days a week.
“Our people are our most important asset.” You often hear it said and printed in company literature – especially recruitment literature. But is this really the case? Are companies taking adequate measures to protect their shift workers from health, safety and performance repercussions?
The effects of shift work on health
From minor health conditions such as cold and flu, high cholesterol, nausea, anxiety, stomach complaints and memory problems through to more serious chronic conditions such as cancer, heart disease, obesity and diabetes a number of recent studies have linked shift work with poor health.
The International Agency for Research on Cancer (IARC) has classified shift work that disrupts the body's circadian rhythm (body clock) as a cancer causing agent. Numerous studies have shown the link between shift working and certain types of cancer – in particular breast and ovarian cancer in women and prostate cancer in men.
There have also been numerous studies showing a link between shift work and heart disease, obesity and diabetes as well as mental ill health, brain damage and heavy drinking. There is more information on where to find the specific studies later in the blog.
To the extent there is a consensus on the reasons why shift working is linked to poor health outcomes then it revolves around the hormonal changes that occur when exposed to light at night.
The effects of shift work on performance
Alongside the additional health risks associated with shift work there are also considerable performance consequences arising from: insomnia, fatigue, poor memory, headaches, difficulty concentrating, irritability and depression. As we will explore later there is a significant correlation between the adverse performance effects of shift working and difficulty obtaining sufficient good quality sleep.
For those of you who read our ‘Examining the need for programmes to tackle tiredness and fatigue in safety-critical operations’ presentation you will have seen numerous examples of where tiredness and fatigue led to major accidents and incidents. There have been other recent incidents which highlight the issue of tiredness and fatigue in shift workers.
Chicago Transit rail crash: At 03:00 on 24th March 2014 a Chicago Transit train failed to stop at the last station causing it to mount the platform and barrel up an escalator. 32 people were injured and taken to hospital. The investigation found that the driver, who was employed on a “fill-in” basis to cover “whatever shift needed covering” fell asleep at the controls and only woke up as the train left the rails. This was the second time this driver had had a fatigue-related incident in 3 months.
MetroNorth rail crash: On 1st December 2013 a MetroNorth commuter train hit a curve in the track with a 30 miles per hour speed limit at 82 mph. The train derailed and careered down an embankment stopping just short of a river. 4 people were killed and 70 injured. The driver, who had recently moved from late night to early morning shifts said he felt strangely dazed just before the crash. A medical examination after the crash also found the driver to have severe (undiagnosed) sleep apnoea.
Three Rivers bus crash: In January 2014 a passenger van transporting oil field workers back from a 24-hour shift slammed into a school bus in the early morning. Seven of the twelve school children were taken to hospital and treated for their injuries. Three of the passengers in the van died. Police said there was no sign the driver made an attempt to stop and that driver fatigue was the likely cause. Police said companies need to educate staff on the dangers of driving after a shift.
So where exactly does sleep deprivation fit in?
Night shift and rotating shift workers who have to sleep during the day will suffer from considerable circadian disruption and will find it particularly difficult to obtain sufficient good quality sleep. The consensus is that this is due to light exposure and hormonal changes which come as a result of circadian disruption.
As far back as 1980 Professor Czeisler and colleagues ran an objective study (via EEG) which showed that rotating shift workers obtained between 1 and 4 hours less sleep when sleeping during the day than when they slept at night.
More recently data presented by the Centers for Disease Control, from the 2010 National Health Interview Survey found that 44% of night shift workers obtained less than 6.5 hours of sleep a night. This rose to 70% in transportation and 52% in healthcare workers. 32% of those working ‘other’ shift patterns, including rotating shifts, sleep less than 6.5 hours a night.
These statistics should concern every shift worker and every employer. Most leading sleep scientists recommend we obtain 7 to 8 hours of good quality sleep every night. Below 7 hours and more so as sleep duration falls even lower our alertness becomes impaired. This is compounded when unable to obtain sufficient good quality sleep over two or more consecutive days.
Poor sleep has also, on its own been, linked to increased incidence of minor ill health and chronic conditions – the very same chronic conditions as for shift working. Similarly poor sleep has also been linked with poor performance, because sleep deprivation results in numerous physical and cognitive impairments.
When tired our reaction times diminish, we have difficulty concentrating, our memory suffers, we find it more difficult to cope with tasks, our ability to think logically and creatively is diminished, we find it difficult to assimilate new information and our decision making becomes impaired. Our speech becomes slurred and our vocabulary suffers leading to poor communication. Our mood also falters.
According to the Harvard Business Review sleeping 4 to 5 hours a night for a week impairs performance to the same extent as being legally drunk. A study undertaken at Pennsylvania University found that after 2 weeks of sleep restriction those restricted to 6 hours of sleep a night made eleven times more errors in tests throughout the day at the end of the two weeks than when they were well rested. This rose to fourteen times in those restricted to 4 hours sleep.
So for those organisations who run seven day (plus) shift cycles – are you asking your staff to perform the same tasks, particularly tasks which require sustained vigilance, on the final day of their shift as were required on the first day of their shift?
So how should a comprehensive fatigue management programme for shift workers look?
We believe that there 4 key elements to a programme which tackles common issues in shift workers.
- Awareness – raising awareness amongst key management personnel
- Policies and procedures review – with a specific focus on your industry
- Train-the-trainer – engaging key management, health & safety and training personnel
- Education – educating staff from the top down using a variety of media on an ongoing basis.
Awareness: The key to tackling any business issue is to understand the extent, impact and causes of the problem. Initially staff should undertake an assessment, which gives them immediate feedback and personalised advice. The organisation needs to understand the composite results and be able to compare different job roles or shift schedules to identify the key problem areas. This composite report is key to raising awareness amongst key management personnel and to scope and build interventions to target specific issues within the business.
Policies and procedures: The first step in the review of policies and procedures is to share the findings from the assessments with the group leadership team. This will provide a solid base, founded on actual evidence, on which to build policies and procedures which address the problems in the business. Any policies and procedures will include best practice as well as specific local elements. Policies and procedures should be communicated to local management with time set aside for reflection prior to a process of discussion and amendment to ensure complete buy-in from local management before dissemination.
Train-the-trainer: Following the awareness phase and completion of policies and procedures the next stage of the programme will be to educate local senior management, health & safety and training personnel. This programme will include relevant information on the extent of sleep deprivation, the effects of fatigue (on health, safety and performance), local legislation and working standards, company policies and procedures, roles and responsibilities, how to spot the signs of fatigue, best practice in dealing with fatigue (prior to and during a shift) as well as how to raise issues with staff and management.
Education: Once senior global and / or local personnel have been educated the next phase is to roll out a comprehensive programme of education to the staff working on the ground. There will be aspects of the education programme which are generic and aspects which should be tailored to the specific audience. The delivery of the content should also be tailored to different groups. The key to engaging different staff groups is to communicate with them in way they are most comfortable. The format of the delivery should be adapted to best suit the needs of the different worker groups. These may be one or a combination of videos, emails, posters, podcasts, CDs and intranet pages.
What next?
We hope that this blog post has at least formed a basis for discussion on the issues surrounding the health, safety and performance implications of shift work.
This post is an extract form a comprehensive white paper entitled “Shift working: Exploring the health and performance implications and how you can tackle them by focusing on sleep." The paper also alludes to a number of studies to back up the points we make in respect of health and performance effects of shift working and sleep deprivation. To download a free copy of the full presentation please click here.
Tiredness and fatigue is costly, unproductive, unhealthy and unsafe. Third Pillar of Health (an IIRSM-accredited organisation) helps companies worldwide improve key business metrics through staff assessment, recommended solutions and education on tiredness and fatigue.
