A coffee and catnap keep you sharp on the nightshift
August 28, 2020
Science Daily/University of South Australia
A simple coffee and a quick catnap could be the cure for staying alert on the nightshift as new research from the University of South Australia shows that this unlikely combination can improve attention and reduce sleep inertia.
In Australia, more than 1.4 million people are employed in shift work, with more than 200,000 regularly working night or evening shifts.
Lead researcher, Dr Stephanie Centofanti from UniSA Online and the Sleep and Chronobiology Laboratory at UniSA says the finding could help counteract the kind of sleep inertia that is experienced by many shiftworkers.
"Shift workers are often chronically sleep-deprived because they have disrupted and irregular sleep patterns," Dr Centofanti says.
"As a result, they commonly use a range of strategies to try to boost their alertness while on the nightshift, and these can include taking power naps and drinking coffee -- yet it's important to understand that there are disadvantages for both.
"Many workers nap during a night shift because they get so tired. But the downside is that they can experience 'sleep inertia' -- that grogginess you have just after you wake up -- and this can impair their performance and mood for up to an hour after their nap.
"Caffeine is also used by many people to stay awake and alert. But again, if you have too much coffee it can harm your overall sleep and health. And, if you use it to perk you up after a nap, it can take a good 20-30 minutes to kick in, so there's a significant time delay before you feel the desired effect.
"A 'caffeine-nap' (or 'caff-nap') could be a viable alternative -- by drinking a coffee before taking a nap, shiftworkers can gain the benefits of a 20-30-minute nap then the perk of the caffeine when they wake. It's a win-win."
The small pilot study tested the impact of 200 mg of caffeine (equivalent to 1-2 regular cups of coffee) consumed by participants just before a 3.30am 30-minute nap, comparing results with a group that took a placebo.
Participants taking a 'caffeine-nap' showed marked improvements in both performance and alertness, indicating the potential of a 'caffeine-nap' to counteract sleep grogginess.
Dr Centofanti says this shows a promising fatigue countermeasure for shift workers. She says the next move is to test the new finding on more people.
https://www.sciencedaily.com/releases/2020/08/200828115401.htm
Moving light-dark exposure could reduce disruption faced by night shift workers
March 27, 2018
Science Daily/The Physiological Society
New research shows that our brain clock can be shifted by light exposure, potentially to align it with night shift patterns. It highlights that a 'one size fits all' approach to managing sleep disruption in shift workers may not be appropriate. A personalized approach, with light-dark exposure scheduled and taking into account whether someone is a 'morning' or 'evening' person, could reduce shift workers' risk of health problems.
Our sleep-wake cycle, in part controlled by our brain clock, encompasses physical, mental and behavioural changes that follow a daily cycle. Light is the dominant environmental time cue which results in, for example, sleeping at night and being awake during the day.
Night time shift work disrupts the normal sleep-wake cycle and our internal circadian (24-hour) rhythms, and has been associated with significant health problems, such as a higher risk of heart disease and cancer. Alertness levels are often markedly impaired while working night shifts.
While it has been known that there are considerable differences in how the brain clock of different individuals responds to changing shift cycles, we have known very little about the mechanisms that underlie these differences between people. If someone was able to realign their brain clock to their shift pattern, then it would improve sleep and could lead to health benefits. While such realignment is rare, in some circumstances such as on offshore oil rig platforms, complete adaption has been observed.
This new research aims to understand the relationship between light exposure and how an individual's circadian rhythm is affected across a transition from day to night shift schedules. The researchers found that timing of light exposure is the primary factor in determining how the brain clock responds to night shift work, accounting for 71% of the variability in timing of the clock observed in the study. It also found that the extent to which an individual is a 'morning' or 'evening' type affects how the body responds, which shows that a personalised approach is important.
This study was led by the CRC for Alertness, Safety and Productivity and saw nursing and medical staff recruited from an Intensive Care Unit at a major hospital in Melbourne, Australia. Staff members were enrolled into the study when working a schedule of day or evening shifts, or days off, followed by at least 3 or 4 consecutive night shifts.
To examine how the sleep-wake cycle responds to the shift schedule, the timing of the brain clock was measured on the day schedule, and at the end of the night shifts. It was measured by monitoring urinary concentration of the major metabolite of melatonin, which is a hormone produced in the pineal gland known to be involved in the regulation of sleep cycles. Individual light exposure was measured using wrist actigraphs, worn for the duration of the study.
Prof Shantha Rajaratnam, from Monash University and the CRC for Alertness, Safety and Productivity, corresponding author for the study, said:
"We know that night time shift workers are more likely to suffer health problems due to disruption of their circadian clock, and the mismatch between the timing of the clock and their sleep-wake cycle. This research is important because if we can realign a person's clock to fit their shift pattern, then they will sleep better and this may result in improved health, safety and productivity.
"These results will drive development of personalised approaches to improve sleep-wake cycles of shift workers and other vulnerable people, and could potentially reduce the increased risk of disease due to circadian disruption."
https://www.sciencedaily.com/releases/2018/03/180327203014.htm
Urban night shift police more likely to suffer long-term job injuries
January 16, 2014
Science Daily/University at Buffalo
Police officers working the night shift are significantly more likely to suffer long-term on-the-job injuries than officers on day and afternoon shifts, according to new research.
The study found that, independent of age and gender, urban officers working nights were three times more likely than those on the day shift, and 2.2 times more likely than those on the afternoon shift, to suffer injuries resulting in leaves of more than 90 days.
"Leaves of this length suggest more serious types of injury and indicate that night shift work poses a more significant threat to the life and health of officers than previously assumed," says epidemiologist John Violanti, PhD, principle author of the study "Shift work and long-term injury among police officers," published in the current edition of the Scandinavian Journal of Work and Environmental Health.
The study assessed the association of daily shift schedules with the occurrence of injury leave and lengths of injury leave from 1994 to 2009 among a cohort of 419 officers from the City of Buffalo Police Department.
Violanti, a research scientist in the UB Department of Social and Preventive Medicine, UB School of Public Health and Health Professions, says, "The study results also point to the problems long-term injuries provoke for police managers as long injury absences put a strain on police personnel who must cover for the injured officers.
"This could lead to health problems for them, as well," says Violanti, an expert on the relationship of police officer stress to serious health risks.
A previous study by this research team found that police on night shifts suffer more on the job injuries overall than their colleagues on day and afternoon shifts, and Violanti says there are several possible explanations for the high injury rates.
"Sleep disturbance and fatigue-related impairment provoked by circadian disruption have been reported in previous studies of night shift workers," Violanti says, "and have been found to affect the kind of decision making that is required in fast-paced, ambiguous, high-risk police situations.
"Evening and night police shifts are inherently more active than day shifts, too. Not only do more crimes occur during these hours, but the calls for service are generally more hazardous and more frequent, which could result in more serious injuries," he says. Subjects were comprised of 312 men and 107 women with an average age of 43 (range 27-70 years) who had completed the Buffalo Cardio-Metabolic Occupational Police Stress Study, a cross-sectional study designed to examine associations between physiological biomarkers of stress, subclinical metabolic and vascular disease markers, lifestyle and psychosocial symptomology among police officers.
In this study, 16 years of day-to-day work records enabled researchers to take into account differences in age and gender across shifts and draw conclusions more accurately than previous research that relied heavily on self-reported data. The shifts considered were: day (8 a.m. to 4 p.m.), afternoon (4 p.m. to 11 p.m.) and night (11 p.m. to 8 a.m.). The percentages of subjects who worked predominantly on the day, afternoon, and night shifts were 41 percent, 32 percent and 27 percent, respectively. Violanti and his team followed the participants for the incidence of injuries that occurred while on duty.
Violanti says that night shift workers were younger and more likely to be male, had fewer years of work experience and were composed of a larger number of patrol officers (84 percent) than were the day shift workers. Overall 9.6% of the officers experienced a long term injury during the 16 year period. After adjustment for age and gender, long-term injury incidence rates were 3.1 times higher in night shift workers than in day shift workers and 2.2 times higher than in afternoon shift workers.
In order to prevent long-term injuries in this critical population, Violanti suggests that future research take into account some of the factors examined in this study.
"Research that integrates frequency and duration of injuries would be worthwhile, as would objective measurement, over time, of sleep duration and workload. Both would enhance our understanding of the role these factors might play in influencing the risk of police injury," he says. Violanti and his co-authors conducted a landmark 2012 study that found that police stress creates significant health risks, including more chronic disease and suicide, than in the general population.
http://www.sciencedaily.com/releases/2014/01/140116162017.htm