Risks from heat kick in earlier than previously thought

In a study relevant to Australian employers, US researchers have shown that workers' bodies can quickly heat up during hot days, contrary to the common belief among employers that workers are safe from heat risks in the morning.

The collaborative study between the researchers from Emory University and the Farmworkers Association of Florida also identified risk factors leading to workers surpassing safe core body temperature thresholds, which need to be addressed in heat policies.

The team monitored the core temperatures of 221 agricultural workers over three working days with a mean heat index (combining air temperature and relative humidity) of 32 degrees Celsius. They found that each day half the workers surpassed the government-recommended core temperature limit of 38 degrees, where heat exhaustion begins. Workers exceeded this threshold well before the hottest part of the day: five per cent by 8am and most by 10.38am. Many workers' core body temperatures exceeded 38.5 degrees by 11.10am.

"These results have occupational health significance because morning hours are considered to be the safest for workers and supervisors have been observed to cease work in afternoons of very hot days," the researchers say. The risk of heat strain and heat-related illness can occur earlier in the day than expected. Heat control measures, such as rest and shade, need to be implemented at the beginning of the working day and applied consistently, not solely in the afternoon, though by this time the heat strain peaked and remained consistently high.

US Occupational Safety and Health Administration recommendations are that employers prevent heat illness through: frequent scheduled breaks in cool, shaded areas; reminders to rehydrate; reviewing key heat-related illness information in consultation with workers; and buddy system policies where workers look for signs of heat-related illness in their colleagues.

"For those working in the direct sun, OSHA recommends that employers monitor workers very closely for signs and symptoms of heat-related illness and to design schedules for work and rest intervals," the researchers add.  They also found the risk of surpassing the core temperature threshold was higher in less experienced workers, indicating new workers should be monitored more closely in hot weather. 
Read more: Valerie Mac, et al, Risk Factors for Reaching Core Body Temperature Thresholds in Florida Agricultural Workers. [Open access - pdf can be downloaded from this page] Journal of Occupational and Environmental Medicine, online first January 2021, doi: 10.1097/JOM.0000000000002150. Source: OHSAlert

Being ignored, bullying increases insomnia

Anti-bullying measures in workplaces can prevent insomnia and related hazardous symptoms in workers, according to researchers, who also investigated whether sleep problems can lead to bullying.

In a study of over 1,000 workers, Norwegian researchers from the National Institute of Occupational Health found being exposed to direct and indirect negative behaviours, like being ignored or excluded, being constantly reminded of mistakes or being denied information, were significantly associated with increased insomnia symptoms at a six-month follow up.

There is emerging evidence that exposure to workplace bullying is a key risk factor for the development of sleep problems.  A recent systematic review and meta-analysis found bullied workers are 2.3 times more likely to report sleep problems than other workers.

"Being exposed to bullying typically challenges the world view of those targeted, particularly in early phases where acts tend to be rather subtle and discrete, and may, therefore, easily lead to worries and rumination," said the study’s lead, Morten Nielsen.

Repetitive thoughts about negative work experiences and being unable to switch off from these thoughts are risk factors for sleep problems, as increasing arousal and physical activation and disturbing sleep patterns.  A number of studies show exposure to bullying is associated with symptoms of post-traumatic stress, which is characterised by hyperarousal, nightmares, and other sleep difficulties.

The researchers said, "The findings of the present study indicate that measures against bullying at the workplace can be beneficial concerning reducing sleep problems among employees." The research team points to previous research showing organisational support and an ethical climate can reduce the impacts of bullying, including another study led by Nielsen.
Read more: Morten Nielsen, et al, Associations between exposure to workplace bullying and insomnia: a cross-lagged prospective study of causal directions. [Open access] International Archives of Occupational and Environmental Health, online first February 2021, doi: 0.1007/s00420-020-01618-2.
Source: OHSAlert

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