Alters- und geschlechtsdifferenzierte Objektivierung von Belastung und Beanspruchung bei berufsbedingten Kälteexpositionen unter Berücksichtigung eines variablen Arbeitszeit-Pausenzeit-Regimes

The sales figures of both chilled and frozen food have been rising steadily over the past decades, thus leading to an increase in the number of jobs in this sector and a growing demand of capable employees in the coming years. To satisfy the great demand, the workplace of order-pickers employed in cold-storage depots must exhibit a design which ensures that work can be carried out in the long-term regardless of age and gender. Since the superposition of the cold climate and the high physical workload results in elevated stress and strain for the human organism and therefore may pose a significant health risk.
In order to objectify cold-induced strain, 30 female subjects (Ss) of two age groups (15 females, aged between 20 and 35 and 40 and 65 years, respectively) had to carry out whole working day tasks in a cold-storage depot with a chill room (~ +3°C) and a cold store (~ -24°C). For three days, the Ss had to work under predetermined, realistic working conditions with variable working and break times. Simultaneously, the work physiologically relevant parameters such as “body core temperature”, “skin temperature”, “heart rate”, “blood pressure” and “energy expenditure” were measured. Additionally, the Ss were asked to evaluate their subjective experiences while working in the cold. To identify whether besides possible age-related differences any gender-related differences do exist, the findings were also compared with those from a former field-study under identical conditions with 30 male Ss in the same age groups.
Working in the chill room (+3°C) caused relatively moderate physiological strain reactions and showed no significant differences between the younger and older or male and female Ss. Also the cold protective clothing – with the exception of the gloves – appears to protect sufficiently, as does a warming-up break of 20 minutes.
Working in the cold store at approx. -24°C caused considerably higher strain reactions. The older Ss showed the greatest decline in body-core temperature with a maximum drop of 1.5 K compared to 1.3 K (younger Ss). Within both age groups, a
20 minute warming-up phase proved insufficient. It took subjects close to 30 minutes to reach their nature levels recorded at the outset. Regardless of age, the skin temperature both at the nose and the fingertip decreased considerably in the cold. During the warming-up breaks the decline was compensated quickly. The temperature profile of the toes showed a slightly smaller, yet continuous decrease, with a significant difference between both age groups with lower values for the older Ss. Similar to the results from the chill room, the younger Ss revealed substantially higher work pulses during all three working phases. Taking into consideration individual resting levels and the fact that the maximum heart rate of a human being will be reduced every year, the degree of the capacity utilization on average is approx. 60% for both age groups. The overall higher blood pressure of the older Ss is in accordance with the values determined at home prior to the test series. The gender-related analysis revealed a higher decrease of the core temperature for the males of both age groups, which complies with the findings of the calculated relative heat production with the highest values for the younger female Ss and the lowest values for the older male Ss. Continuous monitoring gave evidence for a comparatively higher skin surface temperature for the female Ss as well. The work pulses of the younger female Ss were clearly higher than those of the male Ss of the same age group, whereas the older male and female Ss showed almost identical values. This may be caused by the high physical capacity of the cardiovascular system of the older female Ss. Blood pressure proved to be higher for men than women. To a large extent, the objectively measured data have been confirmed by the questionnaire.
The results from the field-study show that order-picking in deep cold leads to high physical stress and strain with no distinct gender- or age-related disadvantages. In fact, promoting health on both individual as well as operational levels supports the working ability of employees. As indicated by the results from the third test series with varied working and resting times, an optimization of the length of working and break times is mandatory. As the cold protective clothing does not provide an adequately entire protection against cold, there is need for improvements of the coldinsulating boots and gloves. These adjustments may not only create preventive occupational health and safety but ultimately, should increase the efficiency of the work process for every individual.