Workload and associated factors: a study in maritime port in Brazil 1

ABSTRACT Objective: to identify the effect of the mental, physical, temporal, performance, total effort and frustration demands in the overall workload, and in the same way analyze the global burden of port labor and associated factors that contribute most to their decrease or increase. Method: a cross-sectional, quantitative study, developed with 232 dock workers. For data collection, a structured questionnaire with descriptive, occupational, smoking and illicit drug use variables was applied, as well as variables on the load on the tasks undertaken at work, based on the questionnaire NASA Task Load Index. For data analysis, we used the analysis of the Poisson regression model. Results: the demands physical demand and total effort showed greater effect on the overall workload, indicating high overall load on port work (134 employees - 58.8%). The following remained associated statistically with high levels of workload: age (p = 0.044), to be employee of the wharfage (p = 0.006), work only at night (p = 0.025), smoking (p = 0.037) and use of illegal drugs (p = 0.029). Conclusion: the workload in this type of activity was high, and the professional category and work shift the factors that contributed to the increase, while the age proved to be a factor associated with a decrease.

the demand for mental demand and frustration at work, workload components, are the largest and are related to emotional problems (7) . In addition, study conducted with longshoremen -dock worker category -run by psychologists, pointed mental and physical workload of these workers, identifying, beyond the physical issue of the work in the port, the mental issue, in relation to the demand of attention and concentration at work (8) .
The population of dock workers focus of this study is exposed to inadequate working conditions, related to the degree of workload, from the type of activity. Port work involves loading procedures, unloading, transport and storage of goods (9) , such as container movement (garments, meat and computers), liquids (oils and fuels), solids (grain, coal and cement), fractionated products (paper, wood, steel rollers and wind turbines) and roll on/roll off (Cars, buses, trucks, agricultural vehicles and cranes) (10) . This activity is responsible for providing products to all over the world, demonstrating its global importance (11) . On the other hand, it presents stressful and dangerous conditions to workers directly involved in this process.
It may be reiterated that the dock workers deal with processes and very specific products, for example fuels. A study conducted in the US showed that benzene exposure occurs mainly in short-term tasks such as the removal of the fuel tank sampling and disconnecting hoses for the handling of goods (12) . The human effort needed to develop numerous tasks involved in port activities, is opposed to the advancement of technological products that are moved by them, i.e. working conditions that still require qualitative and quantitative improvements so that the total effort imposed on the human strength in the port work is minimized. In this perspective, the study of the workload to which dock workers are exposed contributes to the advancement of knowledge of how costly is the port activity for the health conditions of workers.
Furthermore, this study is relevant because, relative to the workload of the port environment, there is only one study that supports such knowledge in the literature (8) . This study was conducted in Brazil, which Cezar-Vaz MR, Bonow CA, Almeida MCV, Sant'Anna CF, Cardoso LS.
shows a gap in scientific knowledge and its circulation in the international context. Furthermore, it addresses longshoremen, only one of among many other categories of dock workers. These characteristics demonstrate the lack of knowledge about this specific population, due to the characteristics of the port work and possible damage to the health of this worker.
Another situation that demonstrates the importance of the study is the possibility to identify workload components that have more effect on the overall workload. In this direction, aimed to identify the effect of the mental, physical, temporal, performance, total effort and frustration demands in the overall workload, just to analyze the global burden of port labor and associated factors that contribute most to their decrease or increase. This research was made up of foremen, longshoremen and cargo checkers. The work of wharfage involves goods movement activities within the port, longshoremen are responsible for the movement of goods on the decks or in the basements of ships and cargo conferees act both within the vessels and the port facilities, making the verification of the goods (13) .

Method
The subjects were interviewed in the workplace, i.e. a seaport area in southern Brazil, in the period from January to November 2014.
For data collection, individual interviews were used, conducted using a structured questionnaire, which presented socio-demographic variables (gender, age, ethnicity -information reported by participants, marital status and education), occupational variables (port occupation, monthly income, working time and shift), dichotomous variables related to the use of tobacco and illicit drugs (without specifying the type used for this study).
These variables, mentioned, were tested in previous research (14)(15) and adapted for the current study. To identify the workload in the tasks we applied a validated scale, the NASA Task Load Index (NASA-TLX) (1) , which features six demands for measuring workload: mental demand (a task performed has a lot of mental activity, such as decision and calculation), physical demands (the job requires physical activity such as push, pull and control), temporal requirement (how long is required, and even if the pace of work is slow or fast), performance (how successful the employee believes are the activities that the function requires), total effort (mental and physical trouble that the employee has to achieve the level of performance) and frustration (feeling of insecurity, depression, irritation that work can cause). This scale was chosen to measure the workload because it is validated in its conceptual and operational structures, and is one of the most used for this purpose (16)(17) .
The variables of the structured questionnaire  (1) . Although the questionnaire for verification is subjective, it is widely used (2,4,7,18) , demonstrating that it is valid and reliable to measure the workload through the overall workload and the different demands that compose it.
To determine high and low levels of port workload, the overall workload values above and below the third tertile (70%) were considered. This strategy was used in another study (19) , in which there was no predetermined cutoff point. However, although there was a cutoff point determined for the load (50%) (1) , it is understood than using above and below the third tertile (70%) facilitates www.eerp.usp.br/rlae Rev. Latino-Am. Enfermagem 2016;24:e2837 the distinction between participants who have low and high workloads. Thus, it was considered high level in the overall workload, the tasks developed in the port work if the assigned score was higher than 70 on a scale of zero to 100, corresponding to at least 70% of the highest burden.

Results
The study enrolled 232 dock workers. All  However, by means of standardized size effect, the influence was moderate for frustration level and great for the other demands. The demands with the greatest effect on the global burden were respectively, physical demand and total stress level (Table 1).  Table 2.
There was a significant association of elevated workload    Table 3).
controlling. On the other hand the total effort demand indicates the mental and physical difficulty that the worker faces to reach the level of performance that the activity requires (1). The physical demand is then doubly placed, due to the association of the total physical and mental strain requirements.
In this direction, the physical request of the port work is shown in a study on the constitution of the male working class in labor schemes in private schemes, through the concept of the dock workers as a blue-collar worker, or a worker who performs handwork and requires physical strength to carry out their activities (20) . Studies on the workload in the textile industry (4) and teachers (7) show that age has no significant relevance in the increase / decrease of the overall workload. However, a study in which age was the main factor associated (18) , shows that the worst demand workload is mental, identified by younger workers in a railway company.
Because of these results, it defends the idea that there is a need to understand the relationships and workloads at all ages, but it is necessary to pay attention to young people, because of the lack of social support (18) for this age group.
Another important point in the results, is one in which workers who perform wharfage activities showed an increase in the prevalence of high levels of workload by 69%. The wharfage workers perform tasks involving the movement of goods in facilities within the port, including receiving, internal transport, opening packages for customs inspection, handling, storage, delivery, loading and unloading of vessels (13) .
What differs from the professional activity of the wharfage from those of other dock workers interviewed (longshoremen and checkers) is that the former perform movement of goods on the decks or in the storage of other categories of workers, such as those in the textile industry (4) and rail workers (6) . This is because shift workers are prone to sleep deprivation, misalignment of circadian rhythms, drowsiness and performance deficits related to sleep, which explains the increase in the overall workload for these workers.
Workers that smoke and workers who used illicit drugs had a prevalence of 26 to 30% higher in increasing overall workload, respectively. This association can occur due to the high overall workload to which dock workers are exposed. Study of different categories (health workers) showed that one of the ways of reducing the use of drugs such as tobacco and psychoactive substances, could be to reduce the workload, demonstrating that the drug issue should be addressed in the workplace (27) .
The results of this research instigates further study the specificity the relation between lifestyle, wellness in / work and productivity.
The overall workload of dock workers showed to be high, considering that the majority (58.8%) awarded a grade higher than 70 on the scale of zero to 100.
This empirical reality, originated from the concept of global burden of work allowed to introduce a subjective analysis in the objective relation of labor productivity.
This characteristic of the workload metrics enables the nature of the dialogue between workers to be addressed with a focus on health without however leaving the stress on productivity.
The workers of this research consider their work directly in relation to productivity and when using language that keeps this nature, it allows him to grasp (subjectivity) that the workload results in organic wear and tear, with potential for disorders and diseases, and as a consequence, reduced productivity (8,26) .
When doing the interview with the workers and leading them to reflect on the global burden and its consequences, they allowed themselves to this reflect on this approach, leading to promising and ambitious future for academics jointly investing in application of technological intervention with the participation of workers and managers.
It is understood that the study has limitations with respect to the sample, represented by only one seaport, which does not allow generalization. In addition, the cross-sectional study does not verify the causes of the

Conclusion
The port workload was found to be high, being the professional category and shift the factors contributing to to its increase, while the age factor was associated with a decrease. Both the characteristics of individuals and the work can influence the port workload. This research alerts for managers and health professionals -among them, nurses -on the high workload to which dock workers are subjected; in their own work language: productivity -and the cost of production, i.e. the workload.