Introduction: In this study we (i) introduced time-motion analysis for assessing the impact of workplace heat on the work shift time spent doing labor (WTL) of grape-picking workers, (ii) examined whether seasonal environmental differences can influence their WTL, and (iii) investigated whether their WTL can be assessed by monitoring productivity or the vineyard manager's estimate of WTL. Methods: Seven grape-picking workers were assessed during the summer and/or autumn via video throughout four work shifts. Results: Air temperature (26.8 ± 4.8°C), wet bulb globe temperature (WBGT; 25.2 ± 4.1°C), universal thermal climate index (UTCI; 35.2 ± 6.7°C), and solar radiation (719.1 ± 187.5 W/m2) were associated with changes in mean skin temperature (1.7 ± 1.8°C) (p < 0.05). Time-motion analysis showed that 12.4% (summer 15.3% vs. autumn 10.0%; p < 0.001) of total work shift time was spent on irregular breaks (WTB). There was a 0.8%, 0.8%, 0.6%, and 2.1% increase in hourly WTB for every degree Celsius increase in temperature, WBGT, UTCI, and mean skin temperature, respectively (p < 0.01). Seasonal changes in UTCI explained 64.0% of the seasonal changes in WTL (p = 0.017). Productivity explained 36.6% of the variance in WTL (p < 0.001), while the vineyard manager's WTL estimate was too optimistic (p < 0.001) and explained only 2.8% of the variance in the true WTL (p = 0.456). Conclusion: Time-motion analysis accurately assesses WTL, evaluating every second spent by each worker during every work shift. The studied grape-picking workers experienced increased workplace heat, leading to significant labor loss. Monitoring productivity or the vineyard manager's estimate of each worker's WTL did not completely reflect the true WTL in these grape-picking workers.

Climate change is expected to exacerbate heat stress at the workplace in temperate regions, such as Slovenia. It is therefore of paramount importance to study present and future summer heat conditions and analyze the impact of heat on workers. A set of climate indices based on summer mean (Tmean) and maximum (Tmax) air temperatures, such as the number of hot days (HD: Tmax above 30 °C), and Wet Bulb Globe Temperature (WBGT) were used to account for heat conditions in Slovenia at six locations in the period 1981–2010. Observed trends (1961–2011) of Tmean and Tmax in July were positive, being larger in the eastern part of the country. Climate change projections showed an increase up to 4.5 °C for mean temperature and 35 days for HD by the end of the twenty-first century under the high emission scenario. The increase in WBGT was smaller, although sufficiently high to increase the frequency of days with a high risk of heat stress up to an average of a third of the summer days. A case study performed at a Slovenian automobile parts manufacturing plant revealed non-optimal working conditions during summer 2016 (WBGT mainly between 20 and 25 °C). A survey conducted on 400 workers revealed that 96% perceived the temperature conditions as unsuitable, and 56% experienced headaches and fatigue. Given these conditions and climate change projections, the escalating problem of heat is worrisome. The European Commission initiated a program of research within the Horizon 2020 program to develop a heat warning system for European workers and employers, which will incorporate case-specific solutions to mitigate heat stress.Electronic supplementary materialThe online version of this article (10.1007/s00484-018-1530-6) contains supplementary material, which is available to authorized users.

Changing patterns of heat waves are part of the global warming effect and the importance of changes is reinforced by their negative impact on society. Firstly, heat waves were analyzed in Brnik (Slovenia) and Larisa (Greece) in the period 1981–2017 to reflect the environment which workers are exposed to. Secondly, outdoor workers (70 from Greece, 216 from Slovenia) provided a self-assessment of heat stress. The heat wave timeline is presented as an effective way of illustrating long-term changes in heat waves’ characteristics for various stakeholders. In both countries, workers assessed as significant the heat stress impact on productivity (Greece 69%, Slovenia 71%; p > 0.05), and in Slovenia also on well-being (74%; p < 0.01). The main experienced symptoms and diseases were thirst (Greece 70%, Slovenia 82%; p = 0.03), excessive sweating (67%, 85%; p = 0.01), exhaustion (51%, 62%; p > 0.05) and headache (44%, 53%; p > 0.05). The most common way to reduce heat stress was drinking more water (Greece 64%, Slovenia 82%; p = 0.001). Among the informed workers, the prevalent source of information was discussions. Therefore, educational campaigns are recommended, together with the testing of the efficiency of mitigation measures that will be proposed on the Heat-Shield project portal.

Climate changes and the associated higher frequency of heat waves in Middle-European countries will aggravate occupational heat stress experienced by Slovenian workers. Appropriate behavioral adaptations are important coping strategies and it is pertinent to establish if knowledge among advisers and workers is sufficient and identify the symptoms experienced by workers. Therefore a survey including 230 farmers and 86 agricultural advisers was completed. Thermal comfort ranged from hot to extremely hot for 85 ± 5 % of farmers working outside and heat stress had a negative impact on well-being (74 ± 6 %), productivity (68 ± 6 %) and concentration (34 ± 6 %). Reported symptoms were excessive sweating (84 ± 5 %), thirst (81 ± 5 %), and tiredness (59 ± 6 %). Women had a higher prevalence of headache (64 ± 10 %) compared to males (47 ± 8 %), higher frequency of fatigue (69 ± 10 vs 56 ± 8 %), and incidents with nausea or vomiting (19 ± 8 vs 9 ± 5 %). 81 ± 4 % of the responders reported that more time is required to complete tasks when the weather is hot. Nevertheless, 61 ± 6 % of farmers have never been informed of the impacts of heat stress and 29 ± 10 % of the agricultural advisers does not include this information in their guidance. This emphasizes the need for increased information and implementation of feasible solutions to mitigate the negative impact of heat stress on workers in the agricultural sector.Key words: heat stress; labor; farmers; agricultural advisers; health; well-being IZVLEČEK POZNAVANJE VROČINSKEGA STRESA NA DELOVNEM MESTU MED KMETIJSKIMI SVETOVALCI IN DELAVCI V SLOVENIJIV Sloveniji temperatura zraka narašča bolj kot v Evropi, zato je pomembno oceniti vplive vročinskega stresa na delovne razmere, sploh pri zunanjih delavcih, kot so kmetje. Raziskava je bila izvedena med 230 kmeti in 86 kmetijskimi svetovalci. Toplotno udobje je že zdaj neprimerno (vroče, prevroče ali zelo prevroče) za 85 ± 5 % kmetov, ko delajo zunaj, pri čemer vročinski stres vpliva na počutje (74 ± 6 %), storilnost (68 ± 6 %) in zbranost (34 ± 6 %) kmetov. Osnovni zaznani simptomi vročinskega stresa so povečano potenje (84 ± 5 %), žeja (81 ± 5 %) in utrujenost (59 ± 6 %). Ženske statistično značilno v večjem deležu poročajo o glavobolih (64 ± 10 % žensk in 47 ± 8 % moških), izčrpanosti (69 ± 10 in 56 ± 8 %) in slabosti oz. bruhanju (19 ± 8 in 9 ± 5 %). Kmetje in svetovalci skupno v več kot 80 % (81 ± 4 %) navajajo, da kmetje v času vročinskih valov za isto delo potrebujejo več časa. Kljub temu 61 ± 6 % kmetov še nikoli ni bilo obveščenih o vplivih vročinskega stresa, 29 ± 10 % svetovalcev pa še nikoli ni svetovalo o tem. Zelo jasno se kaže potreba po pripravi uporabnih, ne preveč splošnih smernic in možnih rešitev za zmanjšanje negativnega vpliva vročinskega stresa na kmete.

Occupational heat strain is a public health threat, and for outdoor industries there is a direct influence from elevated environmental temperatures during heat waves. However, the impact in indoor settings is more complex as industrial heat production and building architecture become factors of importance. Therefore, this study evaluated effects of heat waves on manufacturing productivity. Production halls in a manufacturing company were instrumented with 33 dataloggers to track air temperature and humidity. In addition, outdoor thermal conditions collected from a weather station next to the factory and daily productivity evaluated as overall equipment efficiency (OEE) were obtained, with interaction between productivity and thermal conditions analyzed before, during, and after four documented heat waves (average daily air temperature above 24°C on at least three consecutive days). Outdoor (before: 21.3° ± 4.6°C, during: 25.5° ± 4.3°C, and after: 19.8° ± 3.8°C) and indoor air temperatures (before: 30.4° ± 1.3°C, during: 32.8° ± 1.4°C, and after: 30.1° ± 1.4°C) were significantly elevated during the heat waves (p &lt; 0.05). OEE was not different during the heat waves when compared with control, pre-heat-wave, and post-heat-wave OEE. Reduced OEE was observed in 3-day periods following the second and fourth heat wave (p &lt; 0.05). Indoor workers in settings with high industrial heat production are exposed to a significant thermal stress that may increase during heat waves, but the impact on productivity cannot be directly derived from outdoor factors. The significant decline in productivity immediately following two of the documented heat waves could relate to a cumulative effect of the thermal strain experienced during work combined with high heat stress in the recovery time between work shifts.