Behavioural adaptation : A review of adaptation to workplace heat exposure of kitchen workers with reference to gender differences in Durban

More than a decade ago, Chapanis (2004) claimed that modern ergonomics is not robust enough to deal with many significant differences found amongst the people of the earth. Ergonomics can roughly be defined as the study of people in their working environment. The goal is to eliminate discomfort and risk of injury because of work (University of North Carolina 2021). Individual variations in humans have a huge impact on comfort and should be wisely considered in the design of a building (Zhang & De Dear 2019). This study aims to investigate the magnitude of gender differences in the environmental ergonomic parameters namely, heat, ventilation and humidity, amongst kitchen workers.


Introduction
More than a decade ago, Chapanis (2004) claimed that modern ergonomics is not robust enough to deal with many significant differences found amongst the people of the earth. Ergonomics can roughly be defined as the study of people in their working environment. The goal is to eliminate discomfort and risk of injury because of work (University of North Carolina 2021). Individual variations in humans have a huge impact on comfort and should be wisely considered in the design of a building (Zhang & De Dear 2019). This study aims to investigate the magnitude of gender differences in the environmental ergonomic parameters namely, heat, ventilation and humidity, amongst kitchen workers. and fairness, the refuge for oppressed people and victims of injustice. Yet, it accommodates gender domination and discrimination (Okoli 2019). Gender equity becomes imperative as Okeke (2011) posited that sustainable development requires the full participation of women at all levels. United Nations (2014) claimed that achieving gender equality is a central requirement of a just and sustainable world. Geneva College (2021) disseminated that restoration of the God's creation -the environment -is part of a Christian life.
This study examines that given the gender equality/ inequality status, do women kitchen workers react to kitchen environment in the same way as men? Does their well-being involve different behavioural adaptations to men? Does the discomfort level of men and women differ? Are women more vulnerable or sensitive to environmental parameters? Can the morphological differences amongst male and female workers affect heat adaptation? Do differences in the clothing typically worn by men and women affect adaptation to heat? Do make-up and hairstyles influence discomfort from heat? Earlier, Hignett (2001) criticised that there is very limited ergonomics information on female workers. Ringstaff (2021) claimed that Proverb 31 on virtuous woman is not about being perfect but finding freedom from perfection and the confidence to live life with purpose. United Nations (2017) raised critical gender concerns in the advancement of the Sustainable Development Agenda, as women propel economic growth, protect the environment and advance social development, yet half of the population is left behind. Guzik (2021) claimed that Bible does allow a woman to work outside home, however, her priorities are home, husband, and bearing and raising of children.
Women, in particular, seem to be impacted more by climate change as it affects their ability to cope with the effects of climate change on their health (Hudspeth 2016). Ruiz-Cantero et al. (2007) argued that the bias from androcentrism affects new knowledge that lacks in research and scientific literature concerning issues related to women's occupational health.

Workplace heat exposure
Owing to under-reporting of heat disorders, the possible effects of occupational thermal experience are misjudged (Xiang et al. 2014). Kitchen workers in the hospitality industry are at risk of heat stress including grillers, fryers and bakers. According to Bible Hub (2021), Samuel 8:13 described that 'The king will take your daughters from you to be confectioner, cook and bake for him'. The Wet Bulb Globe Temperature (WBGT) (ISO 7243:1989) is widely prevalent in determining the direct Heat Stress Index that incorporates heat, humidity, airflow and heat radiation (Havenith & Fiala 2011). At WBGT above 40 ºC, it is challenging to perform any physical work (Parsons 2011). Hansen et al. (2018) reported symptoms of a worker looking pale, lethargic and distraught; experiencing headaches, muscle fatigue, exhaustion and fainting.
According to De Dear, Kim and Parkinson (2018), physiological, behavioural and psychological mechanisms such as acclimatisation, behavioural and environmental changes and occupant preferences are all involved in comfort adaptation. The authors add that claims of 'adaptive opportunity' refer to how well a built environment supports occupant comfort interventions. Lerardi and Pavilonis (2020) warned about the dangers of heat-related illnesses (HRI) in a school kitchen. Continuous operation of and proximity to high heat-generating ovens and food warmers, inadequate or insufficient ventilation, a high worker density compared with the physical size of the kitchen space and a lack of adherence to a proper work/rest schedule because of constant meal demand are all factors that may contribute to levels of excessive heat stress in this setting. Simone et al. (2013) found that the interior temperature in restaurant kitchens is unacceptable and climate zone influences thermal conditions in the kitchens. Where temperatures can be raised by machines, cooking equipment and inadequate ventilation, the kitchen staff is most at risk, with dry temperatures in the kitchen exceeding 30 °C (Heinonen 1997). Increased heat in kitchens from fuels and cooking methods increase workers' risk. Zhao and Zhao (2018) added that Chinese cooking practices generate a large amount of heat. According to Fletcher (2006), there were no kitchens in the Old Testament. Food was prepared in the open in front of the tent, in city courtyards or in the shared living room. Haruyama et al. (2010) reported that heat in liquefied petroleum gas (LPG) kitchens is much higher than in electric ones. Rabeiy (2018) reported that the WBGT index can reach 31.6 °C in some bakeries, surpassing the threshold limit value of 28 °C. Gender disparities in physiological responses, as well as differences in men's and women's attire, may influence psychological responses to the moderate thermal climate encountered in everyday life (Yasuoka et al. 2015). Montazami and Lunn (2020) reported that females are more affected by poor indoor environmental quality than males. Women are more sensitive to departures from an ideal comfort setting and are more critical of the indoor thermal temperature (Zhang & De Dear 2019). Indraganti (2020) found that women in Asia are more likely to be unhappy than males with their perceptions of thermal comfort and indoor air quality; a change in the design of personal controls for women can improve their contentment with environmental factors. Lundgren and Holmér (2013) reported that climate change and global warming are exacerbating conditions in many tropical and sub-tropical areas with high temperatures and humidity. Durban has a humid sub-tropical coastal climate (Conradie 2012). According to Kjellstrom et al. (2014), during hot periods, the average temperature could rise by 2 °C to 4 °C, in most of South Africa; the occupational heat is changing from 'low risk' to 'moderate or high danger'. Gangiah and Naidoo (2021) found that more than 98% of the male workers and 99.1% of the female workers were comfortable with the climate in Durban, and 98.4% of the male workers and 99.1% of the female workers like Durban climate. Almost 38% male workers and 62.6% female workers claimed that they did not maintain a comfortable lifestyle.

Heat stress and physiology
According to Goldfarb, Seo and Sinha (2019) gender-specific variability in physiological reactions can be related to differences in men and women's brain responses to acute stressors. Females may be more susceptible to stress as a result of these gender differences (Bangasser & Wiersielis 2018). Male and female morphological differences in the ratio of body surface area to mass illustrate gender differences in heat loss thermo-effectors (Notley et al. 2017). Similarly, women may be more vulnerable to exertional heat illness (Alele et al. 2020). Lisman et al. (2014) reported that the association between gender and heat tolerance test (HTT) performance is controlled by anthropometric and fitness measurements.
Alarmingly, 42% of females were classified as heat intolerant in comparison to only 27% of males in the military.
Despite their higher fat content, females have lower skin temperatures at rest than males ), but their body temperatures are higher during physical work (Haruyama et al. 2010). This is supported by Lan et al. (2008) who reported that women in China are more susceptible to temperature than humidity compared with men. Females' comfort temperature was marginally higher (24.0 °C) than males' (23.2 °C), as per Maykot et al. (2018). In the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) comfort zone, women felt a chill and were more uncomfortable than men. Female employees, according to Sümer (2020), fared better in terms of occupational temperature tolerance.
Interestingly, women experience the same thermal climate as being slightly cooler than men (Parsons 2002). According to Alshaikh and Alhefnawi (2020) females are less sensitive to high temperatures than males. This is supported by Kumar, Jain and Mathur (2020) who found that comfort temperatures of women were around 1.5 °C higher than men's (Park, Loftness & Aziz 2018). Women are more vulnerable to the effects of cold than men (Van Hoof et al. 2017).
Males with a factor loading of 0.780 cope with the heat better than females with other individual factors, showing that gender plays a vital role in coping with the heat (Gangiah & Naidoo 2021).  implied that men cope better with radiant heat generated by grillers and ovens. According to Devlin (2017), the variation in average basic metabolic rate (BMR) (women have a lower BMR than men) and body heat production between men and women explains why males and females have different comfort temperatures (BBC News Magazine 2015). Women's higher tolerance for humid heat is a physiological adaptation that is most likely because of their lower sweat levels (Xiang et al. 2014). This suggests that female workers can cope better with moist heat in the kitchen than male staff.

Gender ratio
Globally, women do 85% to 90% of the cooking, and comprise a significant part of the workforce in the food and restaurant industry (Niethammer 2020). Amongst the fast food workers in the United States of America (US), 51.2% of them were women, whilst 43.5% were men (Zippia 2021), whereas 25.8% of women and 70.3% of men were chefs. Troitino (2020) highlighted the disheartening lack of leadership roles women hold in restaurants despite the central role they have traditionally held in kitchens. Almost 7% of restaurants in the US are led by women. The ratio of males to females was approximately 1:2 (36.3%: 63.7%) (p < 0.001) in this study. This is in concurrence with Logeswari and Mrunalini (2017) who reported that the majority of the workers in the hostel kitchens were female (75%) and only 25% were male.

Weight and body mass index
The weight of South African kitchen workers was notably higher in the range from 42 kg to 157 kg with standard deviation of 15.46 kg. A total of 64% of kitchen workers were female, and 50% of them were overweight. A total of 36% were males and 71% had normal weight. The body mass index (BMI) amongst the sampled kitchen workers varied from 18.70 (underweight) to 47.90 (severely obese) with a mean of 28.57, which indicates normal weight. In contrast, Haukka et al. (2012) reported that 15% of Finnish female kitchen workers were obese and 33% were overweight. The role of gender was further amplified in cross-tabulation between the kitchen worker's gender and BMI that was found to be statistically significant.
Guided by the definition of obesity where BMI ≥ 30 (Hillis 2018), the present study found that a minority of 29.8% of kitchen workers had normal BMI, with the remaining workers being overweight to obese. BMI in the range of 20-25 is considered normal range; important to endure physically strenuous kitchen work, which affects acclimatisation. The risk of HRI increases with excess body fat (Bedno et al. 2014).
The logistic regression reveals that gender with a β coefficient of 3.257 and variance inflation factor (VIF) = 1.209 are factors affecting BMI of a kitchen worker. The association between variables across instruments informs that gender is closely associated with other individual factors, years of employment and type of kitchen. Exploratory factor analysis (EFA) further revealed a factor loading of 0.780, 0.850 and 0.554 for gender, race and fitness with factors influencing coping with kitchen heat and was categorised into component 1, Demographics. Contrarily, less than 6% (f = 2) of head chefs strongly agreed that males cope better than females with kitchen heat.

Clothing and gender
Likewise, the importance of clothes in terms of thermal comfort cannot be overstated according to Fanger's (1970) comfort equation. Seasonal behavioural adaptation must be taken into account when assessing perceived thermal satisfaction (Park et al. 2018). Men and women's thermal discomfort is influenced by variations in clothing insulation.
During Biblical times, the commoner wore simple clothes that suited their environment and work. Both men and women wore a loose, woollen, robe-like cloak as an external apparel, secured at the waist with a band. A tunic or a coat was worn under the wrap (International Standard Bible Encyclopedia 2021). The difference between men and women's clothing was small, but distinctive. In addition, men regularly wore a turban to restrain their hair, and in some traditions, women wore a veil. However, there was a prohibition against wearing clothes woven of wool and linen together (Christian Bible Reference 2021).
Gender disparities may be attributed to variations in clothing insulation and metabolism (Park et al. 2018) with a substantial gap in thermal dissatisfaction between men and women. Hence, almost 39% of the kitchen workers in the present study were wearing a regulation T-shirt; even a house-coat for female chefs. A total of 50% of the kitchen managers claimed that staff complained with regard to humidity such as sweat not drying, wet uniforms and stickiness. In very hot periods, the human organism uses perspiration to maintain its temperature within proper physiological limits. Singh et al. (2016) reported that male kitchen workers wear aprons and head-coverings in the kitchen over casual clothes. Females in India are mostly (99%) dressed in loose-fitting Indian attire with much better scope for thermal adaptation (Indraganti, Ooka & Rijal 2015). This is totally in contrast with Lundgren-Kownacki (2018), who claimed that female workers are more prone to heat stress because of the use of clothing that inhibits heat dissipation. Females were more vulnerable to heat stress due to the practice of wearing a protective shirt over traditional clothing at work, which increases the thermal discomfort. The researcher observed that 96.5% of the food service workers in the sampled kitchens wore long pants, except for 3.5%. Golf shirts and formal shirts in kitchens were observed amongst 12% and 3.5% of kitchen workers, respectively.
The cross-tabulation between kitchen workers feeling comfortable working in chef's uniforms and the number of meals prepared in a single shift was found to be statistically significant; the two-sided p-value from Fisher's exact test was 0.045. Only one chef had a wet uniform because of excessive sweating. New et al. (2020) proposed that staff should be advised to wear comfortable clothes made of natural fibres to facilitate adaptability to thermal comfort.

Capacity for preventative behavioural control measures
Behavioural control interventions aim to diminish exhaustion, maximise endurance and enable sustained activity during the workday. McCullough (1973) found that bio-cultural adaptation behaviour amongst the Yucatan avoids heat stroke and heat cramps when working in a hot environment. Lundgren-Kownacki (2018) reported that in Chennai (India), buttermilk is commonly consumed by workers, a traditional way of mitigating heat strain.
Self-pacing and rest breaks are traditional cultural practices including napping and pacing have been useful approaches for personnel to regulate and safeguard themselves from extreme heat in the past (Brake & Bates 2002). The authors further suggest that the daytime difference in core body temperature, which is lower at nightfall, contributes to a lower risk of heat-related illness on the night shift, and therefore kitchen staff on the evening shift are exposed to lesser heat strain because of cooler evening temperatures. Goldman (2014) suggested that human evolution can be influenced by traditions and cultural practices, play a dominant role in everyday survival in hot environments. Lundgren-Kownacki et al. (2018) argued that frequent use of air conditioning will lead to humans losing their physical and mental capacity to withstand heat, increasing susceptibility to rising urban temperatures. Gangiah and Naidoo (2021) reported that only 3.5% male workers and 7.2% female workers use an air-conditioner in their residence and 11.5% male workers and 7.9% female workers drive a car to work. However, 44.3% male workers and 44.8% female workers complained that the cooling sources in their restaurant kitchens were inadequate. Around 64% females do not use make up whilst working in restaurant kitchens to improve thermal comfort.
Nonetheless, as various socioeconomic groups have different capacities for responding to growing crises, increased heat affects people unequally . Behavioural adaptations to hot weather, according to Kenny et al. (2019), also play a part in reducing a person's vulnerability to indoor heat stress.

Behavioural adaptation
Humans have developed habitat-specific cultural heat adaptations (Boyd, Richerson & Henrich 2011). Culture and genetics are becoming profoundly intertwined, with each affecting the natural progression of the other, resulting in a phenomenon known as 'gene-culture co-evolution' (Goldman 2014). As per Hellwig et al. (2020), thermosregulation may be a behavioural response because comfort/ distress perception triggers behavioural adaptation. Van Hoof et al. (2017) found that the initial step is a behavioural action followed by adjustment of thermal environments such as reducing clothing layer, rest or open windows. Other adjustments include minimising physical activity, remaining indoors, wearing light, cool clothing, increasing liquid intake and utilising an air conditioner.
Behavioural modification amongst people of lower socioeconomic status is moderated by their living conditions, their sub-standard housing with insufficient ventilation and air-conditioning (Hansen et al. 2013), and as these workers cannot cool their bodies adequately at night, they are at an increased risk (Frimpong 2015). Environmental changes that cause irregular events, long durations or a lack of cooling at night, according to Sheridan and Dixon (2017), may alter the nature of heat impacts. Schweiker et al. (2017) are convinced that behavioural adaptation is relevant in both mechanically and non-mechanically cooled workspaces.
Reactive behavioural adjustment to heat adaptation dominates studies seeking improvement in conditions that impact heat illness (Figure 1). Whilst there are proactive practices for human heat adaptation in the workplace, it is sparsely mentioned in literature. However, Bates and Schneider (2008) observed mandatory hydration and thermal work limits in the workplace, a condition imposed on kitchen workers would suitably assist in keeping their well-being. A working knowledge of hydration and selfpacing assists in the effective assessment of thermal work limit (Kapanowski 2018).
Two findings strongly support preventative dehydration out of the seven reactive behavioural adjustment studies analysed in this study (Table 1). Preventative dehydration seeks to replace water timeously. Drinking cold water clearly advances the cooling of the body and prevents dehydration (Logeswari & Mrunalini 2017;Totsky 2006). The authors further emphasise worker acclimatisation to heat and the use of appropriate clothing to ensure thermal comfort. Totsky (2006) and Matsuzuki et al. (2011) proposed pacing and rest to decrease thermal discomfort.
Drinking large amounts of water can cause frequent urination, necessitating adequate toilet facilities for employees (Biggs, Paterson & Maunder 2011). Kitchen workers are often more likely to skip regular toilet visits for the reasons mentioned above, as well as for hygiene reasons, resulting in dehydration. This is likely to increase heat strain amongst cooks, bakers and dishwashers.
Opening windows where feasible, improving air circulation by using fans, installing sufficient extractors for fumes and gases, air-conditioning work areas and restrooms to reduce ambient temperature and thermal load on workers as shown in Table 1 are some of the modifications when affected at work areas can help minimise heat (Unison 2014). Behavioural modifications include cooking on back burners that further removes cooking emissions, so it should always be used first, effectively reducing humidity (Singer & Stratton 2014).
To efficiently treat heat-related illness, some authors suggest educational initiatives and worker awareness (Table 1). Haruyama et al. (2010) discovered that heat stress could be minimised in work areas with high heat and humidity, such as commercial kitchens, by simply maintaining dry floors. Researchers in the US and China have created a heat-rejecting film that can reflect up to 70% of the heat emitted by sunlight in a building's windows (Chu 2018). This film, which is embedded with tiny thermochromic particles, can be used to cover exterior-facing windows to cut air-conditioning costs by 10%. To minimise heat in kitchens, kitchen windows can be covered with film.
In their analysis, Gangiah and Naidoo (2021) discovered that all kitchens had cooling devices in addition to extractors to minimise humid heat. Fewer air conditioners and industrial fans were identified by significantly more respondents (p 0.05). Head chefs and kitchen managers claim to have cleaned the extractors (44%) to minimise humidity in kitchens, whilst 41% say humidity is not a problem. To reduce humidity, nearly  Gangiah and Naidoo (2021) account for kitchen workers who stand near the air-conditioner or fan; step out of the kitchen, move to the back door where airflow helps cope with stuffiness and heat and take a short break. The most common behavioural adaptation by workers was to drink cold liquid (94%). Behavioural modification to cope with humidity includes the use of fans and air-conditioners by kitchen workers. A total of 35% of head chefs reported that 8.8% of workers took a short break or stepped outside to get respite from the heat. A total of 47% of head chefs strongly agreed that work experience played a strong role in coping with the heat, followed by race (37.5%). Fitness and body weight were also considered important with 20.6% and 14.7% of head chefs, respectively.
Other strategies used by kitchen workers included going towards a cooler, sitting near the cooler, putting head inside the chiller, keeping the back door open and pouring water on their heads. Kumar et al. (2020) reported that students indulge in interactive adaptation such as opening windows, doors, fans, changing their activity to rest or take a break from work. Students further drink hot or cold beverages, move to some airy place or walk indoors or outdoors to make themselves comfortable during uncomfortable conditions.
These behaviours resonate with a study by Indraganti et al. (2015) that office workers adapt to summer and monsoon (humid) conditions by staying in airy places, drinking cold/ hot beverages, and changing their posture. Occupants also avoid direct sunlight, rest, rinse their face and hands and avoid heat sources. Workers' fluid and electrolyte supplementation, long rest breaks and sitting under fans are all listed by Balakrishnan et al. (2010). If the workplace is not dangerously hot, Ballman (2012) suggested that using fans, drinking plenty of water and putting a cool wet cloth on the forehead periodically will help cope with heat stress. Several chefs claimed that in Norwich, cool baby wipes are used to wipe heads. Drinking plenty of water helps to get through the heat as the temperature at a bakery can reach 37.8 °C.
To quench their thirst, nearly a quarter of the workers, who were studied, rendered cold lemonade. There is no clear legislation about humidity, according to the University of Birmingham Health and Safety Fact File (2006). Workers are allowed to take extra breaks, are provided with cold drinks or the dress code could be relaxed. Even if the temperature is high, health and safety measures, such as wearing the appropriate protective personal equipment, must not be overlooked. Kitchens with induction cooktops provide greater comfort to chefs than those with LPG cooktops (Wong et al. 2011). Relevant behaviours and activities may also be targeted by education and by creating awareness (World Health Organization 2020).

Prospective designs to improve conditions that impact heat illness
Creating a win-win situation for workers' health and work performance is the way forward. On the one hand, workers' health is at risk, and on the other hand, the researcher believes that there is no clear provision in South African legislation for employees to reduce risk exposure. In the US, a countrywide awareness educates workers and employers about the dangers of working in the heat and preventing illness (National Institute of Occupational Safety and Health [NIOSH] 2015).
The pursuance of protocols of the hospitality sector to protect workers from the heat exposure has compelled some of the foregoing choices in design and management. This inertia could be attributable to policy gaps or simply the failure of management to plan for long term. Regrettably, the researcher feels that collective responsibility for safety and human health foster vague duty for individual action. When it comes to safeguarding people from high heat, investigators, representatives, state and city council members and officials, all must be vigilant (Sheridan & Dixon 2017).

Conclusion
This article conducts a comprehensive analysis of the literature on the various behavioural adaptation mechanisms used by kitchen staff to cope with heat exposure at work. The discomfort levels of men and women vary as women are more sensitive to dry heat and cold. Clothing worn by women, their make-up and hairstyles influence discomfort from heat, highlighting ergonomics data on female workers. Comparative studies have not been performed to establish which behavioural measure is superior to others. It is clearly observable that kitchen workers were provided with inadequate measures to reduce heat strain.