The Complexity of Non-work: How Anthropology Deepens Our Engagement with Heat Stress Policy

The subject of extreme heat, its manifestation in the everyday lives of affected people and upon the world of work is currently proliferating in the social sciences, of which this research network is itself an instantiation, though this proliferation is quite recent. The question of occupational heat, while now featuring several notable works of ethnography and qualitative research (Nading 2025; Oppermann et al.2017; 2020; Macktoom et al. 2024 among others), as well as cultural-historical research (Chamayou 2025; Keegan 2023; Barak 2024), is still to a large extent the premise of physiologists, ergonomists and climate scientists. While there is much to learn from papers written from quantitative and scientific perspectives on heat exposure among outdoor and informal workers, the flaw is often that the consideration of social dimensions of working in the heat are non-existent or superficial.

This is what struck me when in 2024 I began my postdoctoral project researching occupational heat stress, and reading several papers on heat exposure framed quantitatively through thermometric readings, heat stress models and indices, self-reported questionnaires, etc. These studies were often directed towards abstract models of the working body through lab-based experiments, alongside some worksite-based studies. Even among the limited worksite-based studies, I found sections where only the duration of workers' breaks was noted as a factor in continued heat exposure, but the treatment of breaks was confined to the observational (for example, in Crowe et al. 2013; Nag et al. 2013). No account was made of what workers did during the break hours as if work breaks were only a matter of pausing work and recovering the body. This superficial treatment of rest is at odds with how workplace rest is a prominent workplace heat intervention: the proportion of rest time to working hours in different conditions of heat is the key recommendation of the Threshold-level Values (TLVs) system, the most widely used occupational heat stress guidelines in the world.

The anthropologist in me was defiant. Ethnographic accounts of work abound in anthropology, and anthropological accounts often make granular observations on what workers do during both work and break hours. Indeed, anthropologists of work are often anthropologists of non-work. And non-work time is complex, especially in informal forms of work where heat risk may be highest. For many informal workers, rest is not a discrete block carved out of work. It is something interleaved, or as Kathleen Millar (2015) writes, 'woven' into work, entangled with eating, talking, waiting, tending to others, folded into the rhythm of tasks rather than imposed from a schedule. This woven temporality of work-rest in informal work is not only prevalent but is often considered valuable by workers.

'Two construction workers in hard hats rest on a site. Passive rest is unlikely to achieve cooling' - Photo by Radik2707 on Pexels

In such situations, were a regimented schedule of cooling rest breaks to be introduced to protect workers, would it work? Guided by TLV-like models that depend on abstractions of the working body, such a policy would make no room for workers' own situated understanding of work and non-work. It is bound to be hindered by low uptake among workers. Indeed, this is already observable from the corpus of literature on work and heat stress: that workers often remain in hot environments during break hours, prioritizing the social functions of the break over cooling (Ioannou et al. 2017; Crowe et al. 2013); that experienced workers manage their bodily heat through complex and skilful working practices (Oppermann et al. 2018; 2020); that precariously positioned piece-rate workers continue working in the heat at risk to their health, even defying protective heat advice from their supervisors (Wadsworth et al. 2019). Workers' subjective understanding of desirable work-rest rhythms is vital, as is an understanding of relations of power when it comes to rest. Rest is not a neutral intervention. The inequality of access to rest, and how rest is withheld and penalised, is often bound up with the very relations of power that produce heat exposure in the first place.

These were the starting ideas of the paper I co-wrote with Laurie Parsons, published in Geo: Geography and Environment (Mishra and Parsons 2026). Beyond the reasons why we chose to write this paper, engaging with the question of how rest is positioned within science and policy was deeply rewarding, exceeding the immediate problematic and indeed our expectations.

Physiologically, it turns out that the cooling of the body from rest is much less straightforward than its policy role implies. A working body in the heat accumulates heat faster than it can shed it, and core temperature climbs toward levels that, if sustained, become dangerous (Kenny and Jay 2013). Rest is supposed to reverse this, but the relationship between rest and core temperature is non-linear. Sweating is impeded during rest and our muscles store and transfer heat to the core, sustaining dangerous levels of core body temperature for up to 90 minutes after the onset of rest (Kenny et al. 2006; Kenny and Jay 2013). A systematic review by Matt Brearley and colleagues (2023) found that passive rest, without active cooling, frequently fails to return the core temperature of heat-exposed workers to safe levels in any timely way.

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Following the reasons why scientific heat stress models and understandings, and the guidelines developed on them, feel so removed from the considerations of heat exposure in actual working conditions was, historically, again highly rewarding. In tracing the history of science and policy, we developed the concept of the 'recovery–productivity calculus' as the dominant scientific and policy frame on rest. The calculus reads rest as a tool of bodily recovery, measured in the cooling of the body, and as functional to keeping the worker productive. The sole consideration is therefore the recovery and productivity implications of rest, to the exclusion of the various social functions and meanings of rest.

The dominance of this narrow calculus was not pre-destined; it owed to the historical legacy of scientific research on heat and rest. A large portion of knowledge about how bodies respond to heat originated not in workplaces but in militaries, in research conducted on soldiers. A further dominant strand of research is laboratory experiments conducted with volunteers. Much of the thermal physiological knowledge applied to the workplace is generalised from contexts outside of ordinary work.

A predecessor to the study of heat-health is the legacy of the early-twentieth-century science of industrial fatigue, whose history Anson Rabinbach (1990) traces in detail. Fatigue research established the laboratory as an adequate stand-in for the worksite, and it installed productivity as the measure of a body's healthy capacity (Scheffler 2011; Blayney 2019). The question of whether a worker was coping came to be answered by how much work the worker could still do. Further to this historical legacy was an important technological constraint. Tracking heat or body temperature within a working body was unreliable, invasive, and expensive. This kept research tethered to settings where measurement was easier. The combined effect was a discipline whose authority on occupational heat was built largely without considering actual working conditions.

This is changing. Access to better, cheaper technology for tracking core body temperatures has allowed an increasing number of scientific studies to be performed in worksites, which automatically become conversant with actual conditions of work (Parsons et al. 2025). Studies that follow workers through their shifts have produced a far more granular picture of exposure and revealed how uneven its distribution is, bolstering heat further as a question of social and environmental justice (Parsons et al. 2025). Further, ethnographers and cultural geographers are now a visible presence in the field of occupational heat health, and their arrival has added layers of social context and critical analysis. The early critical work on heat established that exposure is unequal, that thermal inequality maps closely onto older inequalities of class, race, caste, migration status and informality. That insight remains foundational. But the critical conversation is increasingly moving toward a more situated set of questions: what heat and exhaustion mean to those who endure them, how heat is co-produced through the labour process itself, and how workers' own ways of coping with heat are shaped by cultural understanding and by the narrow room for manoeuvre that their labour regimes allow.

Drawing on the lessons of recent critical work, we assert in our paper that rest is obviously a powerful remedy for heat stress. But rest that is prescribed in a top-down manner, without regard for how workers experience their own heat exposure or for what resting will cost a worker, will not do the work it is meant to. A more encompassing view of rest brings into focus a practice that the policy conversation has largely overlooked. This is self-pacing, the continual adjustment of effort to the body's own reading of its condition, a form of rest performed within work rather than apart from it. The scientific literature that has studied workplaces where workers are encouraged to self-pace attests to its high level of effectiveness in protecting workers, even in hot working environments (Brake and Bates 2002; Brearley et al. 2015; Kenny et al. 2012). Self-pacing is by nature subjective and dependent on each worker's assessment of their own body. It privileges the judgement of the worker, feeding into questions of workers' autonomy and power.

The politicization of heat inherent within self-pacing is indeed its value, because heat stress is a political problem. The conclusion that critical scholarship on heat keeps arriving at, and that our study of rest makes clear, is that heat in the working body cannot be managed simply by techno-managerial solutions. Politicizing heat stress is the answer. Preventing chronic heat stress will inevitably mean confronting the arrangements of power that decide who gets to rest.

References

Barak, O. (2024). Heat, a history: Lessons from the Middle East for a warming planet. University of California Press.

Blayney, S. (2019). Industrial fatigue and the productive body: The science of work in Britain, c. 1900–1918. Social History of Medicine, 32(2), 310–328. https://doi.org/10.1093/shm/hkx077

Brake, D. J., & Bates, G. P. (2002). Deep body core temperatures in industrial workers under thermal stress. Journal of Occupational and Environmental Medicine, 44(2), 125–135. https://doi.org/10.1097/00043764-200202000-00007

Brearley, M., Berry, R., Hunt, A. P., & Pope, R. (2023). A systematic review of post-work core temperature cooling rates conferred by passive rest. Biology, 12(5), 695. https://doi.org/10.3390/biology12050695

Brearley, M., Harrington, P., Lee, D., & Taylor, R. (2015). Working in hot conditions—A study of electrical utility workers in the Northern Territory of Australia. Journal of Occupational and Environmental Hygiene, 12(3), 156–162. https://doi.org/10.1080/15459624.2014.957831

Chamayou, G. (2025). The birth of thermopolitics: Wet-bulb temperatures, industrial microclimates, and class struggle in the early 20th century. Social Studies of Science. https://doi.org/10.1177/03063127251326878

Crowe, J., Wesseling, C., Solano, B. R., Umaña, M. P., Ramírez, A. R., Kjellstrom, T., Morales, D., & Nilsson, M. (2013). Heat exposure in sugarcane harvesters in Costa Rica. American Journal of Industrial Medicine, 56(10), 1157–1164. https://doi.org/10.1002/ajim.22204

Ioannou, L. G., Tsoutsoubi, L., Samoutis, G., Bogataj, L. K., Kenny, G. P., Nybo, L., Kjellstrom, T., & Flouris, A. D. (2017). Time-motion analysis as a novel approach for evaluating the impact of environmental heat exposure on labor loss in agriculture workers. Temperature, 4(3), 330–340. https://doi.org/10.1080/23328940.2017.1338210

Keegan, C. (2023). Reconsidering the "nature" of agriculture: Racial capitalism, H-2A labor, and political ecologies of extreme heat in Georgia. Annals of the American Association of Geographers, 113(10), 2287–2302. https://doi.org/10.1080/24694452.2023.2223607

Kenny, G. P., & Jay, O. (2013). Thermometry, calorimetry, and mean body temperature during heat stress. In R. Terjung (Ed.), Comprehensive Physiology (1st ed., pp. 1689–1719). Wiley. https://doi.org/10.1002/cphy.c130011

Kenny, G. P., Jay, O., & Zaleski, W. M., et al. (2006). Postexercise hypotension causes a prolonged perturbation in esophageal and active muscle temperature recovery. American Journal of Physiology, 291(3), R580–R588. https://doi.org/10.1152/ajpregu.00918.2005

Kenny, G. P., Vierula, M., Maté, J., Beaulieu, F., Hardcastle, S. G., & Reardon, F. (2012). A field evaluation of the physiological demands of miners in Canada's deep mechanized mines. Journal of Occupational and Environmental Hygiene, 9(8), 491–501. https://doi.org/10.1080/15459624.2012.693880

Macktoom, S., Anwar, N. H., & Cross, J. (2024). Hot climates in urban South Asia: Negotiating the right to and the politics of shade at the everyday scale in Karachi. Urban Studies, 61(15), 2945–2962. https://doi.org/10.1177/00420980231195204

Millar, K. M. (2015). The tempo of wageless work. Focaal, 73, 28–40. https://doi.org/10.3167/fcl.2015.730103

Mishra, P., & Parsons, L. (2026). Rest in a warming workplace: Resituating the science and policy of non-work under climate change. Geo: Geography and Environment, 13(1), e70070. https://doi.org/10.1002/geo2.70070

Nading, A. M. (2025). The kidney and the cane: Planetary health and plantation labor in Nicaragua. Duke University Press. https://doi.org/10.1215/9781478060864

Nag, P. K., Dutta, P., & Nag, A. (2013). Critical body temperature profile as indicator of heat stress vulnerability. Industrial Health, 51(1), 113–122. https://doi.org/10.2486/indhealth.2012-0108

Oppermann, E., Brearley, M., Law, L., Smith, J. A., Clough, A., & Zander, K. (2017). Heat, health, and humidity in Australia's monsoon tropics: A critical review of the problematization of 'heat' in a changing climate. WIREs Climate Change, 8(4), e468. https://doi.org/10.1002/wcc.468

Oppermann, E., Strengers, Y., Maller, C., Rickards, L., & Brearley, M. (2018). Beyond threshold approaches to extreme heat: Repositioning adaptation as everyday practice. Weather, Climate, and Society, 10(4), 885–898. https://doi.org/10.1175/WCAS-D-17-0084.1

Oppermann, E., Walker, G., & Brearley, M. (2020). Assembling a thermal rhythmanalysis: Energetic flows, heat stress and polyrhythmic interactions in the context of climate change. Geoforum, 108, 275–285. https://doi.org/10.1016/j.geoforum.2019.09.012

Parsons, L., Mishra, P., Cole, J., Lawreniuk, S., Biswas, C. & Serey, S. (forthcoming). Hotter trends: Working conditions and climate-linked heat stress in the Cambodian garment sector. Environment and Planning E.

Parsons, L., Mishra, P., Cole, J., Lawreniuk, S., & Long, L. V. (2025). Climate-linked heat inequality in the global southern workforce: Cambodian workers' economic and health vulnerability to high core temperatures in five occupational sectors. Climate and Development, 17(10), 869–881. https://doi.org/10.1080/17565529.2025.2474026

Rabinbach, A. (1990). The human motor: Energy, fatigue, and the origins of modernity. New York: Basic Books.

Scheffler, R. W. (2011). The fate of a progressive science: The Harvard Fatigue Laboratory, athletes, the science of work and the politics of reform. Endeavour, 35(2–3), 48–54. https://doi.org/10.1016/j.endeavour.2011.05.007

Wadsworth, G., Courville, M., & Schenker, M. (2019). Pay, power, and health: HRI and the agricultural conundrum. Labor Studies Journal, 44(3), 214–235. https://doi.org/10.1177/0160449X18767749