Background With climate change, adverse human health effects caused by heat exposure are of increasing public health concern. Forests provide beneficial ecosystem services for human health, including local cooling. Few studies have assessed the relationship between deforestation and heat-related health effects in tropical, rural populations. We sought to determine whether deforested compared to forested landscapes are associated with increased physiological heat strain in a rural, tropical environment. Methods We analyzed data from 363 healthy adult participants from ten villages who participated in a two-by-two factorial, randomized study in East Kalimantan, Indonesia from 10/1/17 to 11/6/17. Using simple randomization, field staff allocated participants equally to different conditions to conduct a 90-minute outdoor activity, representative of typical work. Core body temperature was estimated at each minute during the activity using a validated algorithm from baseline oral temperatures and sequential heart rate data, measured using chest band monitors. We used linear regression models, clustered by village and with a sandwich variance estimator, to assess the association between deforested versus forested conditions and the number of minutes each participant spent above an estimated core body temperature threshold of 38.5°C. Results Compared to those in the forested condition (n=172), participants in the deforested condition (n=159) spent an average of 3.08 (95% CI 0.57, 5.60) additional minutes with an estimated core body temperature exceeding 38.5°C, after adjustment for age, sex, body mass index, and experiment start time, with a larger difference among those who began the experiment after 12 noon (5.17 [95% CI 2.20, 8.15]). Conclusions In this experimental study in a tropical, rural setting, activity in a deforested versus a forested setting was associated with increased objectively measured heat strain. Longer durations of hyperthermia can increase the risk of serious health outcomes. Land use decisions should consider the implications of deforestation on local heat exposure and health as well as on forest services, including carbon storage functions that impact climate change mitigation.

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与森林砍伐地区相比，在森林砍伐地区工作与人类热应变之间的关联：在热带乡村环境中进行的一项实验研究

背景 随着气候变化，热暴露对人类健康造成的不利影响日益引起公众健康关注。森林为人类健康提供有益的生态系统服务，包括局部降温。很少有研究评估森林砍伐与热带农村人口与高温相关的健康影响之间的关系。我们试图确定与森林景观相比，森林砍伐是否与农村热带环境中生理热应激的增加有关。方法 我们分析了来自 10 个村庄的 363 名健康成人参与者的数据，这些参与者于 2017 年 10 月 1 日至 2017 年 6 月 11 日在印度尼西亚东加里曼丹参加了一项二乘二析因、随机研究。现场工作人员采用简单的随机化方法，将参与者平均分配到不同的条件下，进行 90 分钟的户外活动，代表典型的工作。使用经过验证的算法根据基线口腔温度和连续心率数据（使用胸带监测器测量）来估计活动期间每分钟的核心体温。我们使用线性回归模型，按村庄聚类并使用三明治方差估计器，来评估森林砍伐与森林条件以及每个参与者在估计核心体温阈值 38.5°C 之上度过的分钟数之间的关联。结果 与森林条件下的参与者 (n=172) 相比，森林砍伐条件下的参与者 (n=159) 平均多花 3.08 分钟 (95% CI 0.57, 5.60)，估计核心体温超过 38.5°C，调整年龄、性别、体重指数和实验开始时间后，中午12点后开始实验的人差异较大（5.17 [95% CI 2.20, 8.15]）。结论 在这项热带乡村环境的实验研究中，与森林砍伐环境相比，森林砍伐环境中的活动与客观测量的热应变增加有关。较长时间的高热会增加严重健康后果的风险。土地利用决策应考虑森林砍伐对当地热暴露和健康以及森林服务的影响，包括影响减缓气候变化的碳储存功能。