Sudden deaths without known causes have been reported among rural workers in the last decade, especially in low and middle-income countries. The current study aimed to analyse the association between awakening cortisol response and cardiovascular performance in rural workers before and after the harvesting period. Fifty-four rural male workers and 48 residents were included (non-rural workers) from a sugarcane production area in São Paulo, Brazil. Morning salivary cortisol were analysed before and 7 months after the beginning of burnt sugarcane harvesting. Cardiovascular performance (blood pressure, pulse pressure and heart rate HR) was evaluated using the Incremental Shuttle Walking Test (ISWT). Our findings revealed a negative association between CAR and cardiovascular performance in rural workers at the harvesting period. Specifically, morning cortisol levels significantly increased after seven months of intense harvesting activity, allied to improvements in physical performance, systolic blood pressure and heart rate reactivity to a cardiopulmonary task. No association was observed in the resident group. Altogether, these findings suggest that, at least in the short-term, rural workers presented an adaptive response to the physical demands of sugarcane harvesting work. Longitudinal studies are essential to investigate the long-term effects of harvesting activity on rural workers' health.

中文翻译：

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甘蔗农民工觉醒皮质醇水平与心血管功能的关系

在过去十年中，农村工人中出现了不明原因的突然死亡，特别是在低收入和中等收入国家。本研究旨在分析收获期前后农村工人的皮质醇觉醒反应与心血管表现之间的关系。包括来自巴西圣保罗甘蔗产区的 54 名农村男性工人和 48 名居民（非农村工人）。在烧焦的甘蔗收获开始之前和之后 7 个月分析早晨唾液皮质醇。使用增量穿梭行走测试 (ISWT) 评估心血管性能（血压、脉压和心率 HR）。我们的研究结果揭示了收获期农村工人的 CAR 与心血管表现之间存在负相关。具体来说，经过七个月的高强度采摘活动后，早晨的皮质醇水平显着增加，这与身体机能、收缩压和心率对心肺任务的反应有关。在居民组中没有观察到关联。总之，这些研究结果表明，至少在短期内，农村工人对甘蔗收割工作的体力需求做出了适应性反应。纵向研究对于调查收割活动对农村工人健康的长期影响至关重要。这些发现表明，至少在短期内，农村工人对甘蔗收割工作的体力需求做出了适应性反应。纵向研究对于调查收割活动对农村工人健康的长期影响至关重要。这些发现表明，至少在短期内，农村工人对甘蔗收割工作的体力需求做出了适应性反应。纵向研究对于调查收割活动对农村工人健康的长期影响至关重要。