It is generally accepted that older adults display an impaired cardiovascular response to heat stress, and it has been suggested that this impaired response contributes to their increased risk of mortality during extreme heat events. Seminal studies have shown that cutaneous vasodilation, the redistribution of blood flow from visceral organs and the increase in cardiac output are blunted in older adults during passive heating. The blunted rise of cardiac output was initially attributed to an inability to maintain stroke volume, suggesting that cardiac systolic and/or diastolic function does not adequately respond to the constraints of heat stress in older adults. Recent studies evaluated potential mechanisms underlying these seminal findings and their results challenge some of these initial observations. Notably, stroke volume is maintained during heat exposure in older adults and studies have provided evidence for preserved cardiac systolic and diastolic functions in this population. Nonetheless, a blunted increase in cardiac output during heat exposure remains a consistent observation in older adults although it is now attributed to a blunted increase in heart rate. Recent studies have also evaluated the possibility that the attenuated capacity of aged skin to vasodilate contributes to a blunted increase in cardiac output during heat stress. The objective of this Mini-Review is to highlight these recent advances and challenge the longstanding view that the control of stroke volume during heat exposure is compromised in older adults. By doing so, our intent is to stimulate future studies to evaluate several unanswered questions in this area of research.

中文翻译：

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老年人热应激期间的心血管控制：更新的时间

公认的是，老年人对热应激的心血管反应减弱，并且已表明这种减弱的反应导致其在极端高温事件中死亡的风险增加。开创性研究表明，在被动加热过程中，老年人的皮肤血管舒张，内脏器官血流的重新分配和心输出量的增加受到影响。起初心输出量下降的原因归因于无法维持中风量，这表明心脏收缩和/或舒张功能不能充分响应老年人的热应激。最近的研究评估了这些开创性发现的潜在机制，其结果挑战了一些初步观察结果。值得注意的是 在老年人中，中风的量在维持热量的过程中得以维持，并且研究提供了该人群心脏收缩和舒张功能得以维持的证据。尽管如此，在老年人中，热暴露期间心输出量的缓慢增加仍然是一贯的观察结果，尽管现在这归因于心率的缓慢增加。最近的研究还评估了衰老的皮肤血管舒张能力减弱导致热应激期间心输出量增加的可能性。这份小型复习的目的是强调这些最新进展，并挑战长期以来的观点，即老年人在热暴露期间对中风量的控制受到损害。通过这样做，我们的目的是激发未来的研究，以评估该研究领域中的一些未解决的问题。