Lefferts Wesley K, Heffernan Kevin S, Hultquist Eric M, Fehling Patricia C, Smith Denise L
Skidmore College, Saratoga Springs, NY, USA Syracuse University, Syracuse, NY, USA.
Syracuse University, Syracuse, NY, USA.
Vasc Med. 2015 Jun;20(3):222-9. doi: 10.1177/1358863X14566430. Epub 2015 May 4.
This study examined the effects of moderate exercise-induced heat stress (EIHS) on vascular function, central hemodynamic load and indices of coronary perfusion. Vascular-hemodynamic measures were collected in 12 healthy men (aged 22±3 years) pre and post 100 minutes of moderate, intermittent exercise in two randomized conditions: heat stress (HS; wearing firefighter personal protective equipment (PPE)), and no heat stress (NHS; wearing a cooling shirt and equivalent PPE weight). Aortic blood pressure, reflected wave pressure (Pb), systolic (SPTI) and diastolic pressure time-integral (DPTI), and aortic stiffness were assessed before and after each condition. SPTI was significantly greater, and DPTI and Pb were significantly lower for HS-post compared to NHS-post (p<0.05). Pulse wave velocity was not different between conditions. In conclusion, EIHS does not affect aortic stiffness, but increases indices of myocardial work and reduces indices of coronary perfusion which may be related to chronotropic responses to EIHS. The mismatch between oxygen demand and oxygen supply may increase cardiac vulnerability to ischemia during strenuous work in the heat.
本研究考察了中度运动诱导的热应激（EIHS）对血管功能、中心血流动力学负荷和冠状动脉灌注指标的影响。在两种随机条件下，对12名健康男性（年龄22±3岁）在进行100分钟中度间歇性运动前后的血管血液动力学指标进行了收集：热应激（HS；穿着消防员个人防护装备（PPE））和无热应激（NHS；穿着冷却衬衫和同等重量的PPE）。在每种条件前后评估主动脉血压、反射波压力（Pb）、收缩压时间积分（SPTI）和舒张压时间积分（DPTI）以及主动脉僵硬度。与NHS后相比，HS后SPTI显著更高，而DPTI和Pb显著更低（p<0.05）。两种条件下脉搏波速度无差异。总之，EIHS不影响主动脉僵硬度，但会增加心肌做功指标并降低冠状动脉灌注指标，这可能与对EIHS的变时反应有关。在高温环境下剧烈工作期间，氧需求与氧供应之间的不匹配可能会增加心脏对缺血的易感性。
