Heart Institute (InCor), University of São Paulo Medical School, São Paulo, BRAZIL.
Med Sci Sports Exerc. 2018 Mar;50(3):596-602. doi: 10.1249/MSS.0000000000001456.
Increased resting muscle sympathetic nerve activity (MSNA) and lower forearm blood flow (FBF) were observed in young men who use anabolic androgenic steroids (AAS). However, the response of MSNA and FBF in AAS users triggered by muscle mechanoreflex and central command has never been tested. In addition, we evaluated the blood pressure (BP) and heart rate (HR) responses during these maneuvers.
Nineteen AAS users (AASU) 31 ± 6 yr of age and 18 AAS nonusers (AASNU) 29 ± 4 yr of age were recruited. All participants were involved in strength training. AAS use was determined using a urine test (liquid chromatography with tandem mass spectrometry). MSNA was measured using the microneurography technique. FBF was measured by using venous occlusion plethysmography. BP was measured using an automatic oscillometric device. HR was recorded continuously through ECG. Isometric handgrip exercise was performed at 30% of the maximal voluntary contraction for 3 min, and mental stress was elicited by the Stroop color-word test for 4 min.
The MSNA and FBF responses during exercise were similar between AASU and AASNU, with a trend toward higher MSNA (bursts per minute; P = 0.084) and lower forearm vascular conductance (FVC; units; P = 0.084) in AASU than in AASNU. During mental stress, AASU showed a significantly higher MSNA (P < 0.05) and lower FBF (P < 0.05) compared with AASNU. During both maneuvers, HR and BP increased linearly in both groups; however, AASU showed a significantly higher HR compared with AASNU.
During muscle mechanoreflex activation (isometric exercise), AASU have normal MSNA and FBF responses, whereas during central command (mental stress) stimulation, AASU have exacerbated MSNA and blunted vasodilation. Therefore, mental stress seems to exacerbate neurovascular control throughout stress reaction situations in AASU.
在使用合成代谢雄激素类固醇（AAS）的年轻男性中，观察到静息时肌肉交感神经活动（MSNA）增加和前臂血流（FBF）降低。然而，AAS 使用者的 MSNA 和 FBF 对肌肉机械反射和中枢指令的反应从未被测试过。此外，我们评估了这些操作过程中的血压（BP）和心率（HR）反应。
招募了 19 名 AAS 使用者（AASU），年龄为 31±6 岁，18 名 AAS 非使用者（AASNU），年龄为 29±4 岁。所有参与者都参与了力量训练。AAS 使用情况通过尿液测试（液相色谱-串联质谱法）确定。MSNA 通过微神经记录技术测量。FBF 通过静脉闭塞体积描记法测量。BP 通过自动示波装置测量。HR 通过心电图连续记录。等长握力运动以 30%的最大自主收缩力进行 3 分钟，精神压力通过 Stroop 颜色-单词测试诱发 4 分钟。
运动过程中 AASU 和 AASNU 的 MSNA 和 FBF 反应相似，AASU 的 MSNA（每分钟爆发次数；P=0.084）和 FVC（单位；P=0.084）略高于 AASNU。在精神压力下，AASU 的 MSNA 明显高于 AASNU（P<0.05），FBF 明显低于 AASNU（P<0.05）。在两种操作中，两组的 HR 和 BP 均呈线性增加；然而，AASU 的 HR 明显高于 AASNU。
在肌肉机械反射激活（等长运动）时，AASU 的 MSNA 和 FBF 反应正常，而在中枢指令（精神压力）刺激时，AASU 的 MSNA 加剧，血管扩张减弱。因此，在 AASU 中，精神压力似乎会加剧神经血管控制，从而加剧应激反应情况下的情况。
