Background To examine the effects of varying doses of caffeine on autonomic reactivation following anaerobic exercise. Methods Recreationally active males ( N = 20; 24 ± 2y) participated in a randomized, double-blind, placebo-controlled, crossover study where participants ingested: [1] Control (CON; no supplement), [2] a non-caffeinated placebo (PLA), [3] 3-mg∙kg − 1 of caffeine (CAF3) or [4] 6-mg∙kg − 1 of caffeine (CAF6) prior to Wingate testing. Parasympathetic (lnRMSSD, primary outcome) and global HRV (lnSDNN, secondary outcome) were assessed at rest (i.e., pre-ingestion), 45-min post-ingestion, and 5-min and 35-min post-exercise recovery. We used a GLM to assess mean (95% CI) changes from pre-ingestion baseline. Results Overall, we observed a significant trend for lnRMSSD and lnSDNN ( both , p = 0.001, ηp 2 = 0.745). Forty-five minutes after treatment ingestion, we observed a significant increase in lnRMSSD for CAF3 (0.15 ms, 95%CI, 0.07,0.24) and CAF6 (0.16 ms, 95%CI, 0.06,0.25), both being significant ( both , p < 0.004) vs. CON (− 0.02 ms, 95%CI, − 0.09,0.04). Five-minutes after exercise, all treatments demonstrated significant declines in lnRMSSD vs. baseline ( all , p < 0.001). After 35-min of recovery, lnRMSSD returned to a level not significantly different than baseline for CAF3 (0.03 ms, 95%CI, − 0.05, 0.12) and CAF6 (− 0.03 ms, 95%CI, − 0.17, 0.10), while PLA (− 0.16 ms, 95%CI, − 0.25, − 0.06) and CON (− 0.17 ms, 95%CI, − 0.28, − 0.07) treatments remained significantly depressed. A similar pattern was also observed for SDNN. Conclusion Caffeine ingestion increases resting cardiac autonomic modulation and accelerates post-exercise autonomic recovery after a bout of anaerobic exercise in recreationally active young men. However, no differences between caffeine doses on cardiac autonomic reactivity were observed.

中文翻译：

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不同剂量的咖啡因对休闲运动员急性无氧运动后心脏副交感神经再激活的影响

背景 研究不同剂量的咖啡因对无氧运动后自主神经重新激活的影响。方法 活跃于娱乐活动的男性（N = 20；24 ± 2 岁）参加了一项随机、双盲、安慰剂对照、交叉研究，其中参与者摄入：[1] 对照（CON；无补充剂），[2] 不含咖啡因的饮料在 Wingate 测试之前，安慰剂 (PLA)、[3] 3-mg∙kg − 1 咖啡因 (CAF3) 或 [4] 6-mg∙kg − 1 咖啡因 (CAF6)。副交感神经（lnRMSSD，主要结果）和整体 HRV（lnSDNN，次要结果）在休息时（即摄入前）、摄入后 45 分钟以及运动后恢复 5 分钟和 35 分钟进行评估。我们使用 GLM 来评估相对于摄入前基线的平均变化（95% CI）。结果 总体而言，我们观察到 lnRMSSD 和 lnSDNN 的显着趋势（两者，p = 0.001，ηp 2 = 0.745）。摄入治疗后 45 分钟，我们观察到 CAF3（0.15 ms，95%CI，0.07,0.24）和 CAF6（0.16 ms，95%CI，0.06,0.25）的 lnRMSSD 显着增加，两者均显着（均， p < 0.004) 与 CON (− 0.02 ms, 95% CI, − 0.09,0.04)。运动后五分钟，所有治疗均显示 lnRMSSD 与基线相比显着下降（全部，p < 0.001）。恢复 35 分钟后，lnRMSSD 恢复到与 CAF3（0.03 ms，95%CI，− 0.05，0.12）和 CAF6（− 0.03 ms，95%CI，− 0.17，0.10）基线无显着差异的水平，而PLA（− 0.16 ms，95% CI，− 0.25，− 0.06）和 CON（− 0.17 ms，95% CI，− 0.28，− 0.07）治疗仍然显着抑制。SDNN 也观察到类似的模式。结论 对于休闲活跃的年轻男性来说，摄入咖啡因可增加静息心脏自主神经调节，并加速进行一次无氧运动后运动后自主神经恢复。然而，没有观察到咖啡因剂量对心脏自主反应的影响存在差异。