Sleeping with low carbohydrate (CHO) availability is a dietary strategy that may enhance training adaptation. However, the impact on an athlete's health is unclear. This study quantified the effect of a short-term "sleep-low" dietary intervention on markers of iron regulation and immune function in athletes. In a randomized, repeated-measures design, 11 elite triathletes completed two 4-day mixed cycle run training blocks. Key training sessions were structured such that a high-intensity training session was performed in the field on the afternoon of Days 1 and 3, and a low-intensity training (LIT) session was performed on the following morning in the laboratory (Days 2 and 4). The ingestion of CHO was either divided evenly across the day (HIGH) or restricted between the high-intensity training and LIT sessions, so that the LIT session was performed with low CHO availability (LOW). Venous blood and saliva samples were collected prior to and following each LIT session and analyzed for interleukin-6, hepcidin 25, and salivary immunoglobulin-A. Concentrations of interleukin-6 increased acutely after exercise (p < .001), but did not differ between dietary conditions or days. Hepcidin 25 increased 3-hr postexercise (p < .001), with the greatest increase evident after the LOW trial on Day 2 (2.5 ± 0.9 fold increase ±90% confidence limit). The salivary immunoglobulin-A secretion rate did not change in response to exercise; however, it was highest during the LOW condition on Day 4 (p = .046). There appears to be minimal impact to markers of immune function and iron regulation when acute exposure to low CHO availability is undertaken with expert nutrition and coaching input.

中文翻译：

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周期性膳食碳水化合物对精英铁人三项运动员铁调节和免疫功能的影响。

低碳水化合物 (CHO) 可用性睡眠是一种可以增强训练适应性的饮食策略。然而，对运动员健康的影响尚不清楚。这项研究量化了短期“低睡眠”饮食干预对运动员铁调节和免疫功能标志物的影响。在随机、重复测量设计中，11 名精英铁人三项运动员完成了两个为期 4 天的混合循环跑步训练块。重点培训课程的结构是在第 1 天和第 3 天下午在现场进行高强度培训课程，并在第二天早上在实验室进行低强度培训 (LIT) 课程（第 2 天和第 3 天） 4）。CHO 的摄入要么在一天中平均分配 (HIGH)，要么限制在高强度训练和 LIT 课程之间，以便在低 CHO 可用性 (LOW) 下执行 LIT 会话。在每次 LIT 之前和之后收集静脉血和唾液样本，并分析白细胞介素 6、铁调素 25 和唾液免疫球蛋白 A。运动后白细胞介素 6 的浓度急剧增加（p < .001），但在饮食条件或天数之间没有差异。运动后 3 小时，铁调素 25 增加（p < .001），在第 2 天的 LOW 试验后明显增加（增加 2.5 ± 0.9 倍 ± 90% 置信限）。唾液免疫球蛋白-A 的分泌率不会随着运动而改变；然而，它在第 4 天的 LOW 条件下最高（p = .046）。