Dark chocolate (DC) is high in flavonoids and has been shown to increase nitric oxide in the blood. Increased nitric oxide has the potential to improve delivery of oxygen to muscle, especially in hypoxic conditions, such as altitude. Our aim was to assess the impact of DC supplementation on cycling performance at altitude. Twelve healthy, trained cyclists (n = 2 females, n = 10 males; age = 35 [12] years; height = 177 [7] cm; mass = 75.2 [11.0] kg; VO₂max = 55 [6] ml·kg⁻¹·min⁻¹) were randomized to supplement with 60 g of DC or placebo twice per day for 14 days in a double-blind crossover study. After the 2 weeks of supplementation, the participants attended a laboratory session in which they consumed 120 g of DC or placebo and then cycled for 90 min at 50% peak power output, followed immediately by a 10-km time trial (TT) at simulated altitude (15% O₂). The plasma concentration of blood glucose and lactate were measured before and at 15, 30, 60, and 90 min during the steady-state exercise and post TT, while muscular and prefrontal cortex oxygenation was measured continuously throughout exercise using near-infrared spectroscopy. DC resulted in a higher concentration of blood glucose (5.5 [0.5] vs. 5.3 [0.9] mmol/L) throughout the trial and lower blood lactate concentration following the TT (7.7 [1.92] vs. 10.0 [4.6] mmol/L) compared with the placebo. DC had no effect on the TT performance (19.04 [2.16] vs. 19.21 ± 1.96 min) or oxygenation status in either the prefrontal cortex or muscle. The authors conclude that, although it provided some metabolic benefit, DC is not effective as an ergogenic aid during TT cycling at simulated altitude.

黑巧克力 (DC) 富含黄酮类化合物，已被证明可以增加血液中的一氧化氮。增加一氧化氮有可能改善肌肉的氧气输送，尤其是在缺氧条件下，例如海拔高度。我们的目的是评估补充直流电对高原骑行表现的影响。十二名健康、训练有素的自行车手（n  = 2 名女性，n  = 10 名男性；年龄 = 35 [12] 岁；身高 = 177 [7] cm；质量 = 75.2 [11.0] kg；最大摄氧量 2 = ₅₅ [6] ml·在双盲交叉研究中，体重（kg ^-1 ·min ^{-1 ）被随机每天补充两次 60 g DC 或安慰剂，持续 14 天。}补充两周后，参与者参加了实验室会议，其中他们消耗了 120 克 DC 或安慰剂，然后以 50% 峰值功率输出骑车 90 分钟，随后立即在模拟环境下进行 10 公里计时赛 (TT)。海拔高度（15% O ₂）。在稳态运动期间和 TT 后测量血糖和乳酸的血浆浓度，并在稳态运动期间和 15、30、60 和 90 分钟测量血浆浓度，同时使用近红外光谱在整个运动过程中连续测量肌肉和前额皮质氧合。DC 导致整个试验期间血糖浓度较高（5.5 [0.5] vs. 5.3 [0.9] mmol/L），并且 TT 后血乳酸浓度较低（7.7 [1.92] vs. 10.0 [4.6] mmol/L）与安慰剂相比。DC 对 TT 表现（19.04 [2.16] vs. 19.21 ± 1.96 分钟）或前额皮质或肌肉的氧合状态没有影响。作者得出的结论是，尽管 DC 提供了一些代谢益处，但在模拟海拔的 TT 骑行过程中，DC 作为增效剂的作用并不有效。