介绍:
1. Over 100,000 metric tons of caffeine are consumed around the world every year. That's equivalent to the weight of 14 Eiffel Towers. Most of this caffeine is consumed in coffee and tea, but it's also ingested in some sodas, chocolate, caffeine pills, and even beverages labeled decaf.
2. Caffeine helps us feel alert, focused, happy, and energetic, even if we haven't had enough sleep. But it can also raise our blood pressure, and make us feel anxious. It's the world’s most widely used drug.
3. In the human body, caffeine acts as a stimulant for the central nervous system. It keeps us awake by blocking one of the body's key sleep-inducing molecules, a substance called adenosine.
4. Caffeine can also boost positive feelings. In some neurons, the adenosine receptors are linked to receptors for another molecule called dopamine. One of dopamine's roles in the brain is to promote feelings of pleasure.
5. Caffeine can also ramp up the body's ability to burn fat. In fact, some sports organizations think that caffeine gives athletes an unfair advantage and have placed limits on its consumption.
全世界每年消耗的咖啡因有10万多吨。这相当于14座埃菲尔铁塔的重量。大部分咖啡因存在于咖啡和茶中，但它也可以通过一些苏打水、巧克力、咖啡因药丸，甚至标有脱咖啡因的饮料摄入。
即使我们没有足够的睡眠，咖啡因也能帮助我们保持警觉、专注、快乐和精力充沛。但它也会升高我们的血压，让我们感到焦虑。它是世界上使用最广泛的药物。
在人体中，咖啡因是中枢神经系统的兴奋剂。它通过阻断人体一种关键的睡眠诱导分子，一种叫做腺苷的物质来让我们保持清醒。
咖啡因也可以促进积极的情绪。在一些神经元中，腺苷的神经末梢与另一种叫做多巴胺的神经末梢相连。多巴胺在大脑中的作用之一是促进愉悦感。
咖啡因还能提高身体燃烧脂肪的能力。事实上，一些体育组织认为咖啡因给了运动员不公平的优势，并对其摄入量进行了限制。
