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title: Caffeine
created: 2024-11-18T09:18:12
modified: 2025-11-06T06:38:48
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提神 ≠ 專注

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Caffeine is a diuretic, causing the loss of fluid, sodium and other electrolytes.

* Consume **equal** volumes of water with your caffeine to avoid jitteriness,[^1] blurry vision or a low blood sugar feeling.
	* Side Effect: 心悸（心跳加速）& 焦慮
* Ideally, add a small pinch of sea salt, table salt or electrolyte-replacement powder.

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Do not drink coffee immediately upon waking. Instead, delaying coffee consumption for a minimum of **1.5–2 hours** after waking.

* Caffeine wakes you up by fooling/blocking the [adenosine](adenosine.md) from adhering to its normal receptors in the brain. You want your body to clear out the adenosine before adding caffeine, otherwise you’ll feel drowsy again once the caffeine wears off.
* This could greatly help to get rid of the “[afternoon crash/post-lunch slump.](napping.md)”
* The best time to drink coffee is likely **mid-to-late morning**, when your [cortisol](cortisol.md) levels start to drop.

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Consuming caffeine on an **empty stomach** allows for a smaller dose to have the same stimulant and performance-enhancing effects.

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Avoid drinking caffeine for least **10–12 hours** before bedtime.

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Peak focus and alertness will occur **~30 minutes** after caffeine consumption and last **~60 minutes**.

* To experience the maximum performance-enhancing effects of caffeine, **abstain from** caffeine for a few days (**3–20 days**). Then, on the day of the physical challenge (e.g., marathon), ingest caffeine **~30 minutes** before the start.

[^1]: 緊張不安；心煩意亂