The Healthspan Map · Sleep (Ch6)

Caffeine — mind amount & timing

What this is linked to

Where Caffeine — mind amount & timing is linked — 8 sources.In the order the Map holds them: strongest evidence first. That is a statement about the evidence, not about what matters most.
Nutrient or lever	Direction	Strength	Evidence type	What was found	Source
Caffeine — mind amount & timing	Do this	Strong	RCT / meta-analysis	Higher caffeine intake raises anxiety risk dose-dependently (SMD 0.94; steep >~400 mg/day).	Caffeine-anxiety meta-analysis (Front. Psychol. 2024) (opens in a new tab)
Caffeine — mind amount & timing	Do this	Moderate	Systematic review	Caffeine supports alertness, but poor timing/overuse disrupts sleep and withdrawal causes brain fog.	Sleep-cognition overview 2023 (opens in a new tab)
Caffeine — mind amount & timing	Do this	Moderate	Established clinical	Late-day caffeine erodes sleep quality and masks sleep debt, producing net next-day fatigue — timing matters more than amount.	Excessive daytime sleepiness review (AFP) (opens in a new tab)
Caffeine — mind amount & timing	Do this	Emerging	RCT / meta-analysis	Caffeine can relax the LES and trigger reflux/heartburn in sensitive people.	Caffeine reflux trigger (opens in a new tab)
Caffeine — mind amount & timing	Do this	Moderate	Systematic review	Irregular or high caffeine intake and caffeine withdrawal trigger headaches; low, stable intake is advised.	Robblee & Starling 2019 (opens in a new tab)
Caffeine — mind amount & timing	Do this	Moderate	RCT / meta-analysis	Large caffeine doses (200-300 mg, energy drinks) acutely raise blood pressure ~8/6 mmHg for hours, especially in non-habitual users; habitual coffee is neutral.	Caffeine/coffee & BP meta (opens in a new tab)
Caffeine — mind amount & timing	Do this	Strong	RCT / meta-analysis	Caffeine blocks adenosine receptors, cutting sleep pressure and deep (N3) sleep; effects persist for hours (half-life 4-6 h).	Caffeine-sleep meta 2023 (opens in a new tab)
Caffeine — mind amount & timing	Do this	Moderate	RCT / meta-analysis	Higher caffeine intake raises anxiety risk dose-dependently; habitual use heightens cortisol reactivity to stress.	Caffeine–anxiety meta-analysis (Front. Psychol. 2024) (opens in a new tab)