Caffeine intake
mg/day
Milligrams of caffeine per day from coffee, tea, or capsules. People take it to stay awake; the atlas tracks the dose.
Caffeine blocks adenosine receptors. A 150 mg capsule and a strong coffee are the same exposure if the milligrams match. Instant coffee, espresso, and energy drinks are ways to take that dose, not separate variables.
Also called caffeine, coffee.
Connected relationships
Meta-analysis · Low
Caffeine intake→All-cause mortality
Higher Caffeine intake moves All-cause mortality in a non-linear way. Dose or timing can flip the sign.
Li 2020 pooled 21 cohort articles (10,103,115 people, 240,303 deaths) and found a nonlinear inverse between coffee and all-cause death: three cups a day against none or rare sat at relative risk 0.87 (0.84 to 0.89). Tsujimoto 2017 saw the same U in caffeine milligrams. Nobody assigned a dose.
Randomized trial · Moderate
Caffeine intake→Sleep duration and regularity
Higher Caffeine intake moves Sleep duration and regularity only in some conditions. Read the mechanism.
In twenty young men, Weibel 2021 found that 450 mg of daytime caffeine a day left nighttime sleep length and stages unchanged, but delayed REM and made waking harder when sleep was pushed into the morning.
Sources
- Q Li et al. (2020). Caffeinated and decaffeinated coffee consumption and risk of all-cause mortality: a dose-response meta-analysis of cohort studies.
- E Lopez-Garcia et al. (2008). The relationship of coffee consumption with mortality.
- B Zhou et al. (2025). Coffee Consumption and Mortality among United States Adults: A Prospective Cohort Study.
- T Tsujimoto et al. (2017). Association Between Caffeine Intake and All-Cause and Cause-Specific Mortality: A Population-Based Prospective Cohort Study.
- J Weibel et al. (2021). The impact of daily caffeine intake on nighttime sleep in young adult men.
- J Weibel et al. (2021). Regular Caffeine Intake Delays REM Sleep Promotion and Attenuates Sleep Quality in Healthy Men.